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1

EA-1131: Relocation of Neutron Tube Target Loading Operation, Los Alamos Laboratory, Los Alamos, New Mexico  

Energy.gov (U.S. Department of Energy (DOE))

This EA evaluates the environmental impacts of the proposal to relocate the Neutron Tube Target Loading operations at the U.S. Department of Energy Los Alamos National Laboratory in New Mexico from...

2

Environmental assessment of the relocation of Neutron Tube Target Loading Operations. Final document  

SciTech Connect

Neutron Tube Target Loading (NTTL) is an operation that involves the transferring (i.e. loading) of radioactive tritium gas onto metal target disks under an inert nitrogen atmosphere using a glovebox operation. The relocation of NTTL operations from the Pinellas Plant to the Los Alamos National Laboratory (LANL) in Los Alamos, New Mexico, was addressed in the Non-nuclear Consolidation Environmental Assessment (EA) of June 1993. This EA analyzes a Proposed Action to relocate the NTTL operations at LANL from Building 209 at TA-21 to Building 450 at TA-16. The Proposed Action would require the remodeling of Building 450 and some modifications to Buildings 205 and 205A, collectively referred to as the Weapons Engineering Tritium Facility (WETF) in TA-16. The construction of a change room addition would also be required to connect Building 450 and the WETF to take advantage of existing tritium control and confinement systems. Other construction activities and site modifications would include a new electrical substation, a new mechanical and electrical room, minor demolition work, two additional transportable buildings and a new parking area. An alternative to the Proposed Action includes keeping the NTTL operations at TA-21 (No Action). Alternatives considered but dismissed include the construction of a new NTTL laboratory at LANL, and the renovation of an alternative facility to Building 450 for conducting NTTL operations. None of the alternatives would enable the DOE to meet its mission responsibilities at LANL in a timely manner. The principle environmental issues associated with the Proposed Action include a minor amount of air emissions associated with construction activities and tritium operations and a small quantity of construction and low-level radioactive wastes. Human health and cumulative effects are expected to be negligible. On-site transportation of tritium between TA-21 and TA-16 to support NTTL operations would be eliminated.

NONE

1995-12-11T23:59:59.000Z

3

Neutron producing target for accelerator based neutron source for  

E-Print Network (OSTI)

247 Neutron producing target for accelerator based neutron source for NCT V. Belov1 , S. Fadeev1, Russia Summary Neutron producing targets for novel accelerator based neutron source [1, 2] are presented Neutron producing target is one of the main elements of proposed accelerator based facility for neutron

Taskaev, Sergey Yur'evich

4

Horizontal Beam Tubes - HFIR Technical Parameters | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Horizontal Beam Tubes Horizontal Beam Tubes The reactor has four horizontal beam tubes that supply the neutrons to the neutron scattering instruments. Details for each beam tube and instrument can be found on the HFIR instrument page. Each of the beam tubes that supply these instruments with neutrons is described subsequently. HB-1 and HB-3 The HB-1 and HB-3 thermal neutron beam tube designs are identical except for the length. Both are situated tangential to the reactor core so that the tubes point at reflector material and do not point directly at the fuel. An internal collimator is installed at the outboard end. This collimator is fabricated out of carbon steel and is plated with nickel. The collimator provides a 2.75-in by 5.5-in. rectangular aperture. A rotary shutter is located outboard of each of these beam tubes. The

5

High-voltage supply for neutron tubes in well-logging applications  

DOE Patents (OSTI)

A high voltage supply is provided for a neutron tube used in well logging. The biased pulse supply of the invention combines DC and full pulse techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

Humphreys, D.R.

1982-09-15T23:59:59.000Z

6

Uranium Neutron Coincidence Collar Model Utilizing Boron-10 Lined Tubes  

SciTech Connect

The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report, providing results for model development of Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) designs, is a deliverable under Task 2 of the project.

Rogers, Jeremy L.; Ely, James H.; Kouzes, Richard T.; Lintereur, Azaree T.; Siciliano, Edward R.

2012-09-18T23:59:59.000Z

7

KORONA; An intense sealed-tube 14-MeV neutron generator  

SciTech Connect

This paper describes a sealed-tube, high-current, low-energy accelerator (190 kV, 150 mA) in operation at the GKSS Research Center since 1981. The deuterium-tritium reaction yields a total source strength of 3 {times} 10 {sup 12} n/s. The neutron flux in the center of the hollow cylinder target is {approx} 3 {times} 10 n/cm{sup 2} {center dot} s in a 4-cm{sup 3} volume. Numerous 14-MeV neutron reaction cross sections have been determined with satisfactory accuracy; however, the system has been mainly used for neutron activation analysis. To predict the gamma-ray activity of any element after short-term irradiation with 14-MeV neutrons, a sensitivity study was performed, which proved to be a useful tool for analyzing complex spectra.

Pepelnik, R.; Fanger, H.U.; Michaelis, W. (GKSS-Forschungszentrum Geesthacht GmbH, Inst. fur Physik, Postfach 1160, D-2054 Geesthacht (DE))

1990-11-01T23:59:59.000Z

8

Neutron single target spin asymmetries in SIDIS  

SciTech Connect

The experiment E06-010 in Hall A at Jefferson Lab took data between November 2008 and February 2009 to directly measure, for the first time, the pion (and kaon) single "neutron" target-spin asymmetry (SSA) in semi-inclusive DIS from a polarized 3He target. Collins, Sivers (and Pretzelosity) neutron asymmetries are going to be extracted from the measured SSA. Details of the experiment are described together with the preliminary results of the ongoing analysis. Near future Hall A experiments on transverse nucleon spin structure are shorty reviewed.

Evaristo Cisbani

2010-04-01T23:59:59.000Z

9

A neutron producing target for BINP accelerator-based neutron source B. Bayanova  

E-Print Network (OSTI)

A neutron producing target for BINP accelerator-based neutron source B. Bayanova , E. Kashaeva b l e i n f o Keywords: Target Lithium Neutron capture therapy Epithermal neutrons a b s t r a c t An innovative accelerator-based neutron source for BNCT has just started operation at the Budker Institute

Taskaev, Sergey Yur'evich

10

Project of Rotating Carbon High-Power Neutron Target. Research of Graphite Properties for Production of High Intensity Neutron Source  

E-Print Network (OSTI)

Project of Rotating Carbon High-Power Neutron Target. Research of Graphite Properties for Production of High Intensity Neutron Source

Gubin, K V; Bak, P A; Kot, N K; Logatchev, P V

2001-01-01T23:59:59.000Z

11

Neutron Scattering Application of Polarized Solid Target in Materials Research  

SciTech Connect

Neutron scattering is one of the most important tools for materials research. However, neutrons are very expensive to produce. Even with the best sources, such as the newly completed Spallation Neutron Source at the Oak Ridge National Laboratory, most neutron scattering experiments are still flux limited. One way to improve the experimental data is polarized neutron scattering from polarized solid target: the strong spin-dependent neutron scattering cross-section can increase the coherent scattering and decrease the incoherent scattering at the same time, thereby significantly enhancing the signal to noise ratio. Hydrogen, abundant in most soft condensed matters, has a strong spin-dependent scattering cross-section. Early applications of polarized neutron scattering in biological soft condensed matters have already demonstrated the huge potential of this technique. Here we describe the polarized target program at the SNS. The program is under active construction and is aimed at serving neutron scattering at the SNS.

Zhao, Jinkui [ORNL

2008-09-01T23:59:59.000Z

12

HEATING DISTRIBUTIONS IN THE TARGET OF THE SPALLATION NEUTRON...  

Office of Scientific and Technical Information (OSTI)

IN THE TARGET OF THE SPALLATION NEUTRON SOURCE F. C. Difilippo and L. A. Charlton Oak Ridge National Laboratory* P.O. Box 2008, MS-6363 Oak Ridge, Tennessee 3783 l-6363...

13

Boron-Lined Straw-Tube Neutron Detector Test  

SciTech Connect

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. Reported here are the results of tests of a boron-lined proportional counter design variation. In the testing described here, the neutron detection efficiency and gamma ray rejection capabilities of a system manufactured by Proportional Technologies, Inc, was tested.

Kouzes, Richard T.; Ely, James H.; Stromswold, David C.

2010-08-07T23:59:59.000Z

14

Thick-Target Neutron Yield from the 19F(alpha,n) Reaction  

E-Print Network (OSTI)

Thick-target neutron yields from the 19F(alpha,n) reaction are reported for E(alpha) = 3.5 - 10.0 MeV.

E. B. Norman; T. E. Chupp; K. T. Lesko; G. L. Woodruff; P. J. Grant

2014-11-01T23:59:59.000Z

15

Thick-Target Neutron Yield from the 19F(alpha,n) Reaction  

E-Print Network (OSTI)

Thick-target neutron yields from the 19F(alpha,n) reaction are reported for E(alpha) = 3.5 - 10.0 MeV.

Norman, E B; Lesko, K T; Woodruff, G L; Grant, P J

2014-01-01T23:59:59.000Z

16

Neutron diffraction determination of the residual stress redistribution in cracked autofrettaged tubing  

SciTech Connect

Neutron diffraction has been used to measure the residual stress distributions in uncracked and fatigue cracked rings taken from a high strength, low alloy steel autofrettage tube with a bore diameter of 60mm and a wall thickness of 32mm. Stresses were determined to a precision of {plus minus} 10MPa. Three crack sixes were examines. No appreciable stress redistribution was observed until the crack was grown into a region which originally contained tensile residual hoop stress. When this occurred an increase in residual hoop tension was observed ahead of the crick tip. Qualitative agreement was achieved between the measured hoop stress distribution and values predicted using a boundary element method. 9 refs., 12 figs.

Bourke, M.A. (Los Alamos National Lab., NM (USA)); McGillivray, H.J.; Webster, G.A. (Imperial Coll. of Science, Technology and Medicine, London (UK). Dept. of Mechanical Engineering); Webster, P.J. (Salford Univ. (UK). Dept. of Civil Engineering)

1991-01-01T23:59:59.000Z

17

Accelerator-based neutron source using a cold deuterium target with degenerate electrons  

SciTech Connect

A neutron generator is considered in which a beam of tritons is incident on a hypothetical cold deuterium target with degenerate electrons. The energy efficiency of neutron generation is found to increase substantially with electron density. Recent reports of potential targets are discussed.

Phillips, R. E.; Ordonez, C. A. [Department of Physics, University of North Texas, Denton, Texas 76203 (United States)] [Department of Physics, University of North Texas, Denton, Texas 76203 (United States)

2013-07-15T23:59:59.000Z

18

Comparisons on thin and thick neutron target for low energy proton beam  

SciTech Connect

As the progress on accelerator physics and neutronics, the compact neutron sources driven by low energy and high intensity beam are becoming extensively developed and researched all around the world. The neutron target of an accelerator driven neutron source is one of the key components, and the stability of the neutron target affect the operation and performance of the neutron facility. When a low energy proton is projected to the beryllium target, the main reaction is the inelastic scattering between the proton and extra-nuclear electrons. As the decreasing of proton energy, the rate of elastic scattering between proton and target nucleus begins to increase. When the energy of proton is very low, the pickup charge reaction begins to appear. Focus on the problems brought by high intensity proton beam such as proton implantation, radiation damages, heat deposition and gas production, we performed sufficient numerical simulations for both thin and thick target determined by proton range. The results show that the critical problem for thick target is the proton implantation, causing the forming of bubbles and beryllium flaked in vacuum. The thin target sacrifices a little neutron yield, but avoid the proton stopped in target, and decrease the radiation damage and energy deposition. (authors)

Zhong, B.; Yu, G.; Wang, X.; Wang, K. [Dept. of Engineering Physics, Tsinghua Univ., Beijing 100084 (China)

2012-07-01T23:59:59.000Z

19

Targeted chlorination for biofouling control in steam electric power plant condenser tubes  

SciTech Connect

The objective of this study was to develop an understanding of the relationships between biofouling, heat transfer, and to assess the technical feasibility of the targeted chlorination (TC) concept as an alternative to conventional chlorination in once-through seawater cooling systems. A shell and tube type heat exchanger was designed and constructed. The test facility monitored biofouling growth by measuring heat transfer resistance (thermal performance), pressure drop (hydraulic performance), and biomass deposit. Biocide effectiveness was determined by triplicates average residual biomass. Tests were run to evaluate 18 treatment scenarios. Preliminary tests were done to determine variabilities between shells and among tubes, effect of heating, very high dose chlorine burn out and regrowth behavior. LOGIT, a software package by the National Bureau of Standards (NBS) for sigmoidal fit, was used for the preliminary test data. The other three tests studied effect of chlorine dosage (low, high), contact time, and frequency. To minimize variability in results, triplicates for each chlorination scheme were used. The total amount of chlorine applied (flow rate Q x C x T x F) ranged from about 400 to 4,000 pounds per million gallons per day (an equivalent to a CTF range of 6 to 60 ppm.min/day). With respect to efficiency of biofouling control, it was found by regression analysis that among four variables C, T, (CT) and F, F was most significant and C, T, and (CT) were relatively equal in ranking.

Tewari, R.N.

1991-01-01T23:59:59.000Z

20

Neutron measurements from beam-target reactions at the ELISE neutral beam test facility  

SciTech Connect

Measurements of 2.5 MeV neutron emission from beam-target reactions performed at the ELISE neutral beam test facility are presented in this paper. The measurements are used to study the penetration of a deuterium beam in a copper dump, based on the observation of the time evolution of the neutron counting rate from beam-target reactions with a liquid scintillation detector. A calculation based on a local mixing model of deuterium deposition in the target up to a concentration of 20% at saturation is used to evaluate the expected neutron yield for comparison with data. The results are of relevance to understand neutron emission associated to beam penetration in a solid target, with applications to diagnostic systems for the SPIDER and MITICA Neutral Beam Injection prototypes.

Xufei, X., E-mail: xiexufei@pku.edu.cn; Fan, T. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Nocente, M.; Gorini, G. [Dipartimento di Fisica “G. Occhialini”, Università di Milano-Bicocca, Milano 20216 (Italy); Istituto di Fisica del Plasma “P. Caldirola”, Milano 20216 (Italy); Bonomo, F. [Consorzio RFX, Padova 35100 (Italy); Istituto Gas Ionizzati, CNR, Padova 35100 (Italy); Franzen, P.; Fröschle, M. [Max-Planck-Institut für Plasmaphysik, Garching 84518 (Germany); Grosso, G.; Tardocchi, M. [Istituto di Fisica del Plasma “P. Caldirola”, Milano 20216 (Italy); Grünauer, F. [Physics Consulting, Zorneding 85604 (Germany); Pasqualotto, R. [Consorzio RFX, Padova 35100 (Italy)

2014-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

WATER PURITY DEVELOPMENT FOR THE COUPLED CAVITY LINAC (CCL) AND DRIFT TUBE LINAC (DTL) STRUCTURES OF THE SPALLATION NEUTRON SOURCE (SNS) LINAC  

SciTech Connect

The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. SNS will generate and use neutrons as a diagnostic tool for medical purposes, material science, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of two room temperature copper structures, the drift tube linac (DTL), and the coupled cavity linac (CCL). Both of these accelerating structures use large amounts of electrical energy to accelerate the proton beam. Approximately 60-80% of the electrical energy is dissipated in the copper structure and must be removed. This is done using specifically designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by specially designed resonance control and water cooling systems. One of the primary components in the DTL and CCL water cooling systems, is a water purification system that is responsible for minimizing erosion, corrosion, scaling, biological growth, and hardware activation. The water purification system consists of filters, ion exchange resins, carbon beds, an oxygen scavenger, a UV source, and diagnostic instrumentation. This paper reviews related issues associated with water purification and describes the mechanical design of the SNS Linac water purification system.

D. KATONAK; J. BERNARDIN; S. HOPKINS

2001-06-01T23:59:59.000Z

22

The national spallation neutron source target station: A general overview  

SciTech Connect

The technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the National Spallation Neutron Source (NSNS), are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis and the planned hardware research and development program are also described.

Gabriel, T.A.; Barnes, J.N.; Charlton, L.A. [and others

1997-06-01T23:59:59.000Z

23

HFIR Experiment Facilities | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Experiment Facilities Experiment Facilities HFIR Experiment Facilities Neutron Scattering Facilities Target Positions Experiment Facilities in the Beryllium Reflector Large Removable Beryllium Facilities Small Removable Beryllium Facilities Control-Rod Access Plug Facilities Small Vertical Experiment Facilities Large Vertical Experiment Facilities Hydraulic Tube Facility Peripheral Target Positions Neutron Activation Analysis (NAA) Laboratory and Pneumatic Tube Facilities Slant Engineering Facilities Gamma Irradiation Facility Quality Assurance Requirements Contact Information Neutron Scattering Facilities The fully instrumented HFIR will eventually include 15 state-of-the-art neutron scattering instruments, seven of which will be designed exclusively for cold neutron experiments, located in a guide hall south of the reactor

24

Cyclotrons to Make Neutrons & Radioactive Targets for SBSS at LBNL | U.S.  

Office of Science (SC) Website

Cyclotrons to Make Neutrons & Cyclotrons to Make Neutrons & Radioactive Targets for SBSS at LBNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives Cyclotrons to Make Neutrons & Radioactive Targets for SBSS at LBNL Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Use of cyclotrons for producing neutrons & radioactive targets for

25

Influence of prepulse plasma formation on neutron production from the laser-target interaction  

SciTech Connect

The interaction of an intense ultrashort pulse laser with a planar uniform target was studied with a two-dimensional relativistic electromagnetic particle-in-cell method to determine the acceleration of deuterons and production of neutrons. A Au-CD{sub 2} double-layer planar target with thickness of {approx}1 {mu}m and a preplasma of variable length was used to generate high-energy deuterons as a precursor for neutron production. The deuteron energy and angular distributions and the neutron production from D(d,n)-{sup 3}He nuclear fusion reactions were studied as a function of the preplasma scale length and target thickness. For very thin (submicron) targets the preplasma increases the neutron yield only marginally, but for realistic targets with thickness of a few microns the preplasma enhances the neutron yield by two orders of magnitude. Both the average deuteron energy and neutron yield peak at an optimum preplasma scale length L{sub p}{sup opt}{approx_equal}1/k{sub 0} (k{sub 0} laser wave vector), which is of the order of one inverse laser wave vector.

Davis, J.; Petrov, G. M. [Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)

2008-08-15T23:59:59.000Z

26

Neutron energy spectrum from 120 GeV protons on a thick copper target  

E-Print Network (OSTI)

Neutron energy spectrum from 120 GeV protons on a thick copper target was measured at the Meson Test Beam Facility (MTBF) at Fermi National Accelerator Laboratory. The data allows for evaluation of neutron production process implemented in theoretical simulation codes. It also helps exploring the reasons for some disagreement between calculation results and shielding benchmark data taken at high energy accelerator facilities, since it is evaluated separately from neutron transport. The experiment was carried out using a 120 GeV proton beam of 3E5 protons/spill. Since the spill duration was 4 seconds, proton-induced events were counted pulse by pulse. The intensity was maintained using diffusers and collimators installed in the beam line to MTBF. The protons hit a copper block target the size of which is 5cm x 5cm x 60 cm long. The neutrons produced in the target were measured using NE213 liquid scintillator detectors, placed about 5.5 m away from the target at 30^{\\circ} and 5 m 90^{\\circ} with respect to the proton beam axis. The neutron energy was determined by time-of-flight technique using timing difference between the NE213 and a plastic scintillator located just before the target. Neutron detection efficiency of NE213 was determined on basis of experimental data from the high energy neutron beam line at Los Alamos National Laboratory. The neutron spectrum was compared with the results of multi-particle transport codes to validate the implemented theoretical models. The apparatus would be applied to future measurements to obtain a systematic data set for secondary particle production on various target materials.

Nobuhiro Shigyo; Toshiya Sanami; Tsuyoshi Kajimoto; Yosuke Iwamoto; Masayuki Hagiwara; Kiwamu Saito; Kenji Ishibashi; Hiroshi Nakashima; Yukio Sakamoto; Hee-Seock Lee; Erik Ramberg; Aria A. Meyhoefer; Rick Coleman; Doug Jensen; Anthony F. Leveling; David J. Boehnlein; Nikolai V. Mokhov

2012-02-07T23:59:59.000Z

27

NAPTH: Neutronics analysis code system for the fusion–fission hybrid reactor with pressure tube type blanket  

Science Journals Connector (OSTI)

The fusion–fission hybrid reactor is considered as a potential path to the early application of fusion energy. A new concept with pressure tube type blanket has recently been proposed for a feasible hybrid reactor. In this paper, a code system for the neutronics analysis of the pressure tube type hybrid reactor is developed based on the two-step calculation scheme: the few-group homogeneous constant calculation and the full blanket calculation. The few-group homogeneous constants are calculated using the lattice code DRAGON4. The blanket transport calculation is performed by the multigroup Monte Carlo code. A link procedure for fitting the cross sections is developed between these two steps. An additional procedure is developed to calculate the burnup, power distribution, energy multiplication factor, tritium breeding ratio and neutron multiplication factor. From some numerical results, it is found that the code system NAPTH is reliable and exhibits good calculation efficiency. It can be used for the conceptual design of the pressure tube type hybrid reactor with precise geometry.

Tiejun Zu; Hongchun Wu; Youqi Zheng; Liangzhi Cao; Chao Yang

2013-01-01T23:59:59.000Z

28

Fast neutron emission from a deuterated polystyrene solid target irradiated by a high-intensity laser pulse  

Science Journals Connector (OSTI)

Fast neutrons were generated from a deuterated polystyrene (C8D8) solid-target irradiated by a high-intensity laser. A TOF neutron signal is analyzed in detail. A...

Lee, Sungman; Kwon, Sungok; Lee, Kitae; Cha, Yong-Ho; Yea, Kwon-hae; Lee, Yong Woo; Lee, Ji Young; Jeong, Young Uk; Rhee, Yong Joo; Cha, Hyungki

29

Fast neutron emission from a deuterated polystyrene solid target irradiated by a high-intensity laser pulse  

Science Journals Connector (OSTI)

Fast neutrons were generated from a deuterated polystyrene (C8D8) solid-target irradiated by a high-intensity laser. A TOF neutron signal is analyzed in detail....

Lee, Sungman; Kwon, Sungok; Lee, Kitae; Cha, Yong-Ho; Yea, Kwon-hae; Lee, Yong Woo; Lee, Ji Young; Jeong, Young Uk; Rhee, Yong Joo; Cha, Hyungki

30

Synthesis of neutron-rich transuranic nuclei in fissile spallation targets  

E-Print Network (OSTI)

A possibility of synthesizing neutron-reach super-heavy elements in spallation targets of Accelerator Driven Systems (ADS) is considered. A dedicated software called Nuclide Composition Dynamics (NuCoD) was developed to model the evolution of isotope composition in the targets during a long-time irradiation by intense proton and deuteron beams. Simulation results show that transuranic elements up to Bk-249 can be produced in multiple neutron capture reactions in macroscopic quantities. However, the neutron flux achievable in a spallation target is still insufficient to overcome the so-called fermium gap. Further optimization of the target design, in particular, by including moderating material and covering it by a reflector will turn ADS into an alternative source of transuranic elements in addition to nuclear fission reactors.

Mishustin, Igor; Pshenichnov, Igor; Greiner, Walter

2014-01-01T23:59:59.000Z

31

Neutron production using a pyroelectric driven target coupled with a gated field ionization source  

SciTech Connect

A palm sized, portable neutron source would be useful for widespread implementation of detection systems for shielded, special nuclear material. We present progress towards the development of the components for an ultracompact neutron generator using a pulsed, meso-scale field ionization source, a deuterated (or tritiated) titanium target driven by a negative high voltage lithium tantalate crystal. Neutron production from integrated tests using an ion source with a single, biased tungsten tip and a 3 Multiplication-Sign 1 cm, vacuum insulated crystal with a plastic deuterated target are presented. Component testing of the ion source with a single tip produces up to 3 nA of current. Dielectric insulation of the lithium tantalate crystals appears to reduce flashover, which should improve the robustness. The field emission losses from a 3 cm diameter crystal with a plastic target and 6 cm diameter crystal with a metal target are compared.

Ellsworth, J. L.; Tang, V.; Falabella, S. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Naranjo, B.; Putterman, S. [University of California Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095 (United States)

2013-04-19T23:59:59.000Z

32

Three-dimensional calculations of neutron streaming in the beam tubes of the ORNL HFIR (High Flux Isotope Reactor) Reactor  

SciTech Connect

The streaming of neutrons through the beam tubes in High Flux Isotope Reactor at Oak Ridge National Laboratory has resulted in a reduction of the fracture toughness of the reactor vessel. As a result, an evaluation of vessel integrity was undertaken in order to determine if the reactor can be operated again. As a part of this evaluation, three-dimensional neutron transport calculations were performed to obtain fluxes at points of interest in the wall of the vessel. By comparing the calculated and measured activation of dosimetry specimens from the vessel surveillance program, it was determined that the calculated flux shape was satisfactory to transpose the surveillance data to the locations in the vessel. A bias factor was applied to correct for the average C/E ratio of 0.69. 8 refs., 7 figs., 3 tabs.

Childs, R.L.; Rhoades, W.A.; Williams, L.R.

1988-01-01T23:59:59.000Z

33

Prototype Spallation Neutron Source Rotating Target Assembly Final Test Report  

SciTech Connect

A full-scale prototype of an extended vertical shaft, rotating target assembly based on a conceptual target design for a 1 to 3-MW spallation facility was built and tested. Key elements of the drive/coupling assembly implemented in the prototype include high integrity dynamic face seals, commercially available bearings, realistic manufacturing tolerances, effective monitoring and controls, and fail-safe shutdown features. A representative target disk suspended on a 3.5 meter prototypical shaft was coupled with the drive to complete the mechanical tests. Successful operation for 5400 hours confirmed the overall mechanical feasibility of the extended vertical shaft rotating target concept. The prototype system showed no indications of performance deterioration and the equipment did not require maintenance or relubrication.

McManamy, Thomas J [ORNL; Graves, Van [Oak Ridge National Laboratory (ORNL); Garmendia, Amaia Zarraoa [IDOM Bilbao; Sorda, Fernando [ESS Bilbao; Etxeita, Borja [IDOM Bilbao; Rennich, Mark J [ORNL

2011-01-01T23:59:59.000Z

34

Final Environmental Assessment for the Proposed Consolidation of Neutron Generator Tritium Target Loading Production  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Final Environmental Assessment Final Environmental Assessment for the Proposed Consolidation of Neutron Generator Tritium Target Loading Production DOE/EA-1532 June 2005 National Nuclear Security Administration Sandia Site Office P.O. Box 5400 Albuquerque, New Mexico 87185-5400 Environmental Assessment for the Proposed Consolidation of Neutron Generator Tritium Target Loading Production i Final EA DOE/EA-1532 June 2005 TABLE OF CONTENTS 1.0 PURPOSE AND NEED FOR AGENCY ACTION ........................................................................ 1 2.0 NO ACTION AND PROPOSED ACTION ALTERNATIVES...................................................... 2 2.1 No Action Alternative....................................................................................... 5

35

Dynamically polarized hydrogen target as a broadband, wavelength-independent thermal neutron spin polarizer  

SciTech Connect

A hydrogen-rich sample with dynamically polarized hydrogen nuclei was tested as a wavelength-independent neutron transmission spin polarizer. The experiment used a modified setup of the dynamic nuclear polarization target station at the GKSS research center. The standard solvent sample at the GKSS DNP station was used. It is 2.8 mm thick and consists of 43.4 wt% water, 54.6 wt% glycerol, and 2 wt% of EHBA-Cr(v) complex. The wavelength of the incident neutrons for the transmission experiment was {lambda} = 8.1 {angstrom} with {Delta}{lambda}/{lambda} = 10%. The polarization of neutron beam after the target sample was analyzed with a supermirror analyzer. A neutron polarization of -52% was achieved at the hydrogen polarization of -69%. Further experiments will test the feasibility of other hydrogen-rich materials, such as methane, as the polarizer. A theoretical calculation shows that a polarized methane target would allow over 95% neutron polarizations with more than 30% transmission.

Zhao, Jinkui [ORNL; Garamus, VM [GKSS Research Center, Germany; Mueller, W [GKSS Research Center, Germany; Willumeit, R [GKSS Research Center, Germany

2005-01-01T23:59:59.000Z

36

Neutron guide  

DOE Patents (OSTI)

A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

Greene, Geoffrey L. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

37

Fast neutron scattering on Gallium target at 14.8 MeV  

E-Print Network (OSTI)

Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

Han, R; Chen, Z; Nie, Y; Liu, X; Zhang, S; Ren, P; Jia, B; Tian, G; Luo, F; Lin, W; Liu, J; Shi, F; Huang, M; Ruan, X; Ren, J; Zhou, Z; Huang, H; Bao, J; Zhang, K; Hu, B

2014-01-01T23:59:59.000Z

38

Fast neutron scattering on Gallium target at 14.8 MeV  

E-Print Network (OSTI)

Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

R. Han; R. Wada; Z. Chen; Y. Nie; X. Liu; S. Zhang; P. Ren; B. Jia; G. Tian; F. Luo; W. Lin; J. Liu; F. Shi; M. Huang; X. Ruan; J. Ren; Z. Zhou; H. Huang; J. Bao; K. Zhang; B. Hu

2014-11-03T23:59:59.000Z

39

Neutron production from 7Li(d,xn) nuclear fusion reactions driven by high-intensity laser–target interactions  

Science Journals Connector (OSTI)

Numerical simulations of neutron production from deuterium–lithium nuclear fusion reactions have been performed. A set of differential cross sections for the 7Li(d,xn) reaction for incident deuteron energies of up to 50?MeV is assembled. The angular distribution of neutrons from a thick lithium target is simulated and benchmarked against experimental data. Two-stage neutron production from laser–target experiments has been studied as a function of laser intensity and energy. During the first stage a well collimated deuteron beam is generated using a high-intensity ultrashort pulse laser. During the second stage it is transported through a lithium target using a 3D Monte-Carlo ion beam–target deposition model. The neutron yield is estimated to be ~108?neutrons?J?1 laser energy. Some 1010 neutrons can be expected from a ~100?J petawatt-class laser. For incident deuteron energies above 1?MeV the proposed scheme for neutron production from d–Li reactions is superior to that from d–d reactions, producing a collimated beam of neutrons with higher neutron yield.

J Davis; G M Petrov; Tz Petrova; L Willingale; A Maksimchuk; K Krushelnick

2010-01-01T23:59:59.000Z

40

Nuclear Simulation and Radiation Physics Investigations of the Target Station of the European Spallation Neutron Source  

SciTech Connect

The European Spallation Neutron Source (ESS) delivers high-intensity pulsed particle beams with 5-MW average beam power at 1.3-GeV incident proton energy. This causes sophisticated demands on material and geometry choices and a very careful optimization of the whole target system. Therefore, complex and detailed particle transport models and computer code systems have been developed and used to study the nuclear assessment of the ESS target system. The purpose here is to describe the methods of calculation mainly based on the Monte Carlo code to show the performance of the ESS target station. The interesting results of the simulations of the mercury target system are as follows: time-dependent neutron flux densities, energy deposition and heating, radioactivity and afterheat, materials damage by radiation, and high-energy source shielding. The results are discussed in great detail. The validity of codes and models, further requirements to improve the methods of calculation, and the status of running and planned experiments are given also.

Filges, Detlef; Neef, Ralf-Dieter; Schaal, Hartwig [Forschungszentrum Juelich GmbH (Germany)

2000-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Neutron production from interactions of high-intensity ultrashort pulse laser with a planar deuterated polyethylene target  

SciTech Connect

The deuteron acceleration from a planar uniform deuterated polyethylene (CD{sub 2}) target was studied with a two-dimensional electromagnetic particle-in-cell method in the ultrarelativistic regime for peak laser intensities between 10{sup 23} and 10{sup 25} W/m{sup 2}. Under identical conditions the deuteron energy and angular distributions are very different when compared to that produced from a double-layer target. The neutron production from D(d,n)-{sup 3}He nuclear fusion reactions was also investigated with a three-dimensional Monte Carlo ion beam-target deposition model. The neutron yield and its angular distribution were studied as a function of peak laser intensity and laser pulse duration. A neutron yield of 10{sup 4}-10{sup 6} neutrons per Joule laser energy is inferred from simulations of a 4 {mu}m thick planar uniform CD{sub 2} target. The angular scattering of neutrons is found to be nonisotropic and has a significant component in the forward (laser propagation) direction.

Petrov, G. M.; Davis, J. [Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Avenue SW, Washington, D.C. 20375 (United States)

2008-07-15T23:59:59.000Z

42

Neutronic Assessment of Transmutation Target Compositions in Heterogeneous Sodium Fast Reactor Geometries  

SciTech Connect

The sodium fast reactor is under consideration for consuming the transuranic waste in the spent nuclear fuel generated by light water reactors. This work is concerned with specialized target assemblies for an oxide-fueled sodium fast reactor that are designed exclusively for burning the americium and higher mass actinide component of light water reactor spent nuclear fuel (SNF). The associated gamma and neutron radioactivity, as well as thermal heat, associated with decay of these actinides may significantly complicate fuel handling and fabrication of recycled fast reactor fuel. The objective of using targets is to isolate in a smaller number of assemblies these concentrations of higher actinides, thus reducing the volume of fuel having more rigorous handling requirements or a more complicated fabrication process. This is in contrast to homogeneous recycle where all recycled actinides are distributed among all fuel assemblies. Several heterogeneous core geometries were evaluated to determine the fewest target assemblies required to burn these actinides without violating a set of established fuel performance criteria. The DIF3D/REBUS code from Argonne National Laboratory was used to perform the core physics and accompanying fuel cycle calculations in support of this work. Using the REBUS code, each core design was evaluated at the equilibrium cycle condition.

Samuel E. Bays; Rodolfo M. Ferrer; Michael A. Pope; Benoit Forget; Mehdi Asgari

2008-02-01T23:59:59.000Z

43

Instrument performance study on the short and long pulse options of the second Spallation Neutron Source target station  

SciTech Connect

The Spallation Neutron Source (SNS) facility at the Oak Ridge National Laboratory is designed with an upgrade option for a future low repetition rate, long wavelength second target station. This second target station is intended to complement the scientific capabilities of the 1.4 MW, 60 Hz high power first target station. Two upgrade possibilities have been considered, the short and the long pulse options. In the short pulse mode, proton extraction occurs after the pulse compression in the accumulator ring. The proton pulse structure is thus the same as that for the first target station with a pulse width of ?0.7 ?s. In the long pulse mode, protons are extracted as they are produced by the linac, with no compression in the accumulator ring. The time width of the uncompressed proton pulse is ?1 ms. This difference in proton pulse structure means that neutron pulses will also be different. Neutron scattering instruments thus have to be designed and optimized very differently for these two source options which will directly impact the overall scientific capabilities of the SNS facility. In order to assess the merits of the short and long pulse target stations, we investigated a representative suit of neutron scattering instruments and evaluated their performance under each option. Our results indicate that the short pulse option will offer significantly better performance for the instruments and is the preferred choice for the SNS facility.

Zhao, J. K.; Herwig, Kenneth W.; Robertson, J. L.; Gallmeier, Franz X.; Riemer, Bernard W. [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2013-10-15T23:59:59.000Z

44

The neutron charge form factor and target analyzing powers from pol.3He(pol e,e'n)-scattering  

E-Print Network (OSTI)

The charge form factor of the neutron has been determined from asymmetries measured in quasi--elastic pol.3He(pol e,e'n) at a momentum transfer of 0.67(GeV/c)^2. In addition, the target analyzing power, A_y^o, has been measured to study effects of final state interactions and meson exchange currents.

J. Bermuth; P. Merle; C. C. Carasco; D. Baumann; R. Boehm; D. Bosnar; M. Ding; M. O. Distler; J. Friedrich; J. M Friedrich; J. Golak; W. Gloeckle; M. Hauger; W. Heil; P. Jennewein; J. Jourdan; H. Kamada; A. Klein; M. Kohl; B. Krusche; K. W. Krygier; H. Merkel; U. Mueller; R. Neuhausen; A. Nogga; Ch. Normand; E. Otten; Th. Pospischil; M. Potokar; D. Rohe; H. Schmieden; J. Schmiedeskamp; M. Seimetz; I. Sick; S. Sirca; S. Skibinski; G. Testa; Th. Walcher; G. Warren; M. Weis; H. Witala; H. Woehrle; M. Zeier

2003-03-27T23:59:59.000Z

45

Combination of the vascular targeting agent ZD6126 with boron neutron capture therapy  

SciTech Connect

Purpose: The aim of this study was to evaluate the antitumor efficacy of the vascular targeting agent ZD6126 (N-acetylcochinol-O-phosphate) in the rodent squamous cell carcinoma (SCC) VII carcinoma model, in combination with boron neutron capture therapy (BNCT). Methods and materials: Sodium borocaptate-{sup 10}B (BSH, 125 mg/kg, i.p.) or l-p-boronophenylalanine-{sup 10}B (BPA, 250 mg/kg, i.p.) was injected into SCC VII tumor-bearing mice, and 15 min later, ZD6126 (100 mg/kg, i.p.) was administered. Then, the {sup 10}B concentrations in tumors and normal tissues were measured by prompt {gamma}-ray spectrometry. On the other hand, for the thermal neutron beam exposure experiment, SCC VII tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumors, followed by treatment with a {sup 10}B-carrier and ZD6126 in the same manner as the above-mentioned {sup 10}B pharmacokinetics analyses. To obtain almost similar intratumor {sup 10}B concentrations during neutron exposure, thermal neutron beam irradiation was started from the time point of 30 min after injection of BSH only, 90 min after BSH injection for combination with ZD6126, 120 min after the injection of BPA only, and 180 min after BPA injection for combination with ZD6126. Right after irradiation, the tumors were excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling (quiescent [Q] cells) was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. The clonogenic cell survival assay was also performed in mice given no BrdU. Results: Pharmacokinetics analyses showed that combination with ZD6126 greatly increased the {sup 10}B concentrations in tumors after 60 min after BSH injection and after 120 min after BPA injection. The concentrations of {sup 10}B from BSH in normal tissues were also raised by combination with ZD6126, although not so clearly as those in tumors. Combination with ZD6126 had almost no effect on the concentrations of {sup 10}B from BPA in normal tissues. The clonogenic surviving fractions of total tumor cells and the MN frequencies of both total and Q tumor cells were reduced and increased by combination with ZD6126, respectively, whether BSH or BPA was employed. However, the degrees of these changes in the clonogenic surviving fractions and the MN frequencies were more obviously observed in tumors from BSH-injected mice than from BPA-injected mice, and in Q tumor cells than in total tumor cells regardless of the employed {sup 10}B-carrier. Conclusions: Combination with ZD6126 was regarded as more promising in BSH-BNCT than BPA-BNCT, and more effective for enhancing the sensitivity of the Q tumor cells than that of the total tumor cells. This resulted in the decrease in the extended difference in the sensitivity between the total and Q tumor cells caused by the use of {sup 10}B-carrier for BNCT.

Masunaga, Shin-ichiro [Radiation Oncology Research Laboratory, Research Reactor Institute, Kyoto University, Osaka (Japan)]. E-mail: smasuna@rri.kyoto-u.ac.jp; Sakurai, Yoshinori [Division of Radiation Life Science, Research Reactor Institute, Kyoto University, Osaka (Japan); Suzuki, Minoru [Radiation Oncology Research Laboratory, Research Reactor Institute, Kyoto University, Osaka (Japan); Nagata, Kenji [Radiation Oncology Research Laboratory, Research Reactor Institute, Kyoto University, Osaka (Japan); Maruhashi, Akira [Division of Radiation Life Science, Research Reactor Institute, Kyoto University, Osaka (Japan); Kinash, Yuko [Division of Radiation Safety, Research Reactor Institute, Kyoto University, Osaka (Japan); Ono, Koji [Radiation Oncology Research Laboratory, Research Reactor Institute, Kyoto University, Osaka (Japan)

2004-11-01T23:59:59.000Z

46

IPNS enriched uranium booster target  

SciTech Connect

Since startup in 1981, IPNS has operated on a fully depleted /sup 238/U target. With the booster as in the present system, high energy protons accelerated to 450 MeV by the Rapid Cycling Synchrotron are directed at the target and by mechanisms of spallation and fission of the uranium, produce fast neutrons. The neutrons from the target pass into adjacent moderator where they slow down to energies useful for spectroscopy. The target cooling systems and monitoring systems have operated very reliably and safely during this period. To provide higher neutron intensity, we have developed plans for an enriched uranium (booster) target. HETC-VIM calculations indicate that the target will produce approx.90 kW of heat, with a nominal x5 gain (k/sub eff/ = 0.80). The neutron beam intensity gain will be a factor of approx.3. Thermal-hydraulic and heat transport calculations indicate that approx.1/2 in. thick /sup 235/U discs are subject to about the same temperatures as the present /sup 238/U 1 in. thick discs. The coolant will be light demineralized water (H/sub 2/O) and the coolant flow rate must be doubled. The broadening of the fast neutron pulse width should not seriously affect the neutron scattering experiments. Delayed neutrons will appear at a level about 3% of the total (currently approx.0.5%). This may affect backgrounds in some experiments, so that we are assessing measures to control and correct for this (e.g., beam tube choppers). Safety analyses and neutronic calculations are nearing completion. Construction of the /sup 235/U discs at the ORNL Y-12 facility is scheduled to begin late 1985. The completion of the booster target and operation are scheduled for late 1986. No enriched uranium target assembly operating at the projected power level now exists in the world. This effort thus represents an important technological experiment as well as being a ''flux enhancer''.

Schulke, A.W. Jr.

1985-01-01T23:59:59.000Z

47

Testing of T-odd, P-even interactions by nonpolarized neutron transmission through a nonpolarized nuclear target placed into electric field  

E-Print Network (OSTI)

A new possibility for the study of time-reversal violation is described. It consists in measurement of nonpolarized neutron transmission through nonpolarized nuclear target placed into electric field

V. G. Baryshevsky

2003-12-01T23:59:59.000Z

48

Design of a TOF-SANS instrument for the proposed Long Wavelength Target Station at the Spallation Neutron Source.  

SciTech Connect

We have designed a versatile high-throughput SANS instrument [Broad Range Intense Multipurpose SANS (BRIMS)] for the proposed Long Wavelength Target Station at the SNS by using acceptance diagrams and the Los Alamos NISP Monte Carlo simulation package. This instrument has been fully optimized to take advantage of the 10 Hz source frequency (broad wavelength bandwidth) and the cold neutron spectrum from a tall coupled solid methane moderator (12 cm x 20 cm). BRIMS has been designed to produce data in a Q range spanning from 0.001 to 0.7 {angstrom}{sup {minus}1} in a single measurement by simultaneously using neutrons with wavelengths ranging from 1 to 14.5 {angstrom} in a time of flight mode. A supermirror guide and bender assembly is employed to separate and redirect the useful portion of the neutron spectrum with {lambda} > 1 {angstrom}, by 2.3{degree} away from the direct beam containing high energy neutrons and {gamma} rays. The effects of the supermirror coating of the guide, the location of the bender assembly with respect to the source, the bend angle, and various collimation choices on the flux, resolution and Q{sub min} have been characterized using spherical particle and delta function scatterers. The overall performance of BRIMS has been compared with that of the best existing reactor-based SANS instrument D22 at ILL.

Thiyagarajan, P.; Littrell, K.; Seeger, P. A.

2000-11-28T23:59:59.000Z

49

Accelerator-based neutron brachytherapy  

Science Journals Connector (OSTI)

The development and evaluation of a new approach to neutronbrachytherapy is described. This approach accelerator-based fast neutronbrachytherapy involves the interstitial or intracavity insertion of a narrow evacuated accelerator beam tube such that its tip containing the neutron-producing target is placed in or near the tumor.Tumorirradiation via brachytherapy should result in a reduction in the healthy tissue complication rate observed when poorly collimated and/or low energy external neutron beam are used for treatment. Use of a variable energy accelerator provides an advantage over isotopesources for neutronbrachytherapy in that the neutron beam can be turned on and off and the neutronenergy spectrum varied for different treatment applications. A prototype accelerator-based fast neutronbrachytherapy device 10 cm long and 6 mm outer diameter has been constructed and evaluated in terms of its dosimetric output treatment time and practical feasibility. The prototype device is a tube-in-tube design with cooling water running between the inner and outer tubes to cool a beryllium target located at the tip of the inner tube. Cooling experiments were performed and coupled with Monte Carlo simulations to determine treatment times as a function of heat load for various neutron-producing reactions. Using the 9 Be (d n) 10 B reaction at E d =1.5 MeV 66 RBE-Gy (12 Gy physical dose) can be delivered to the boundary of a 4.5-cm-diam treatment volume in 8 min at a heat load of 130 W. Other reactions offer similar treatment times at somewhat higher bombarding energies and also show higher potential for dose enhancement with the boron-10 neutron capture reaction due to their softer neutron spectra. Dose distributions in a water phantom were measured with the prototype brachytherapy tube using the dual-ion chamber technique for the 9 Be (d n) 10 B reaction at E d =1.5 MeV. The measurements and simulations agree within uncertainties and demonstrate that fast neutrons contribute more than 90% of the dose to the target volume.

Haijun Song; Jacquelyn C. Yanch; Robert E. Klinkowstein

2002-01-01T23:59:59.000Z

50

Cross Sections for Neutron-induced Reactions on Actinide Targets Extracted from Surrogate Experiments: A Status Report  

SciTech Connect

The Surrogate nuclear reactions method, an indirect approach for determining cross sections for compound-nuclear reactions involving difficult-to-measure targets, is reviewed. Focusing on cross sections for neutron-induced reactions on actinides, we review the successes of past and present applications of the method and assess its uncertainties and limitations. The approximations used in the analyses of most experiments work reasonably well for (n,f) cross sections for neutron energies above 1-2 MeV, but lead to discrepancies for low-energy (n,f) reactions, as well as for (n,{gamma}) applications. Correcting for some of the effects neglected in the approximate analyses leads to improved (n,f) results. We outline steps that will further improve the accuracy and reliability of the Surrogate method and extend its applicability to reactions that cannot be approached with the present implementation of the method.

Escher, J E; Burke, J T; Dietrich, F S; Lesher, S R; Scielzo, N D; Thompson, I J; Younes, W

2009-10-01T23:59:59.000Z

51

Thermal-hydraulic performance of a water-cooled tungsten-rod target for a spallation neutron source  

SciTech Connect

A thermal-hydraulic (T-H) analysis is conducted to determine the feasibility and limitations of a water-cooled tungsten-rod target at powers of 1 MW and above. The target evaluated has a 10-cm x 10-cm cross section perpendicular to the beam axis, which is typical of an experimental spallation neutron source - both for a short-pulse spallation source and long-pulse spallation source. This report describes the T-H model and assumptions that are used to evaluate the target. A 1-MW baseline target is examined, and the results indicate that this target should easily handle the T-H requirements. The possibility of operating at powers >1 MW is also examined. The T-H design is limited by the condition that the coolant does not boil (actual limits are on surface subcooling and wall heat flux); material temperature limits are not approached. Three possible methods of enhancing the target power capability are presented: reducing peak power density, altering pin dimensions, and improving coolant conditions (pressure and temperature). Based on simple calculations, it appears that this target concept should have little trouble reaching the 2-MW range (from a purely T-H standpoint), and possibly much higher powers. However, one must keep in mind that these conclusions are based solely on thermal-hydraulics. It is possible, and perhaps likely, that target performance could be limited by structural issues at higher powers, particularly for a short-pulse spallation source because of thermal shock issues.

Poston, D.I.

1997-08-01T23:59:59.000Z

52

High-power electron beam tests of a liquid-lithium target and characterization study of 7Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy  

Science Journals Connector (OSTI)

Abstract A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the 7Li(p,n)7Be reaction and it will overcome the major problem of removing the thermal power >5 kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4 kW/cm2 and volumetric power density around 2 MW/cm3 at a lithium flow of ~4 m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (?=~2 mm) 1.91 MeV, 3 mA proton beam. A high-intensity proton beam irradiation (1.91–2.5 MeV, 2 mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91 MeV) 7Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors.

S. Halfon; M. Paul; A. Arenshtam; D. Berkovits; D. Cohen; I. Eliyahu; D. Kijel; I. Mardor; I. Silverman

2014-01-01T23:59:59.000Z

53

Design, production, and evaluation of a zircaloy-clad uranium target for an intense pulsed neutron source application  

SciTech Connect

The design of a Zircaloy-2-clad uranium alloy (450 ppm carbon, 250 ppm iron, 350 ppm silicon) target that can function as a pulsed spallation neutron source on interaction of a pulsed 500-MeV proton beam with the uranium nuclei is determined by consideration of irradiation damage, energy deposition, and thermal cycling effects in the target. The designed target is comprised of eight watercooled Zircaloy-2-clad uranium alloy disks, 10 cm in diameter and 2.7 cm thick operating at a maximum uranium alloy centerline temperature of 330/sup 0/C. The production of the Zircaloy-2-clad uranium alloy disks involves remelting of the cast uranium alloy by the consumable electrode technique and bonding of the Zircaloy-2 to the uranium alloy by subjecting the composite to an isostatic-helium pressure at 840/sup 0/C. The lifetime of the disks in the target before cracking of the Zircaloy-2 cladding owing to lowfrequency thermal cycling fatigue is estimated from stress calculations to be about 500 days. The results of thermal cycling tests on a disk tend to confirm the results of the stress calculations.

Loomis, B.A.; Fogle, G.L.; Gerber, S.B.; Thresh, H.R.

1981-12-01T23:59:59.000Z

54

The thick-target {sup 9}Be(d,n) neutron spectra for deuteron energies between 2.6 and 7.0-MeV  

SciTech Connect

The measurement of the zero deg. neutron spectra and yields from deuterons incident on thick beryllium metal targets is described. {sup 235}U and {sup 238}U fission ion chambers were used as neutron detectors to span the neutron energy range above 0.05-MeV with a time resolution of {le} 3 nanosec. Measurements were made for incident deuteron energies from 2.6 to 7.0-MeV, at 0.4-MeV intervals, using time-of-flight techniques with flight paths of 2.7 and 6.8 meters. The results are presented in graphical form and in tables.

Meadows, J.W.

1991-11-01T23:59:59.000Z

55

The thick-target sup 9 Be(d,n) neutron spectra for deuteron energies between 2. 6 and 7. 0-MeV  

SciTech Connect

The measurement of the zero deg. neutron spectra and yields from deuterons incident on thick beryllium metal targets is described. {sup 235}U and {sup 238}U fission ion chambers were used as neutron detectors to span the neutron energy range above 0.05-MeV with a time resolution of {le} 3 nanosec. Measurements were made for incident deuteron energies from 2.6 to 7.0-MeV, at 0.4-MeV intervals, using time-of-flight techniques with flight paths of 2.7 and 6.8 meters. The results are presented in graphical form and in tables.

Meadows, J.W.

1991-11-01T23:59:59.000Z

56

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network (OSTI)

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing scintillation light that is detected using photomultiplier tubes. Statistical limitations of the previous apparatus will be alleviated by significant increases in field strength and trap volume resulting in twenty times more trapped neutrons.

C. M. O'Shaughnessy; R. Golub; K. W. Schelhammer; C. M. Swank; P. -N. Seo; P. R. Huffman; S. N. Dzhosyuk; C. E. H. Mattoni; L. Yang; J. M. Doyle; K. J. Coakley; A. K. Thompson; H. P. Mumm; S. K. Lamoreaux; G. Yang

2009-03-31T23:59:59.000Z

57

Design and Testing of a Prototype Spallation Neutron Source Rotating Target Assembly  

SciTech Connect

The mechanical aspects of an extended vertical shaft rotating target have been evaluated in a full-scale mockup test. A prototype assembly based on a conceptual target design for a 1 to 3-MW spallation facility was built and tested. Key elements of the drive/coupling assembly implemented in the prototype include high integrity dynamic face seals, commercially available bearings, realistic manufacturing tolerances, effective monitoring and controls, and fail-safe shutdown features. A representative target disk suspended on a 3.5 meter prototypical shaft was coupled with the drive to complete the mechanical tests. After1800 hours of operation the test program has confirmed the overall mechanical feasibility of the extended vertical shaft rotating target concept. Precision alignment of the suspended target disk; successful containment of the water and verification of operational stability over the full speed range of 30 to 60 rpm were primary indications the proposed mechanical design is valid for use in a high power target station.

Rennich, Mark J [ORNL; McManamy, Thomas J [ORNL; Graves, Van [Oak Ridge National Laboratory (ORNL); Garmendia, Amaia Zarraoa [IDOM Bilbao; Sorda, Fernando [ESS Bilbao

2010-01-01T23:59:59.000Z

58

Molecular Targeting of the Epidermal Growth Factor Receptor for Neutron Capture Therapy of Gliomas  

Science Journals Connector (OSTI)

...targeting of sufficient amounts of boron-10 to sustain a lethal 10B (n, a...selective uptake of sufficient amounts of boron-10 (109 atoms/cell) by tumor cells...starburst pattern, was boronated with a boron-10 enriched (98% 10B) methylisocyanato...

Rolf. F. Barth; Weilian Yang; Dianne M. Adams; Joan H. Rotaru; Supriya Shukla; Masaru Sekido; Werner Tjarks; Robert A. Fenstermaker; Michael Ciesielski; Marta M. Nawrocky; Jeffrey A. Coderre

2002-06-01T23:59:59.000Z

59

A Measurement of the neutron electric form factor at very large momentum transfer using polaried electrions scattering from a polarized helium-3 target  

SciTech Connect

Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. Of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q{sup 2} and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized {sup 3}He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. G{sup n}{sub E} was measured to be 0.0242 ± 0.0020(stat) ± 0.0061(sys) and 0.0247 ± 0.0029(stat) ± 0.0031(sys) at Q{sup 2} = 1.7 and 2.5 GeV{sup 2}, respectively.

Aidan Kelleher

2010-10-01T23:59:59.000Z

60

A Neutron Generator Utilizing the Deuteron-Deuteron Reaction  

Science Journals Connector (OSTI)

A simple accelerating tube for the production of neutrons by the deuteron-deuteron reaction is described. The neutron intensity from a heavy water ice target is compared with the neutron intensity from a strong Rn—Be source. The yield is found to be 6 mC per microampere of positive ions at 100 kv, and 9 mC per microampere of positive ions at 124 kv. Positive ion currents at the target in excess of one milliampere are obtained. With a beam of deuterons resolved by means of a magnetic field, a constant neutron intensity equivalent to that from a Rn—Be source of 4 curies has been obtained at 100 kv, and 6.5 curies at 124 kv. The neutron yield in the former case is 22 mC per microampere of deuterons and in the latter case is 37 mC per microampere.

Walter H. Zinn and Samuel Seely

1937-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Thermal-hydraulic design of the target/blanket for the accelerator production of tritium conceptual design  

SciTech Connect

A conceptual design was developed for the target/blanket system of an accelerator-based system to produce tritium. The target/blanket system uses clad tungsten rods for a spallation target and clad lead rods as a neutron multiplier in a blanket surrounding the target. The neutrons produce tritium in {sup 3}He, which is contained in aluminum tubes located in the decoupler and blanket regions. This paper presents the thermal-hydraulic design of the target, decoupler, and blanket developed for the conceptual design of the Accelerator Production of Tritium Project, and demonstrates there is adequate margin in the design at full power operation.

Willcutt, G.J.E. Jr.; Kapernick, R.J.

1997-11-01T23:59:59.000Z

62

Correlation between simulations and cavitation-induced erosion damage in Spallation Neutron Source target modules after operation  

SciTech Connect

An explicit finite element (FE) technique developed for estimating dynamic strain in the Spallation Neutron Source (SNS) mercury target module vessel is now providing insight into cavitation damage patterns observed in used targets. The technique uses an empirically developed material model for the mercury that describes liquid-like volumetric stiffness combined with a tensile pressure cut-off limit that approximates cavitation. The longest period each point in the mercury is at the tensile cut-off threshold is denoted its saturation time. Now, the pattern of saturation time can be obtained from these simulations and is being positively correlated with observed damage patterns and is interpreted as a qualitative measure of damage potential. Saturation time has been advocated by collaborators at J-Parc as a factor in predicting bubble nuclei growth and collapse intensity. The larger the ratio of maximum bubble size to nucleus, the greater the bubble collapse intensity to be expected; longer saturation times result in greater ratios. With the recent development of a user subroutine for the FE solver saturation time is now provided over the entire mercury domain. Its pattern agrees with spots of damage seen above and below the beam axis on the SNS inner vessel beam window and elsewhere. The other simulation result being compared to observed damage patterns is mercury velocity at the wall. Related R&D has provided evidence for the damage mitigation that higher wall velocity provides. In comparison to observations in SNS targets, inverse correlation of high velocity to damage is seen. In effect, it is the combination of the patterns of saturation time and low velocity that seems to match actual damage patterns.

Riemer, Bernie [ORNL] [ORNL; McClintock, David A [ORNL] [ORNL; Kaminskas, Saulius [ORNL] [ORNL; Abdou, Ashraf A [ORNL] [ORNL

2014-01-01T23:59:59.000Z

63

ACHIEVING THE REQUIRED COOLANT FLOW DISTRIBUTION FOR THE ACCELERATOR PRODUCTION OF TRITIUM (APT) TUNGSTEN NEUTRON SOURCE  

SciTech Connect

The Accelerator Production of Tritium neutron source consists of clad tungsten targets, which are concentric cylinders with a center rod. These targets are arranged in a matrix of tubes, producing a large number of parallel coolant paths. The coolant flow required to meet thermal-hydraulic design criteria varies with location. This paper describes the work performed to ensure an adequate coolant flow for each target for normal operation and residual heat-removal conditions.

D. SIEBE; K. PASAMEHMETOGLU

2000-11-01T23:59:59.000Z

64

Direction distribution of ambient neutron dose equivalent from 20 MeV protons incident on thick Be and Cu targets  

Science Journals Connector (OSTI)

......takes into account neutrons of energy greater than about...instrument responds down to thermal energy. The deviation of...distribution such as a fission neutron spectrum. Figure 3. The neutron...section from proton-induced reactions on Cu and......

C. Sunil; A. A. Shanbhag; M. Nandy; M. Maiti; T. Bandyopadhyay; P. K. Sarkar

2009-09-01T23:59:59.000Z

65

Role of laser-pulse duration in the neutron yield of deuterium cluster targets K. W. Madison,1  

E-Print Network (OSTI)

laser pulses. We find that the cluster explosion energy and resultant fusion yield are sensitive the achievement of high neutron yield but would provide a cost effective pure DD or DT fusion neutron source [9 study of the ion and fusion neutron yields from explosions of deuterium clusters irradiated with 100-TW

Ditmire, Todd

66

Target  

NLE Websites -- All DOE Office Websites (Extended Search)

Lifetime measurements in Lifetime measurements in inverse kinematics Coulex Target e.g. C Stopper e.g. Cu Beam X X * C Si-Det. Yale Plunger 120 Te at 300 MeV Plunger foils Si-Detector Compton-suppressed Clover detectors (8) 50% Coulomb- barrier )] ( exp[ 1 ) ( 0 d d d P - - - = λ Probability of emitting gamma-ray while in-flight: From data: ) ( ) ( ) ( ) ( ) ( d I d I d P total shifted γ γ = where ) ( ) ( γ γ γ γ θ ε W E N I = Lifetime analysis For example: Valence proton symmetry Data from NNDC, WNSL ( 120 Te), NBI group ( 116 Te), Cologne ( 114 Te) B(E2)up [e 2 b 2 ] N A.A. Pasternak et al., EPJA 13, 435 (2002) O. Möller et al., PRC 71, 064324 (2005) Study deviations from (collective) expectations -> needs a fast and easy way to obtain data -> inverse RDDS well suited! Important in inverse kinematics: Deorientation F I J Large v/c => except for relativistic

67

Systematics of 0-Degrees Neutron-Production by 800 Mev Protons on Targets with 27 Less-Than-Or-Equal-to a Less-Than-Or-Equal-to 238  

E-Print Network (OSTI)

associated cross sections. I. INTRODUCTION We report here absolute measurements of the 0' neutron spectra produced by 800 MeV proton col- lisions with targets of Al, Ti, Cu, W, Pb, and U. The resolution attained in the measurement of the neutron... SYSTEMATICS OF 0 NEUTRON PBODUCTION BY 800 MeV. . . FIG. 1. Plan view of the experimental setup used for the present measurements. The targets were mounted at the location indicated by LD2 in the figure. rotateble target wheel which was used to position...

Bonner, BE; Simmons, J. E.; Newsom, C. R.; Riley, P. J.; Glass, G.; Hiebert, John C.; Jain, M.; Northcliffe, L. C.

1978-01-01T23:59:59.000Z

68

Neutron source, linear-accelerator fuel enricher and regenerator and associated methods  

DOE Patents (OSTI)

A device for producing fissile material inside of fabricated nuclear elements so that they can be used to produce power in nuclear power reactors. Fuel elements, for example, of a LWR are placed in pressure tubes in a vessel surrounding a liquid lead-bismuth flowing columnar target. A linear-accelerator proton beam enters the side of the vessel and impinges on the dispersed liquid lead-bismuth columns and produces neutrons which radiate through the surrounding pressure tube assembly or blanket containing the nuclear fuel elements. These neutrons are absorbed by the natural fertile uranium-238 elements and are transformed to fissile plutonium-239. The fertile fuel is thus enriched in fissile material to a concentration whereby they can be used in power reactors. After use in the power reactors, dispensed depleted fuel elements can be reinserted into the pressure tubes surrounding the target and the nuclear fuel regenerated for further burning in the power reactor.

Steinberg, Meyer (Huntington Station, NY); Powell, James R. (Shoreham, NY); Takahashi, Hiroshi (Setauket, NY); Grand, Pierre (Blue Point, NY); Kouts, Herbert (Brookhaven, NY)

1982-01-01T23:59:59.000Z

69

Proton recoil scintillator neutron rem meter  

DOE Patents (OSTI)

A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

Olsher, Richard H. (Los Alamos, NM); Seagraves, David T. (Los Alamos, NM)

2003-01-01T23:59:59.000Z

70

Multiple tube premixing device  

DOE Patents (OSTI)

The present application provides a premixer for a combustor. The premixer may include a fuel plenum with a number of fuel tubes and a burner tube with a number of air tubes. The fuel tubes extend about the air tubes.

Uhm, Jong Ho; Naidu, Balachandar; Ziminksy, Willy Steve; Kraemer, Gilbert Otto; Yilmaz, Ertan; Lacy, Benjamin; Stevenson, Christian; Felling, David

2013-08-13T23:59:59.000Z

71

Multiple tube premixing device  

DOE Patents (OSTI)

The present application provides a premixer for a combustor. The premixer may include a fuel plenum with a number of fuel tubes and a burner tube with a number of air tubes. The fuel tubes extend about the air tubes.

Uhm, Jong Ho; Varatharajan, Balachandar; Ziminsky, Willy Steve; Kraemer, Gilbert Otto; Yilmaz, Ertan; Lacy, Benjamin; Stevenson, Christian; Felling, David

2012-12-11T23:59:59.000Z

72

Photon doses in NPL standard neutron fields  

Science Journals Connector (OSTI)

......tubes and electronic personal...tubes and electronic personal...manufacturer's handbooks(2, 3...handbook does not give...neutron-photon-electron calculations were made...Scientific. Electronic personal dosemeter handbook, issue 9......

N. J. Roberts; N. A. Horwood; C. J. McKay

2014-10-01T23:59:59.000Z

73

Neutron capture therapy with deep tissue penetration using capillary neutron focusing  

DOE Patents (OSTI)

An improved method for delivering thermal neutrons to a subsurface cancer or tumor which has been first doped with a dopant having a high cross section for neutron capture. The improvement is the use of a guide tube in cooperation with a capillary neutron focusing apparatus, or neutron focusing lens, for directing neutrons to the tumor, and thereby avoiding damage to surrounding tissue.

Peurrung, Anthony J. (Richland, WA)

1997-01-01T23:59:59.000Z

74

Neutron Radiography Facility in a Storage Pond of a Nuclear Power Station Equipped with Antimony-Beryllium Neutron Source  

Science Journals Connector (OSTI)

A neutron radiography facility is described, which has been ... . Some of the control elements contain the neutron absorbing material boron carbide, filled in tubes. Neutron radiography can be applied to detect a...

L. Greim; F. Borchers; M. Greim; G. W. Schumacher; H.-W. Schmitz…

1987-01-01T23:59:59.000Z

75

Downhole pulse tube refrigerators  

SciTech Connect

This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

1997-12-01T23:59:59.000Z

76

Neutronics analysis for an accelerator-based nuclear waste transmuter  

SciTech Connect

The neutronic analysis for a target/blanket design that is capable of supporting the high level waste stream from 2.5 LWR`s is described. The target consists of a set of solid tungsten and lead plates, cooled by heavy water and surrounded by a lead annulus. The annular blanket, which surrounds the target, consists of a set of AcO{sub 2} slurry bearing tubes, each 3 meters long, surrounded by heavy water moderator. Heat removal from the slurry tubes is by passing the rapidly moving slurry through an external heat exchanger. There are separate regions for long-lived fission product burning. Using the Monte Carlo codes LAHET and MCNP we have optimized the design for a minimum beam current of 62.5 mA of 1.6 GeV protons.

Sailor, W.C.; Beard, C.A.

1993-07-01T23:59:59.000Z

77

Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube  

SciTech Connect

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source.

Bucholz, J.A.

2000-07-01T23:59:59.000Z

78

Neutron dose equivalent meter  

DOE Patents (OSTI)

A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

Olsher, Richard H. (Los Alamos, NM); Hsu, Hsiao-Hua (Los Alamos, NM); Casson, William H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM); Kleck, Jeffrey H. (Menlo Park, CA); Beverding, Anthony (Foster City, CA)

1996-01-01T23:59:59.000Z

79

Tube furnace  

DOE Patents (OSTI)

A vermiculite insulated tube furnace is heated by a helically-wound resistance wire positioned within a helical groove on the surface of a ceramic cylinder, that in turn is surroundingly disposed about a doubly slotted stainless steel cylindrical liner. For uniform heating, the pitch of the helix is of shorter length over the two end portions of the ceramic cylinder. The furnace is of large volume, provides uniform temperature, offers an extremely precise programmed heating capability, features very rapid cool-down, and has a modest electrical power requirement.

Foster, Kenneth G. (Livermore, CA); Frohwein, Eugene J. (San Ramon, CA); Taylor, Robert W. (Livermore, CA); Bowen, David W. (Livermore, CA)

1991-01-01T23:59:59.000Z

80

Tapered pulse tube for pulse tube refrigerators  

DOE Patents (OSTI)

Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.

Swift, Gregory W. (Sante Fe, NM); Olson, Jeffrey R. (San Mateo, CA)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Pulsed-neutron monochromator  

DOE Patents (OSTI)

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, H.A. Jr.

1984-01-01T23:59:59.000Z

82

Pulsed-neutron monochromator  

DOE Patents (OSTI)

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, Jr., Herbert A. (Oak Ridge, TN)

1985-01-01T23:59:59.000Z

83

Tube-in-tube thermophotovoltaic generator  

DOE Patents (OSTI)

A thermophotovoltaic device includes at least one thermal radiator tube, a cooling tube concentrically disposed within each thermal radiator tube and an array of thermophotovoltaic cells disposed on the exterior surface of the cooling tube. A shell having a first end and a second end surrounds the thermal radiator tube. Inner and outer tubesheets, each having an aperture corresponding to each cooling tube, are located at each end of the shell. The thermal radiator tube extends within the shell between the inner tubesheets. The cooling tube extends within the shell through the corresponding apertures of the two inner tubesheets to the corresponding apertures of the two outer tubesheets. A plurality of the thermal radiator tubes can be arranged in a staggered or an in-line configuration within the shell.

Ashcroft, John (Scotia, NY); Campbell, Brian (Scotia, NY); DePoy, David (Clifton Park, NY)

1998-01-01T23:59:59.000Z

84

Sequence Design for a Test Tube of Interacting Nucleic Acid Strands  

Science Journals Connector (OSTI)

Sequence Design for a Test Tube of Interacting Nucleic Acid Strands ... We describe an algorithm for designing the equilibrium base-pairing properties of a test tube of interacting nucleic acid strands. ... A target test tube is specified as a set of desired “on-target” complexes, each with a target secondary structure and target concentration, and a set of undesired “off-target” complexes, each with vanishing target concentration. ...

Brian R. Wolfe; Niles A. Pierce

2014-10-20T23:59:59.000Z

85

Neutron-deuteron breakup and quasielastic scattering  

E-Print Network (OSTI)

Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center. The ...

Ohlson, Alice Elisabeth

2009-01-01T23:59:59.000Z

86

Postirradiation evaluations of capsules HANS-1 and HANS-2 irradiated in the HFIR target region in support of fuel development for the advanced neutron source  

SciTech Connect

This report describes the design, fabrication, irradiation, and evaluation of two capsule tests containing U{sub 3}Si{sub 2} fuel particles in contact with aluminum. The tests were in support of fuel qualification for the Advanced Neutron Source (ANS) reactor, a high-powered research reactor that was planned for the Oak Ridge National Laboratory. At the time of these tests, the fuel consisted of U{sub 3}Si{sub 2}, containing highly enriched uranium dispersed in aluminum at a volume fraction of {approximately}0.15. The extremely high thermal flux in the target region of the High Flux Isotope Reactor provided up to 90% burnup in one 23-d cycle. Temperatures up to 450{degrees}C were maintained by gamma heating. Passive SiC temperature monitors were employed. The very small specimen size allowed only microstructural examination of the fuel particles but also allowed many specimens to be tested at a range of temperatures. The determination of fission gas bubble morphology by microstructural examination has been beneficial in developing a fuel performance model that allows prediction of fuel performance under these extreme conditions. The results indicate that performance of the reference fuel would be satisfactory under the ANS conditions. In addition to U{sub 3}Si{sub 2}, particles of U{sub 3}Si, UAl{sub 2}, UAl{sub x}, and U{sub 3}O{sub 8} were tested.

Hofman, G.L.; Snelgrove, J.L. [Argonne National Lab., IL (United States); Copeland, G.L. [Oak Ridge National Lab., TN (United States)

1995-08-01T23:59:59.000Z

87

Neutron capture therapy with deep tissue penetration using capillary neutron focusing  

DOE Patents (OSTI)

An improved method is disclosed for delivering thermal neutrons to a subsurface cancer or tumor which has been first doped with a dopant having a high cross section for neutron capture. The improvement is the use of a guide tube in cooperation with a capillary neutron focusing apparatus, or neutron focusing lens, for directing neutrons to the tumor, and thereby avoiding damage to surrounding tissue. 1 fig.

Peurrung, A.J.

1997-08-19T23:59:59.000Z

88

Advances in 14 MeV neutron activation analysis by means of a new intense neutron source  

Science Journals Connector (OSTI)

A new intense 14 MeV neutron generator with cylindrical acceleration structure has been put in operation at the GKSS Research Center Geesthacht. The sealed neutron tube is combined with...10 n/cm2s. Theoretical s...

R. Pepelnik; H. -U. Fanger; W. Michaelis; B. Anders

1982-01-01T23:59:59.000Z

89

Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA  

E-Print Network (OSTI)

The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400 keV alpha-beam energy and for comparison also using an americium-beryllium neutron source.

M. Anders; D. Trezzi; A. Bellini; M. Aliotta; D. Bemmerer; C. Broggini; A. Caciolli; H. Costantini; P. Corvisiero; T. Davinson; Z. Elekes; M. Erhard; A. Formicola; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyürky; M. Junker; A. Lemut; M. Marta; C. Mazzocchi; R. Menegazzo; P. Prati; C. Rossi Alvarez; D. Scott; E. Somorjai; O. Straniero; T. Szücs

2013-01-30T23:59:59.000Z

90

First neutron generation in the BINP accelerator based neutron source B. Bayanova  

E-Print Network (OSTI)

First neutron generation in the BINP accelerator based neutron source B. Bayanova , A. Burdakova c l e i n f o Keywords: Epithermal neutrons Lithium target Neutron capture therapy Tandem accelerator a b s t r a c t Pilot innovative facility for neutron capture therapy was built at Budker

Taskaev, Sergey Yur'evich

91

Residual Strain Distribution in Bent Composite Boiler Tubes  

SciTech Connect

Kraft recovery boilers are typically constructed of carbon steel boiler tubes clad with a corrosion resistant layer, and these composite tubes are bent and welded together to form air port panels which enable the combustion air to enter the boiler. In this paper, the through-thickness residual strain in the carbon steel layer of non-heat-treated and heat-treated composite bent tubes were measured by neutron diffraction techniques and modeled by finite element modeling. The results can be used to optimize material selection and manufacturing processes to prevent stress corrosion and corrosion fatigue cracking in the boiler tubes.

Hubbard, Camden R [ORNL; Gorti, Sarma B [ORNL; Tang, Fei [ORNL

2006-01-01T23:59:59.000Z

92

Fracture analysis of HFIR beam tube caused by radiation embrittlement  

SciTech Connect

With an attempt to estimate the neutron beam tube embrittlement condition for the Oak Ridge High Flux Isotope Reactor (HFIR), fracture mechanics calculations are carried out in this paper. The analysis provides some numerical result on how the tube has been structurally weakened. In this calculation, a lateral impact force is assumed. Numerical result is obtained on how much the critical crack size should be reduced if the beam tube has been subjected to an extended period of irradiation. It is also calculated that buckling strength of the tube is increased, not decreased, with irradiation.

Chang, S.J. [Oak Ridge National Lab., TN (United States). Research Reactors Div.

1994-12-31T23:59:59.000Z

93

Microhole Tubing Bending Report  

DOE Data Explorer (OSTI)

A downhole tubing bending study was made and is reported herein. IT contains a report and 2 excel spreadsheets to calculate tubing bending and to estimate contact points of the tubing to the drilled hole wall (creating a new support point).

Oglesby, Ken

94

Helium-filled aluminum flight tubes  

NLE Websites -- All DOE Office Websites (Extended Search)

Helium-filled aluminum flight tubes. Helium-filled aluminum flight tubes. Detector housing for the CCD camera lens, mirror, and scintillator. For more information, contact Instrument Scientist: Hassina Bilheux, bilheuxhn@ornl.gov, 865.384.9630 neutrons.ornl.gov/instruments/HFIR/factsheets/Instrument-cg1d.pdf The CG-1D beam is used for neutron imaging measurements using a white beam. Apertures (with different diameters D (pinhole geometry) are used at the entrance of the helium-filled flight path to allow L/D variation from 400 to 800. L is the distance between the aperture and the detector (where the image is produced). Samples sit on a translation/ rotation stage for alignment and tomography purposes. Detectors for CG-1D include

95

Gated SIT vidicon streak tube  

SciTech Connect

A recently developed prototype streak tube designed to produce high gain and resolution by incorporating the streak and readout functions in one envelope thereby minimizing photon-to-change transformations and eliminating external coupling losses is presented. The tube is based upon a grid-gated Silicon-Intensified-Target Vidicon (SITV) with integral Focus Projection Scan (FPS) TV readout. Demagnifying electron optics (m=0.63) in the image section map the 40-mm-diameter photocathode image unto a 25-mm-diameter silicon target where gains greater than or equal to10/sup 3/ are achieved with only 10 KV accelerating voltage. This is compared with much lower gains (approx.50) at much higher voltages (approx.30 KV) reported for streak tubes using phosphor screens. Because SIT technology is well established means for electron imaging in vacuum, such fundamental problems as ''backside thinning'' required for electron imaging unto CCDs do not exist. The high spatial resolution (approx.30 lp/mm), variable scan formats, and high speed electrostatic deflection (250 mm/sup 2/ areas are routinely rastered with 256 scan lines in 1.6 ms) available from FPS readout add versatility not available in CCD devices. Theoretical gain and spatial resolution for this design (developed jointly by Los Alamos National Laboratory and General Electric Co.) are compared with similar calculations and measured data obtained for RCA 73435 streaks fiber optically coupled to (1) 25-mm-diameter SIT FPS vidicons and (2) 40-mm-diameter MCPTs (proximity-focused microchannel plate image intensifier tubes) fiber optically coupled to 18-mm-diameter Sb/sub 2/S/sub 3/ FPS vidicons. Sweep sensitivity, shutter ratio, and record lengths for nanosecond duration (20 to 200 ns) streak applications are discussed.

Dunbar, D.L.; Yates, G.J.; Black, J.P.

1985-01-01T23:59:59.000Z

96

Neutron reflectometry  

Science Journals Connector (OSTI)

Neutron reflectivity is a powerful tool for the ... chapter include: the theory of elastic specular neutron diffraction; polarized neutron reflectivity; surface roughness; experimental methodology; resolution in ...

G. S. Smith; C. F. Majkrzak

2004-01-01T23:59:59.000Z

97

Boron Neutron Capture Therapy for Murine Malignant Gliomas  

Science Journals Connector (OSTI)

...September 1992 research-article Boron Neutron Capture Therapy for Murine Malignant Gliomas...Washington Street, Boston, MA 02111. Boron neutron capture therapy (BNCT) involves administration of a boron compound followed by neutron irradiation of the target organ. The...

Stephen C. Saris; Guido R. Solares; David E. Wazer; Guillermo Cano; Sarah E. Kerley; Melita A. Joyce; Lester S. Adelman; Otto K. Harling; Hywel Madoc-Jones; Robert G. Zamenhof

1992-09-01T23:59:59.000Z

98

Biaxial creep behavior of textured zircaloy tubing  

SciTech Connect

This paper reports on zirconium alloys which are commonly used in light-water reactors as thin-walled tubing to clad highly radioactive fuel. The tubes experience varied stresses at high temperatures while being exposed to high-neutron radiation, resulting in thermal creep and radiation growth and creep. However, the dimensional stability of these materials is important to preventing leakage of fission gases and contamination of the coolant water. Predicting the dimensional changes of the thin-walled tubes is further complicated by the anisotropic nature of the hexagonal close-packaged metals. This article summarizes the procedures used in the texture analyses and crystal plasticity in developing model equations to predict the dimensional changes of Zircaloy fuel cladding, both out-of-pile and in-reactor. These methodologies can be extended to the life prediction of these important structures in nuclear reactors.

Murty, L.K. (North Carolina State Univ., NC (US))

1992-02-01T23:59:59.000Z

99

Shifting scintillator neutron detector  

DOE Patents (OSTI)

Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

Clonts, Lloyd G; Cooper, Ronald G; Crow, Jr., Morris Lowell; Hannah, Bruce W; Hodges, Jason P; Richards, John D; Riedel, Richard A

2014-03-04T23:59:59.000Z

100

Neutron-Neutron Interaction  

Science Journals Connector (OSTI)

The present status of the problem of charge dependence is discussed. The information about the neutron-neutron interaction derived from the two-neutron system, three-nucleon systems, final-state interactions in multiparticle reactions, and peripheral processes is critically evaluated. The experimental data indicate the breakdown of charge independence by about 3-5%. Evidence concerning the violation of charge symmetry is inconclusive, but it seems that most of the data are consistent with the assumption that charge symmetry is satisfied within 0.5-1%. The most suitable studies which might improve the knowledge of the neutron-neutron forces are indicated.

IVO ŠLAUS

1967-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Neutron-deuteron breakup reaction as a tool for studying neutron-neutron interactions  

SciTech Connect

An analysis of the most recent data on the reaction nd {yields} pnn revealed a serious discrepancy between theoretical predictions and cross sections measured for this reaction in various configurations where the role of neutron-neutron interactions is important. In view of this, it seems necessary both to develop theoretical approaches and to obtain new experimental data. For this purpose, a setup for studying the neutron-deuteron breakup reaction was created at the Institute for Nuclear Research on the basis of the neutron beam in the RADEX channel and deuterium targets. This facility makes it possible to perform experiments over a broad region of primary-neutron energies (10-60 MeV) and in various (final-state interaction, quasifree scattering, and spatial-star) configurations. Preliminary results of the respective experiment were obtained for configurations of final-state neutron-neutron interaction and quasifree neutron-neutron scattering.

Konobeevski, E. S., E-mail: konobeev@inr.ru; Zuyev, S. V.; Mordovskoy, M. V.; Potashev, S. I.; Sharapov, I. M. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)] [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2013-11-15T23:59:59.000Z

102

Conduction cooled tube supports  

DOE Patents (OSTI)

In boilers, process tubes are suspended by means of support studs that are in thermal contact with and attached to the metal roof casing of the boiler and the upper bend portions of the process tubes. The support studs are sufficiently short that when the boiler is in use, the support studs are cooled by conduction of heat to the process tubes and the roof casing thereby maintaining the temperature of the stud so that it does not exceed 1400.degree. F.

Worley, Arthur C. (Mt. Tabor, NJ); Becht, IV, Charles (Morristown, NJ)

1984-01-01T23:59:59.000Z

103

Wound tube heat exchanger  

DOE Patents (OSTI)

What is disclosed is a wound tube heat exchanger in which a plurality of tubes having flattened areas are held contiguous adjacent flattened areas of tubes by a plurality of windings to give a double walled heat exchanger. The plurality of windings serve as a plurality of effective force vectors holding the conduits contiguous heat conducting walls of another conduit and result in highly efficient heat transfer. The resulting heat exchange bundle is economical and can be coiled into the desired shape. Also disclosed are specific embodiments such as the one in which the tubes are expanded against their windings after being coiled to insure highly efficient heat transfer.

Ecker, Amir L. (Duncanville, TX)

1983-01-01T23:59:59.000Z

104

Coiled Tubing Safety Manual  

SciTech Connect

This document addresses safety concerns regarding the use of coiled tubing as it pertains to the preservation of personnel, environment and the wellbore.

Crow, W.

1999-04-06T23:59:59.000Z

105

Spallation-Driven Cold Neutron Sources Dr. Bradley J. Micklich  

E-Print Network (OSTI)

Neutrons were produced by spallation/fission by 450MeV protons striking depleted uranium target Proton

McDonald, Kirk

106

SCIENCE HIGHLIGHTS 2008 ANNUAL REPORT ORNL NEUTRON SCIENCES neutrons.ornl.gov  

E-Print Network (OSTI)

diseased areas of the body. Targeted Drug Delivery Systems A young researcher in the Neutron Scattering SciSCIENCE HIGHLIGHTS 2008 ANNUAL REPORT ORNL NEUTRON SCIENCES neutrons.ornl.gov 14 Studies when it is introduced into the body. So we developed a synergistic approach, combining various neutron

107

Target design optimization for an electron accelerator driven subcritical facility with circular and square beam profiles.  

SciTech Connect

A subcritical facility driven by an electron accelerator is planned at the Kharkov Institute of Physics and Technology (KIPT) in Ukraine for medical isotope production, materials research, training, and education. The conceptual design of the facility is being pursued through collaborations between ANL and KIPT. As part of the design effort, the high-fidelity analyses of various target options are performed with formulations to reflect the realistic configuration and the three dimensional geometry of each design. This report summarizes the results of target design optimization studies for electron beams with two different beam profiles. The target design optimization is performed via the sequential neutronic, thermal-hydraulic, and structural analyses for a comprehensive assessment of each configuration. First, a target CAD model is developed with proper emphasis on manufacturability to provide a basis for separate but consistent models for subsequent neutronic, thermal-hydraulic, and structural analyses. The optimizations are pursued for maximizing the neutron yield, streamlining the flow field to avoid hotspots, and minimizing the thermal stresses to increase the durability. In addition to general geometric modifications, the inlet/outlet channel configurations, target plate partitioning schemes, flow manipulations and rates, electron beam diameter/width options, and cladding material choices are included in the design optimizations. The electron beam interactions with the target assembly and the neutronic response of the subcritical facility are evaluated using the MCNPX code. the results for the electron beam energy deposition, neutron generation, and utilization in the subcritical pile are then used to characterize the axisymmetric heat generation profiles in the target assembly with explicit simulations of the beam tube, the coolant, the clad, and the target materials. Both tungsten and uranium are considered as target materials. Neutron spectra from tungsten and uranium are very similar allowing the use of either material in the subcritical assembly without changing its characteristics. However, the uranium target has a higher neutron yield, which increases the neutron flux of the subcritical assembly. Based on the considered dimensions and heat generation profiles, the commercial CFD software Star-CD is used for the thermal-hydraulic analysis of each target design to satisfy a set of thermal criteria, the most limiting of which being to maintain the water temperature 50 below the boiling point. It is found that the turbulence in the inlet channels dissipates quickly in narrow gaps between the target plates and, as a result, the heat transfer is limited by the laminar flow conditions. On average, 3-D CFD analyses of target assemblies agree well with 1-D calculations using RELAP (performed by KIPT). However, the recirculation and stagnation zones predicted with the CFD models prove the importance of a 3-D analysis to avoid the resulting hotspots. The calculated temperatures are subsequently used for the structural analysis of each target configuration to satisfy the other engineering design requirements. The thermo-structural calculations are performed mostly with NASTRAN and the results occasionally compared with the results from MARC. Both, NASTRAN and MARC are commercially available structural-mechanics analysis software. Although, a significant thermal gradient forms in target elements along the beam direction, the high thermal stresses are generally observed peripherally around the edge of thin target disks/plates. Due to its high thermal conductivity, temperatures and thermal stresses in tungsten target are estimated to be significantly lower than in uranium target. The deformations of the target disks/plates are found to be insignificant, which eliminate concerns for flow blockages in narrow coolant channels. Consistent with the specifications of the KIPT accelerator to be used in this facility, the electron beam power is 100-kW with electron energy in the range of 100 to 200 MeV. As expected, the 100 MeV el

Gohar, M. Y. A; Sofu, T.; Zhong, Z.; Belch, H.; Naberezhnev, D.; Nuclear Engineering Division

2008-10-30T23:59:59.000Z

108

Analysis of composite tube cracking in recovery boiler floors  

SciTech Connect

Cracking of co-extruded (generally identified as composite) floor tubes in kraft black liquor recovery boilers was first observed in Scandinavia, but this problem has now been found in many North American boilers. In most cases, cracking in the outer 304L stainless steel has not progressed into the carbon steel, but the potential for such crack propagation is a cause of concern. A multidimensional study has been initiated to characterize the cracking seen in composite floor tubes, to measure the residual stresses resulting from composite tube fabrication, and to predict the stresses in tubes under operating conditions. The characterization studies include review of available reports and documents on composite tube cracking, metallographic examination of a substantial number of cracked tubes, and evaluation of the dislocation structure in cracked tubes. Neutron and X-ray diffraction are being used to determine the residual stresses in composite tubes from two major manufacturers, and finite element analysis is being used to predict the stresses in the tubes during normal operation and under conditions where thermal fluctuations occur.

Keiser, J.R.; Taljat, B.; Wang, X.L.; Maziasz, P.J.; Hubbard, C.R.; Swindeman, R.W. [Oak Ridge National Lab., TN (United States); Singbeil, D.L.; Prescott, R. [Pulp and Paper Research Inst. of Canada, Vancouver, British Columbia (Canada)

1996-08-01T23:59:59.000Z

109

Neutron-deuteron breakup and quasielastic scattering .  

E-Print Network (OSTI)

??Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons… (more)

Ohlson, Alice Elisabeth

2009-01-01T23:59:59.000Z

110

THERMAL NEUTRON BACKSCATTER IMAGING.  

SciTech Connect

Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

2004-10-16T23:59:59.000Z

111

Characteristics of a RF-Driven Ion Source for a Neutron Generator Used for Associated Particle Imaging  

SciTech Connect

We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium ({sup 2}D({sup 3}T,n){sup 4}{alpha}) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 10{sup 8} n/s for a 50 {mu}A D/T ion beam current accelerated to 80 kV. The generator utilizes an RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80% can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results from ion source testing, such as the current density, atomic ion fraction, electron temperature, and electron density will be discussed.

Wu Ying; Leung, K.-N. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Nuclear Engineering, University of California-Berkeley, Berkeley, CA 94720 (United States); Hurley, John P. [Special Technologies Laboratory, Santa Barbara, CA 93111 (United States); Ji Qing; Kwan, Joe [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

2009-03-10T23:59:59.000Z

112

Ris-M-2208 MECHANICAL VELOCITY SELECTOR, NEUTRON FLUX AND Q-RANGE  

E-Print Network (OSTI)

the geometry of the proposed small angle neutron scattering (SANS) instrument. At the end of the tube, corre APPENDIX B 23 APPENDIX C 26 #12;- 5 - I. INTRODUCTION The proposed Small Angle Neutron Scattering (SANSRisø-M-2208 MECHANICAL VELOCITY SELECTOR, NEUTRON FLUX AND Q-RANGE FOR THE SMALL ANGLE NEUTRON

113

Boiler Stack Economizer Tube Failure  

Science Journals Connector (OSTI)

A metallurgical evaluation was performed to investigate the failure of a type 304 stainless steel tube from a boiler stack economizer. The tube had three distinct degradation mechanisms...

Ryan J. Haase; Larry D. Hanke

2013-10-01T23:59:59.000Z

114

First neutron generation in the BINP accelerator based neutron source  

Science Journals Connector (OSTI)

Pilot innovative facility for neutron capture therapy was built at Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using 7Li(p,n)7Be threshold reaction. The results of the first experiments on neutron generation are reported and discussed.

B. Bayanov; A. Burdakov; V. Chudaev; A. Ivanov; S. Konstantinov; A. Kuznetsov; A. Makarov; G. Malyshkin; K. Mekler; I. Sorokin; Yu. Sulyaev; S. Taskaev

2009-01-01T23:59:59.000Z

115

How the Spallation Neutron Source Works | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

high-energy proton pulses strike a heavy-metal target, which is a container of liquid mercury. Corresponding pulses of neutrons freed by the spallation process are slowed down in...

116

Neutron Polarimetry  

Science Journals Connector (OSTI)

8 July 1993 research-article Neutron Polarimetry P. Jane Brown J. Bruce Forsyth Francis Tasset Zero-field neutron polarimetry is a technique which has...polarization analysis to be carried out in a neutron scattering experiment. The incident...

1993-01-01T23:59:59.000Z

117

Protons hog the momentum in neutron-rich nuclei | Argonne National...  

NLE Websites -- All DOE Office Websites (Extended Search)

a greater fraction of the protons than neutrons to have high momentum in relatively neutron-rich nuclei. The CLAS detector completely surrounds an experimental target and is...

118

E-Print Network 3.0 - advanced pulsed-neutron research Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fuels ; Geosciences 13 Major Facilities for Materials Research Summary: Neutron Source: upgrading of the National Magnet Laboratory: and enriched pulsed neutron targets... and...

119

Photomultiplier Tube Testing  

NLE Websites -- All DOE Office Websites (Extended Search)

Photomultiplier Tube Testing for the MiniBooNE Experiment B. T. Fleming, L. Bugel, E. Hawker, S. Koutsoliotas, S. McKenney, V. Sandberg, and D. Smith for the MiniBooNE...

120

Flameless tube sealing apparatus  

SciTech Connect

A flameless sealer for glass and polymeric tubes uses a circular filament as a heating element and can be used for sealing relatively large diameter tubes while they are within a glovebox or other protected enclosure. The electrically conductive rods extending from a non-conductive base which defines an aperture for mounting the apparatus to a lattice rod of a glove box. A remotely located power supply provides electrical power to the filament. 2 figs.

McFarlan, J.T.; Zwick, B.D.; Avens, L.R.

1991-03-04T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Neutron capture therapies  

DOE Patents (OSTI)

In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

1999-01-01T23:59:59.000Z

122

Texture control of zircaloy tubing during tube reduction  

SciTech Connect

Seven batches of Zircaloy-2 nuclear fuel cladding tubes with different textures were processed from tube shells of the same size, by different reduction routes, using pilger and 3-roll mills. Based on the texture data of these tubes, the texture control of Zircaloy tubing, the texture gradient across the wall, and the texture change during annealing were studied. The deformation texture of Zicaloy-2 tubing was dependent on the tool's curvature and was independent of the dimensions of the mother tubes. The different slopes of texture gradients were observed between the tubing of higher strain ration and that of lower strain ratio.

Nagai, N.; Kakuma, T.; Fujita, K.

1982-01-01T23:59:59.000Z

123

A neutron transmission study of environmental Gd  

E-Print Network (OSTI)

A new method for the determination of environmental Gd by neutron transmission (NT) experiments is proposed. The NT method is based on the measurements of neutron spectra passing through a target. From the attenuation neutron spectra new data as concentration, width, resonance energies and cross section have been obtained.

Cristiana Oprea; Ioan Alexandru Oprea; Alexandru Mihul

2014-06-02T23:59:59.000Z

124

Neutron Production, Neutron Facilities and Neutron Instrumentation  

Science Journals Connector (OSTI)

...Mexico, 87545, U.S.A, e-mail: sven@lanl.gov Hans-Georg Priesmeyer Geesthacht Neutron Scattering Facility, GKSS Research Center, 21502 Geesthacht, Germany, e-mail: hans-georg.priesmeyer@gkss.de NEUTRON GENERATION The...

Sven C. Vogel; Hans-Georg Priesmeyer

125

Neutron Reflectivity  

Science Journals Connector (OSTI)

Neutron Reflectivity ... This article is part of the Neutron Reflectivity special issue. ... The articles in this special issue on neutron reflectivity cover a broad range of the applications of this technique and the related X-ray and neutron scattering experiments of SAXS, SANS, GISAXS, and GISANS. ...

Jeffrey Penfold

2009-03-31T23:59:59.000Z

126

About Neutrons  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Basics Neutron Basics A neutron is one of the fundamental particles that make up matter. This uncharged particle exists in the nucleus of a typical atom, along with its positively charged counterpart, the proton. Protons and neutrons each have about the same mass, and both can exist as free particles away from the nucleus. In the universe, neutrons are abundant, making up more than half of all visible matter. Find Out What a Neutron Is Youtube icon Properties of Neutrons How Can Neutrons Be Used for Research? Image of glucose movement in plants Neutron imaging techniques have been able to determine the precise movement of glucose in plants. This knowledge can help scientists better understand how biomass can be efficiently converted into fuel. Neutrons have many properties that make them ideal for certain types of

127

Proton-Neutron Scattering  

Science Journals Connector (OSTI)

Using Glauber multiple-scattering theory, the missing-mass spectrum for protons scattered off a deuterium target is computed. The relatively clean separation of the single- and double-scattering peaks offers the possibility of determining the high-energy proton-neutron differential cross section.

N. Straumann and C. Wilkin

1970-03-02T23:59:59.000Z

128

Accelerator driven production of tritium: target and blanket design  

E-Print Network (OSTI)

of neutrons in the 'target' and the use of these neutrons in the 'blanket assembly'. The systems described in this thesis employ a linear accelerator (1 GeV protons, I 00 mA beam current), lead targets for the production of neutrons via spallation reactions...

Ragusa, Jean Concetto

2012-06-07T23:59:59.000Z

129

POWDER: The Neutron Powder Diffractometer at HFIR | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Powder Diffractometer Neutron Powder Diffractometer Neutron Powder Diffractometer. Neutron Powder Diffractometer. The HB-2A diffractometer is a workhorse instrument used to conduct crystal structural and magnetic structural studies of powdered and ceramic samples, particularly as a function of intensive conditions (T, P, H, etc.). Powder diffraction data collected on this instrument are ideally suited for the Rietveld method. A full range of ancillary sample environments can be used, including cryofurnaces (4-800 K), furnaces (to 1800 K), cryostats (to 0.3 K), and cryomagnets (to 7 T). The Powder Diffractometer has a Debye-Scherrer geometry. The detector bank has 44 3He tubes, each with 6' Soller collimators. A germanium wafer-stack monochromator is vertically focusing and provides one of three principal

130

Analysis of cracking of co-extruded recovery boiler floor tubes  

SciTech Connect

Cracking of the stainless steel layer in co-extruded 304L/SA210 tubing used in black liquor recovery boilers is being found in an ever-increasing number of North American pulp and paper mills. Because of the possibility of a tube failure, this is a significant safety issue, and, because of the extra time required for tube inspection and repair, this can become an economic issue as well. In a project funded by the U.S. Department of Energy and given wide support among paper companies, boiler manufacturers, and tube fabricators, studies are being conducted to determine the cause of the cracking and to identify alternate materials and/or operating procedures to prevent tube cracking. Examination of cracked tubes has permitted characterization of crack features, and transmission electron microscopy is providing information about the thermal history, particularly cyclic thermal exposures, that tubes have experienced. Neutron and x-ray diffraction techniques are being used to determine the residual stresses in as-fabricated tube panels and exposed tubes, and finite element modeling is providing information about the stresses the tubes experience during operation. Laboratory studies are being conducted to determine the susceptibility of the co-extruded 304L/SA210 tubes to stress corrosion cracking, thermal fatigue, and corrosion in molten smelt. This paper presents the current status of these studies. On the basis of all of these studies, recommendations for means to prevent tube cracking will be offered.

Keiser, J.R.; Taljat, B.; Wang, X.L. [and others

1997-08-01T23:59:59.000Z

131

Elastic neutron scattering studies at 96 MeV for transmutation  

Science Journals Connector (OSTI)

......POSTER Presentations Elastic neutron scattering studies at 96 MeV for transmutation...University, Japan Elastic neutron scattering from 12C, 14N, 16O, 28Si...a nuclear target. Elastic neutron scattering is of utmost importance for......

M. Österlund; J. Blomgren; M. Hayashi; P. Mermod; L. Nilsson; S. Pomp; A. Öhrn; A. V. Prokofiev; U. Tippawan

2007-08-01T23:59:59.000Z

132

Current Status and Future Works of Neutron Scattering Laboratory at BATAN in Serpong  

SciTech Connect

Current status of neutron beam instruments using neutrons produced by the Multi Purpose Research Reactor--30MWth (MPR 30, RSG GA Siwabessy) located in Serpong is presented. Description of the reactor as the neutron source is mentioned briefly. There are six neutron beam tubes coming from the beryllium reflector surrounding half of the reactor core providing neutrons in the experimental hall of the reactor (XHR). Four of them are dedicated to R and D in materials science using neutron scattering techniques. Neutron Radiography Facility (NRF), Triple Axis Spectrometer (TAS) and Residual Stress Measurement (RSM) Diffractometer are installed respectively at beam tubes S2, S4 and S6. The largest neutron beam tube (S5) is exploited to accommodate two neutron guide tubes that transfer the neutrons to a neighbouring building called neutron guide hall (NGH). There are three other neutron beam instruments installed in this building, namely Small Angle Neutron Scattering (SANS) Spectrometer (SMARTer), High Resolution SANS (HRSANS) Spectrometer and High Resolution Powder Diffractometer (HRPD). In the XHR, a Four Circle and Texture Diffractometer (FCD/TD) is attached to one of the neutron guide tubes. These seven instruments were installed to utilize the neutrons for materials science research, and recently the RSM diffractometer has shown its capabilities in identifying different amount of stress left due to different treatments of welding in fuel cladding, while the SANS spectrometer is now gaining capabilities in identifying different sizes and shapes of macromolecules in polymers as well as investigations of magnetic samples. In the mean time, non-destructive tests using the NRF is gathering more confidence from some latest real time measurements eventhough there are still some shortcomings in the components and their alignments. Future works including improvement of each facility and its components, even replacement of some parts are necessary and have to be carried out carefully. A plan for developing a neutron reflectometer at one of the neutron guide in the Neutron Guide Hall is also part of the near future activities.

Ikram, A. [Center of Technology for Nuclear Industrial Materials, National Nuclear Energy Agency of Indonesia (BATAN) Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia)

2008-03-17T23:59:59.000Z

133

Fluorescent Tube Lamps  

Energy.gov (U.S. Department of Energy (DOE))

FEMP temporarily suspended its energy efficiency requirements for fluorescent tube lamps as it evaluates the market impact of the pending 2012 minimum efficiency standards for fluorescent lamps. The program will issue updated energy efficiency requirements when the market distribution of this product category stabilizes and when doing so has the potential to result in significant Federal energy savings.

134

Artificial Production of Neutrons  

Science Journals Connector (OSTI)

A porcelain vacuum tube capable of producing currents of positive ions up to 30 microamperes and with energies up to 106 electron-volts has been constructed and used for artificial disintegration experiments. Neutrons have been produced by bombarding beryllium with helium ions, and by bombarding lithium and beryllium with the ions of the heavy isotope of hydrogen. The curve obtained for the efficiency of production of neutrons by helium ions as a function of voltage is in agreement with the curve obtained by a downward extrapolation of curves known from work with polonium ?-particles. The present paper is mainly a discussion of the apparatus and methods of measurement, since brief reports of the results have already been presented.

H. R. Crane; C. C. Lauritsen; A. Soltan

1934-04-15T23:59:59.000Z

135

Neutron-Neutron Scattering Length  

Science Journals Connector (OSTI)

The final-state interaction of the two neutrons from the reaction ?-+d?2n+? has a pronounced and distinctive effect on the momentum spectrum of the outgoing particles. In particular, the neutron spectrum is sharply peaked in the neighborhood of 2 Mev, with a shape that is quite sensitive to the strength of the nn interaction. In the region of this peak, the relative neutron-neutron momentum is so small that the nn interaction is completely characterized by its scattering length. Hence it is proposed that a measurement of the shape of the neutron spectrum from this reaction may provide a convenient means of measuring the neutron-neutron scattering length. Neutron spectra are calculated in an impulse approximation, for several assumed values of the scattering length. It appears from their shapes that, in this way, present neutron-detection techniques should be capable of determining the scattering length to within 25%.

Kirk W. McVoy

1961-03-01T23:59:59.000Z

136

Neutron skins and neutron stars  

SciTech Connect

The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ('PREX') at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in {sup 208}Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron beams may impact the physics of neutron stars.

Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

2013-11-07T23:59:59.000Z

137

Advanced Neutron Source (ANS) Project progress report  

SciTech Connect

This report discusses the following topics on the advanced neutron source: quality assurance (QA) program; reactor core development; fuel element specification; corrosion loop tests and analyses; thermal-hydraulic loop tests; reactor control concepts; critical and subcritical experiments; material data, structural tests, and analysis; cold source development; beam tube, guide, and instrument development; hot source development; neutron transport and shielding; I C research and development; facility concepts; design; and safety.

McBee, M.R.; Chance, C.M. (eds.) (Oak Ridge National Lab., TN (USA)); Selby, D.L.; Harrington, R.M.; Peretz, F.J. (Oak Ridge National Lab., TN (USA))

1990-04-01T23:59:59.000Z

138

Neutron scattering  

Science Journals Connector (OSTI)

... likely to be able to contribute to many different branches of chemistry and secondly because neutron ...neutronscattering ...

A. J. Leadbetter

1977-12-01T23:59:59.000Z

139

Photomultiplier Tube Home  

NLE Websites -- All DOE Office Websites (Extended Search)

Project Homepage Project Homepage Classroom Projects Homepage - Teacher Homepage - Student Homepage Abstract: Photons are created in scintillator devices in most modern particle detectors. These photons yield information about particle collisions that must be measured and decoded. This Website follows the track of a photon as it enters a photomultiplier tube (pmt), an amplifying device that increases the effect of a single photon to levels that are measurable. This signal amplification is crucial; without it, no information exists for decoding. The site presents information regarding the innards of a pmt and allows students to investigate predictive mathematical models describing the signal increase under different, adjustable parameters. Introduction to Research: Photomultipler tubes are omnipresent in particle physics. Understanding the

140

Neutron Diffraction  

Science Journals Connector (OSTI)

22 February 1949 research-article Neutron Diffraction G. E. Bacon J. Thewlis The problem of neutron diffraction by crystals is treated by analogy...deals with a comparison between X-ray and neutron diffraction and it is shown that quantitatively...

1949-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Joined concentric tubes  

DOE Patents (OSTI)

Tubular objects having two or more concentric layers that have different properties are joined to one another during their manufacture primarily by compressive and friction forces generated by shrinkage during sintering and possibly mechanical interlocking. It is not necessary for the concentric tubes to display adhesive-, chemical- or sinter-bonding to each other in order to achieve a strong bond. This facilitates joining of dissimilar materials, such as ceramics and metals.

DeJonghe, Lutgard; Jacobson, Craig; Tucker, Michael; Visco, Steven

2013-01-01T23:59:59.000Z

142

High efficiency proportional neutron detector with solid liner internal structures  

DOE Patents (OSTI)

A tube-style neutron detector, a panel-style neutron detector incorporating a plurality of tube-style neutron detectors, and a panel-style neutron detector including a plurality of anode wires are provided. A plurality of channels is provided in a neutron detector such that each channel has an inner surface of a coating layer including a neutron-absorbing material. A wire anode is provided at end of each channel so that electrons generated by a charged daughter particle generated by a neutron are collected to detect a neutron-matter interaction. Moderator units can be incorporated into a neutron detector to provide improved detection efficiencies and/or to determine neutron energy spectrum. Gas-based proportional response from the neutron detectors can be employed for special nuclear material (SNM) detection. This neutron detector can provide similar performance to .sup.3He-based detectors without requiring .sup.3He and without containing toxic, flammable, or high-pressure materials.

Kisner, Roger Allen; Holcomb, David Eugene; Brown, Gilbert M.

2014-08-05T23:59:59.000Z

143

Inspecting the minefield and residual explosives by fast neutron activation method  

SciTech Connect

As an upgrade of a robotic mobile system for antipersonnel land-mine clearance, a fast neutron probe has been considered for the detection of mines and explosive residues. Laboratory tests were made by using the 14 MeV 6 x 10{sup 7} neutrons/sec beam with the associated alpha particle detection and with a LaBr{sub 3} gamma ray detector. Simulant of the anti-personal mine was used as a target. Several measurements were made with the target buried into the soil at different depths. For each depth minimal time measurement was estimated for false negative 0.4 % and false positive equal to 10 %. Tests showed that is possible to detect buried land-mine as well as residual explosives; however, in order to reach the optimal speed of 10 cm/s for de-mining vehicle it is necessarily to use several sealed tube neutron generators and few tens of LaBr{sub 3} gamma ray detectors. (authors)

Sudac, D. [Rudjer Boskovic Inst., Bijenicka c. 54, 10000 Zagreb (Croatia); Majetic, S. [DOK-ING Ltd., Kanalski put 1, 10000 Zagreb (Croatia); Kollar, R. [A.C.T. D.o.o., Prilesje 4, 10000 Zagreb (Croatia); Nad, K.; Obhodas, J. [Rudjer Boskovic Inst., Bijenicka c. 54, 10000 Zagreb (Croatia); Valkovic, V. [A.C.T. D.o.o., Prilesje 4, 10000 Zagreb (Croatia)

2011-07-01T23:59:59.000Z

144

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Former User Group Chair Enthusiastic About Relevance of Neutron Scattering Former User Group Chair Enthusiastic About Relevance of Neutron Scattering to Industrial Research Former User Group Chair Mike Crawford Mike Crawford, DuPont Research and Development. The drive is intensifying to encourage research partnerships between Neutron Sciences and private industry. Such partnerships, a long-term strategic goal set by the DOE's Basic Energy Sciences Advisory Committee, will deliver industry and its technological problems to SNS and HFIR, where joint laboratory-industry teams can use the unparalleled resources available here to resolve them. "SNS is a tremendous facility. It has the potential to have a couple of thousand user visits a year and, if they build another target station in the future, you're probably talking about 4000 user visits a year,"

145

Ultrafast neutron detector  

DOE Patents (OSTI)

The invention comprises a neutron detector (50) of very high temporal resolution that is particularly well suited for measuring the fusion reaction neutrons produced by laser-driven inertial confinement fusion targets. The detector comprises a biased two-conductor traveling-wave transmission line (54, 56, 58, 68) having a uranium cathode (60) and a phosphor anode (62) as respective parts of the two conductors. A charge line and Auston switch assembly (70, 72, 74) launch an electric field pulse along the transmission line. Neutrons striking the uranium cathode at a location where the field pulse is passing, are enabled to strike the phosphor anode and produce light that is recorded on photographic film (64). The transmission line may be variously configured to achieve specific experimental goals.

Wang, Ching L. (Livermore, CA)

1987-01-01T23:59:59.000Z

146

Nondestructive Evaluation on Hydrided LWR Fuel Cladding by Small Angle Incoherent Neutron Scattering of Hydrogen  

SciTech Connect

A non-destructive neutron scattering method was developed to precisely measure the uptake of total hydrogen in nuclear grade Ziraloy-4 cladding. The hydriding apparatus consists of a closed stainless steel vessel that contains Zr alloy specimens and H gas. By controlling the initial H gas pressure in the vessel and the temperature profile, target H concentrations from tens of ppm to a few thousands of wppm have been successfully achieved. Following H charging, the H content of the hydrided specimens was measured using the vacuum hot extraction method (VHE), by which the samples with desired H concentration were selected for the neutron study. Small angle neutron incoherent scattering (SANIS) were performed in the High Flux Isotope Reactor at Oak Ridge national Laboratory (ORNL). Our study indicates that a very small amount ( 20 ppm) H in commercial Zr cladding can be measured very accurately in minutes for a wide range of H concentration by a nondestructive method. The H distribution in a tube sample was obtained by scaling the neutron scattering rate with a factor, which is determined by calibration process with direct chemical analysis method on the specimen. This scale factor can be used for future test with unknown H concentration, thus provide a nondestructive method for absolute H concentration determination.

Yan, Yong [ORNL; Qian, Shuo [ORNL; Littrell, Ken [ORNL; Parish, Chad M [ORNL; Bell, Gary L [ORNL; Plummer, Lee K [ORNL

2013-01-01T23:59:59.000Z

147

Spallation Neutron Source The Spallation Neutron Source (SNS)  

NLE Websites -- All DOE Office Websites (Extended Search)

F/gim F/gim Spallation Neutron Source The Spallation Neutron Source (SNS) gives researchers more detailed informa- tion on the structure and dynamics of physical and biological materials than ever before possible. This accelerator- based facility provides the most intense pulsed neutron beams in the world. Scien- tists are able to count scattered neutrons, measure their energies and the angles at which they scatter, and map their final positions. SNS enables measurements of greater sensitivity, higher speed, higher resolution, and in more complex sample environments than have been possible at existing neutron facilities. Future Growth SNS was designed from the outset to accommodate a second target station, effectively doubling the capacity of the

148

Neutron skins and neutron stars  

Science Journals Connector (OSTI)

Background: The neutron skin of a heavy nucleus as well as many neutron-star properties are highly sensitive to the poorly constrained density dependence of the symmetry energy.Purpose: To provide for the first time meaningful theoretical errors and to assess the degree of correlation between the neutron-skin thickness of 208Pb and several neutron-star properties.Methods: A proper covariance analysis based on the predictions of an accurately calibrated relativistic functional “FSUGold” is used to quantify theoretical errors and correlation coefficients.Results: We find correlation coefficients of nearly 1 (or ?1) between the neutron-skin thickness of 208Pb and a host of observables of relevance to the structure, dynamics, and composition of neutron stars.Conclusions: We suggest that a follow-up Lead Radius Experiment (PREX) measurement, ideally with a 0.5% accuracy, could significantly constrain the equation of state of neutron-star matter.

F. J. Fattoyev and J. Piekarewicz

2012-07-05T23:59:59.000Z

149

Shock Tube Design  

E-Print Network (OSTI)

. The driver section drives the shock-front because of high pressured driving fluid contained in it. It contains the diaphragm holders, and the mechanisms that control their rupture along with an end cap. The driven section is the portion of the tube where... and to withstand higher pressures. The driver sections named driver-1 and driver-2 are shown in Figure 1. 10 Figure 1. Section view of the driver section. The end cap on the rear driver section is made of thicker material than the side walls because...

Koppenberger, Peter K.

2010-07-14T23:59:59.000Z

150

Neutron Scattering Tutorials | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Scattering Tutorials SHARE Neutron Scattering Tutorials The following lectures were presented at the 2011 and 2010 National School on Neutron & X-Ray Scattering. This...

151

Neutron detector  

DOE Patents (OSTI)

A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

Stephan, Andrew C. (Knoxville, TN); Jardret; Vincent D. (Powell, TN)

2011-04-05T23:59:59.000Z

152

Ion plated electronic tube device  

DOE Patents (OSTI)

An electronic tube and associated circuitry which is produced by ion plating techniques. The process is carried out in an automated process whereby both active and passive devices are produced at very low cost. The circuitry is extremely reliable and is capable of functioning in both high radiation and high temperature environments. The size of the electronic tubes produced are more than an order of magnitude smaller than conventional electronic tubes.

Meek, T.T.

1983-10-18T23:59:59.000Z

153

Neutron scattering instrumentation at reactor based installations  

Science Journals Connector (OSTI)

During the past decade neutron scattering techniques have been applied to an increasingly wide range of scientific problems. Concurrently a number of substantial improvements of neutron scattering instrumentation have occurred to stimulate this trend. In this article several such developments which have occurred at reactor?based installations are described. Individual spectrometer components which are discussed in some detail include: neutron?optical devices such as guide tubes supermirrors and multilayer systems; neutronmonochromators with optimum reflectivity mosaic and focusing characteristics; position?sensitive detectors of several types; and equipment required for neutronpolarizationanalysis. Several novel spectrometers which have enhanced the role of neutron scattering during the past ten years are also described. These include spectrometers for small?angle scattering backscattering and neutron spin echo. An extensive bibliography is included which covers both early and more recent developments.

Roger Pynn

1984-01-01T23:59:59.000Z

154

Slow neutron leakage spectra from spallation neutron sources  

SciTech Connect

An efficient technique is described for Monte Carlo simulation of neutron beam spectra from target-moderator-reflector assemblies typical of pulsed spallation neutron sources. The technique involves the scoring of the transport-theoretical probability that a neutron will emerge from the moderator surface in the direction of interest, at each collision. An angle-biasing probability is also introduced which further enhances efficiency in simple problems. These modifications were introduced into the VIM low energy neutron transport code, representing the spatial and energy distributions of the source neutrons approximately as those of evaporation neutrons generated through the spallation process by protons of various energies. The intensity of slow neutrons leaking from various reflected moderators was studied for various neutron source arrangements. These include computations relating to early measurements on a mockup-assembly, a brief survey of moderator materials and sizes, and a survey of the effects of varying source and moderator configurations with a practical, liquid metal cooled uranium source Wing and slab, i.e., tangential and radial moderator arrangements, and Be vs CH/sub 2/ reflectors are compared. Results are also presented for several complicated geometries which more closely represent realistic arrangements for a practical source, and for a subcritical fission multiplier such as might be driven by an electron linac. An adaptation of the code was developed to enable time dependent calculations, and investigated the effects of the reflector, decoupling and void liner materials on the pulse shape.

Das, S.G.; Carpenter, J.M.; Prael, R.E.

1980-02-01T23:59:59.000Z

155

Neutron Scattering  

Science Journals Connector (OSTI)

... Magnetic Neutron Diffraction By Yurii A. Izyumov and Ruslan P. Ozerov. Translated from the Russian. ... York; Heydon: London, June 1970.) 350s; $37.50; 150 DM.

G. L. SQUIRES

1970-12-05T23:59:59.000Z

156

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Biology & Medicine Archive Biology & Medicine Archive Research Highlights Biology & Medicine Archive Small-Angle Neutron Scattering Team Finds Structural Differences in Sindbis Virus Particles from Different Host Species (2010) Published Work: "The Structure of Sindbis Virus Produced from Vertebrate and Invertebrate Hosts as Determined by Small-Angle Neutron Scattering" Contact: Flora Meilleur Targeted Drug Delivery Systems Studies of the unique structure of synthetic molecules will help in the development of drugs that can target diseased areas of the body. This researched on dendrimers revealed how molecules function within solutions at different pH levels. (2008) Research in progress. Contact: Wei-Ren Chen "Intelligent" Polymers for Biomedical Technologies

157

A beam swinger for neutron scattering  

Science Journals Connector (OSTI)

A conceptual design is presented for a system that provides for varying the angle of incidence of neutron flux on a scattering target. This makes possible the use of long flight paths for time?of?flight spectroscopy of scattered neutrons. The system is also applicable to measurements of neutron induced charged particle reactions. Special emphasis is placed on the energy range of 50–200 MeV.

C. D. Goodman

1985-01-01T23:59:59.000Z

158

Hydraulic testing of modified neutron source rod in type Q septifoil  

SciTech Connect

A Type Q septifoil, two modified partial length control rods, four full length control rods, a source rod containing a dummy neutron source and a guide tube assembly were installed in the Long Term Flow Facility (LTFF) of the HTL. The water level inside the guide tubes over the septifoil was measured by the use of sight tubes connected to pressure taps on the guide tubes or by pressure gages. Pressures were measured at tank bottom and inside the septifoil. The target tank bottom pressure for the experiments was 12.76 psig which gives the same no-flow freeboard in the LTFF as a blanket gas pressure of 5.00 psig in K Reactor. The first series of tests was performed with the existing source rods under a previous Task Plan, 92-057-1. The source rod was kept fully seated during testing to reduce the effect of the flow path through the source rod. Freeboards were adequate during the conditions of normal operation, but inadequate during scram conditions. The minimum freeboard measured during a scram for a septifoil flow of 106 gpm was 20 inches and 7 inches for 120 gpm, adjusted to the target tank bottom pressure. During a control rod scram the full length control rods are driven into the reactor core as a gauge. The reason that freeboards are small during a scram is that the rods pass through positions that tend to reduce freeboard, rather than the velocity of the rods having a negative effect. In fact, a lower freeboard occurs if the rod are held motionless at certain positions. The second series of tests was performed with a modified source rod in which the flow path through the source rod was eliminated. for these tests the source rod was lifted after the control rods had been positioned, the usual procedure in SRS Reactors. The source rod design change increased freeboards such that they were adequate under all conditions.

Steimke, J.L.; Fowley, M.D.

1992-10-01T23:59:59.000Z

159

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis ... Describes the science and techniques of neutron activation analysis. ...

H. R. Lukens

1967-01-01T23:59:59.000Z

160

A Permanent-Magnet Microwave Ion Source for a Compact High-Yield Neutron Generator  

SciTech Connect

We present recent work on the development of a microwave ion source that will be used in a high-yield compact neutron generator for active interrogation applications. The sealed tube generator will be capable of producing high neutron yields, 5x1011 n/s for D-T and ~;;1x1010 n/s for D-D reactions, while remaining transportable. We constructed a microwave ion source (2.45 GHz) with permanent magnets to provide the magnetic field strength of 87.5 mT necessary for satisfying the electron cyclotron resonance (ECR) condition. Microwave ion sources can produce high extracted beam currents at the low gas pressures required for sealed tube operation and at lower power levels than previously used RF-driven ion sources. A 100 mA deuterium/tritium beam will be extracted through a large slit (60x6 mm2) to spread the beam power over a larger target area. This paper describes the design of the permanent-magnet microwave ion source and discusses the impact of the magnetic field design on the source performance. The required equivalent proton beam current density of 40 mA/cm2 was extracted at a moderate microwave power of 400 W with an optimized magnetic field.

Waldmann, Ole; Ludewigt, Bernhard

2010-10-11T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

SNS Target R&D Presented by  

E-Print Network (OSTI)

since been resolved ­ QA program would have to be very stringent for long lifetime Second target station implemented #12;11 Managed by UT-Battelle for the U.S. Department of Energy Spallation Neutron Source

McDonald, Kirk

162

Alternative Neutron Detection Testing Summary  

SciTech Connect

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. Most currently deployed radiation portal monitors (RPMs) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large area neutron detector. This type of neutron detector is used in the TSA and other RPMs installed in international locations and in the Ludlum and Science Applications International Corporation RPMs deployed primarily for domestic applications. There is a declining supply of 3He in the world and, thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated wavelength-shifting plastic fibers. Reported here is a summary of the testing carried out at Pacific Northwest National Laboratory on these technologies to date, as well as measurements on 3He tubes at various pressures. Details on these measurements are available in the referenced reports. Sponsors of these tests include the Department of Energy (DOE), Department of Homeland Security (DHS), and the Department of Defense (DoD), as well as internal Pacific Northwest National Laboratory funds.

Kouzes, Richard T.; Ely, James H.; Erikson, Luke E.; Kernan, Warnick J.; Lintereur, Azaree T.; Siciliano, Edward R.; Stromswold, David C.; Woodring, Mitchell L.

2010-04-08T23:59:59.000Z

163

Study on neutron emission from 2.2?kJ plasma focus device  

SciTech Connect

The neutron emission from a low energy (2.2?kJ) plasma focus device operated in deuterium medium has been investigated by employing photo-multiplier tube (PMT) and bubble dosimeter. The neutron emission is found to be pressure dependent and anisotropic in nature. In most cases of plasma focus shots, the PMT signal shows double pulses of neutron emission with different intensities and widths. An interesting relation between intensity of hard X-ray and neutron emission is also observed.

Talukdar, N.; Neog, N. K.; Borthakur, T. K., E-mail: tkborthakur@yahoo.co.uk [Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782402, Kamrup, Assam (India)

2014-06-15T23:59:59.000Z

164

Neutron Microscope  

Science Journals Connector (OSTI)

We report successful operation of a neutron microscope using ultracold neutrons at the high-flux reactor at Grenoble. A sharp, achromatic image of an object slit was obtained at a magnification of 50. The measured resolution of 0.1 mm was limited mainly by the available beam intensity, not by aberrations.

P. Herrmann; K. -A. Steinhauser; R. Gähler; A. Steyerl; W. Mampe

1985-05-06T23:59:59.000Z

165

Neutron scattering  

Science Journals Connector (OSTI)

... statements that the EMBL outstation in Grenoble "[has an] uncertain future" and that "neutrons have not turned out to be particularly useful for biologists" in Peter Newmark's ... on the European Molecular Biology Laboratory (Nature 338, 724; 1989) require some comment.Neutron ...

S. CUSACK; B. JACROT; R. LEBERMAN; R. MAY; P. TlMMINS; G. ZACCAI

1989-06-01T23:59:59.000Z

166

SHORT-TUBE SUBCRITICAL FLOW Enerag Division  

E-Print Network (OSTI)

#12;SHORT-TUBE SUBCRITICAL FLOW Y. C. Mei Enerag Division Oak Ridge National Laboratory Oak Ridge-tube subcritical flow. For short tubes used as refrigerant expansion devices, the orifice model is found inadequate-TUBE SUBCRITICAL FLOW INTRODUCTION Much theoretical and experimental work regarding short tube fluid flow has

Oak Ridge National Laboratory

167

2014 Tube -1 STANDING WAVES  

E-Print Network (OSTI)

2014 Tube - 1 STANDING WAVES IN AN AIR COLUMN The objective of the experiment is: · To study the harmonic structure of standing waves in an air column. APPARATUS: Computer, FFTScope software, PC speaker, meterstick, sound tube apparatus, thermometer, microphone INTRODUCTION traveling wave of sinusoidal shape

Glashausser, Charles

168

Helical tubes in crowded environments  

Science Journals Connector (OSTI)

When placed in a crowded environment, a semiflexible tube is forced to fold so as to make a more compact shape. One compact shape that often arises in nature is the tight helix, especially when the tube thickness is of comparable size to the tube length. In this paper we use an excluded volume effect to model the effects of crowding. This gives us a measure of compactness for configurations of the tube, which we use to look at structures of the semiflexible tube that minimize the excluded volume. We focus most of our attention on the helix and which helical geometries are most compact. We found helices of specific pitch to radius ratio 2.512 to be optimally compact. This is the same geometry that minimizes the global curvature of the curve defining the tube. We further investigate the effects of adding a bending energy or multiple tubes to begin to explore the more complete space of possible geometries a tube could form.

Yehuda Snir and Randall D. Kamien

2007-05-18T23:59:59.000Z

169

SANS -Small Angle Neutron Scattering Tcnica de difrao  

E-Print Network (OSTI)

SANS - Small Angle Neutron Scattering Técnica de difração informações sobre tamanho e forma de- Neutrons are created in the centre of the target station when the beam of high energy protons collides by evaporating nuclear particles, mainly neutrons, in all directions. Each proton produces approximately 15

Loh, Watson

170

Tubing pressurized firing apparatus for a tubing conveyed perforating gun  

SciTech Connect

A tubing pressurized firing apparatus is shown for use with a tubing conveyed perforating gun of the type used to perforate a cased well bore. The firing apparatus has a tubular body with an upper end for connection in the well tubing string and with a lower end for connection to a well perforating gun. An inner mandrel is slidably mounted within the tubular body and has a ball seat formed in the interior bore thereof for receiving a ball dropped through the well tubing string. The ball and ball seat together form a pressure tight seal whereby tubing pressure in the well tubing string acts on the inner mandrel to slide the mandrel downwardly within the tubular body. A cocking mechanism located below the inner mandrel within the body includes a lockout member which is initially positioned between a detonating pin and a percussion detonator. The cocking mechanism is actuated by downward sliding movement of the inner mandrel to move the lockout member from between the detonating pin and percussion detonator whereby a subsequent release of tubing pressure and upward sliding movement of the inner mandrel exposes the detonating pin to the percussion detonator to actuate the detonator and fire the perforating gun.

Davies, D. L.

1985-11-26T23:59:59.000Z

171

Divertor target for magnetic containment device  

DOE Patents (OSTI)

In a plasma containment device of a type having superconducting field coils for magnetically shaping the plasma into approximately the form of a torus, an improved divertor target for removing impurities from a "scrape off" region of the plasma comprises an array of water cooled swirl tubes onto which the scrape off flux is impinged. Impurities reflected from the divertor target are removed from the target region by a conventional vacuum getter system. The swirl tubes are oriented and spaced apart within the divertor region relative to the incident angle of the scrape off flux to cause only one side of each tube to be exposed to the flux to increase the burnout rating of the target. The divertor target plane is oriented relative to the plane of the path of the scrape off flux such that the maximum heat flux onto a swirl tube is less than the tube design flux. The containment device is used to contain the plasma of a tokamak fusion reactor and is applicable to other long pulse plasma containment systems.

Luzzi, Jr., Theodore E. (Garden City, NY)

1982-01-01T23:59:59.000Z

172

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network (OSTI)

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing sci...

O'Shaughnessy, C M; Schelhammer, K W; Swank, C M; Seo, P -N; Huffman, P R; Dzhosyuk, S N; Mattoni, C E H; Yang, L; Doyle, J M; Coakley, K J; Thompson, A K; Mumm, H P; Lamoreaux, S K; Yang, G

2009-01-01T23:59:59.000Z

173

Neutron Polarization  

Science Journals Connector (OSTI)

The production of polarized neutrons in magnetized iron has been studied, using the intense neutron beams available at the Argonne heavy water pile. The theoretical work of Halpern et al., used as a guide in the experiments, has been checked in many respects, with the exception that the polarization cross section p has a measured value of 3.15 barns compared to the theoretical 1 barn. The application of neutron polarization to the measurement of the approach to saturation in ferromagnets is described and preliminary results are reported.

D. J. Hughes; J. R. Wallace; R. H. Holtzman

1948-06-01T23:59:59.000Z

174

Combustion-thermoelectric tube  

SciTech Connect

In direct combustion-thermoelectric energy conversion, direct fuel injection and reciprocation of the air flowing in a solid matrix are combined with the solid conduction to allow for obtaining super-adiabatic temperatures at the hot junctions. While the solid conductivity is necessary, the relatively large thermal conductivity of the available high-temperature thermoelectric materials (e.g., Si-Ge alloys) results in a large conduction loss from the hot junctions and deteriorates the performance. Here a combustion-thermoelectric tube is introduced and analyzed. Radially averaged temperatures are used for the fluid and solid phases. A combination of external cooling of the cold junctions, and direct injection of the fuel, has been used to increase the energy conversion efficiency for low thermal conductivity, high-melting temperature thermoelectric materials. The parametric study (geometry, flow, stoichiometry, materials) shows that with the current high figure of merit, high temperature Si{sub 0.7}Ge{sub 0.3} properties, a conversion efficiency of about 11% is achievable. With lower thermal conductivities for these high-temperature materials, efficiencies about 25% appear possible. This places this energy conversion in line with the other high efficiency, direct electric power generation methods.

Park, C.W.; Kaviany, M.

1999-07-01T23:59:59.000Z

175

Method of making straight fuel cell tubes  

DOE Patents (OSTI)

A method and an apparatus for making straight fuel cell tubes are disclosed. Extruded tubes comprising powders of fuel cell material and a solvent are dried by rotating the extruded tubes. The rotation process provides uniform circumferential drying which results in uniform linear shrinkage of the tubes. The resultant dried tubes are very straight, thereby eliminating subsequent straightening steps required with conventional processes. The method is particularly useful for forming inner air electrode tubes of solid oxide fuel cells.

Borglum, Brian P. (Edgewood, PA)

2001-01-01T23:59:59.000Z

176

Thermal neutron detection system  

DOE Patents (OSTI)

According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

2000-01-01T23:59:59.000Z

177

Neutron Checkup  

Science Journals Connector (OSTI)

Neutron activation analysis is yet another technique in the arsenal of diagnostic methods that physicians can draw on to examine the health of their patients. The University of Washington's school of medicine in Seattle is the first facility in the ...

1969-11-10T23:59:59.000Z

178

Neutron Reflectometry  

Science Journals Connector (OSTI)

Neutron reflectometry is a relatively new technique [1,2]. In the last years, it has been extensively used for solving soft matter problems like polymer mixing [3,4] or the structure of liquids at the surface [5,

Claude Fermon; Frédéric Ott; Alain Menelle

1999-01-01T23:59:59.000Z

179

Neutron Tomography and Space  

E-Print Network (OSTI)

Kevin Shields, “Optimization of neutron tomography for rapidNEUTRON TOMOGRAPHY AND SPACE Hal Egbert, Ronald Walker, R.industrial applications[1]. Neutron Computed Tomography was

Egbert, Hal; Walker, Ronald; Flocchini, R.

2007-01-01T23:59:59.000Z

180

Neutron range spectrometer  

DOE Patents (OSTI)

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

Manglos, S.H.

1988-03-10T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Inspection of the objects on the sea floor by using 14 MeV tagged neutrons  

SciTech Connect

Variety of objects found on the sea floor needs to be inspected for the presence of materials which represent the threat to the environment and to the safety of humans. We have demonstrated that the sealed tube 14 MeV neutron generator with the detection of associated alpha particles can be used underwater when mounted inside ROV equipped with the hydraulic legs and variety of sensors for the inspection of such objects for the presence of threat materials. Such a system is performing the measurement by using the NaI gamma detector and an API-120 neutron generator which could be rotated in order to maximize the inspected target volume. The neutron beam intensity during the 10-30 min. measurements is usually 1 x 10{sup 7} n/s in 4{pi}. In this report the experimental results for some of commonly found objects containing TNT explosive or its simulant are presented. The measured gamma spectra are dominant by C, O and Fe peaks enabling the determination of the presence of explosives inside the ammunition shell. Parameters influencing the C/O ratio are discussed in some details. (authors)

Valkovic, V. [A.C.T.d.o.o., Prilesje 4, Zagreb (Croatia); Sudac, D.; Obhodas, J. [Dept. of Experimental Physics, Inst. Ruder Boskovic, Zagreb (Croatia); Matika, D. [Inst. for Researches and Development of Defense Systems, Zagreb (Croatia); Kollar, R. [A.C.T.d.o.o., Prilesje 4, Zagreb (Croatia); Nad, K.; Orlic, Z. [Dept. of Experimental Physics, Inst. Ruder Boskovic, Zagreb (Croatia)

2011-07-01T23:59:59.000Z

182

Compact, energy EFFICIENT neutron source: enabling technology for various applications  

SciTech Connect

A novel neutron source comprising of a deuterium beam (energy of about 100 KeV) injected into a tube filled with tritium gas and/or tritium plasma that generates D-T fusion reactions, whose products are 14.06 MeV neutrons and 3.52 MeV alpha particles, is described. At the opposite end of the tube, the energy of deuterium ions that did not interact is recovered. Beryllium walls of proper thickness can be utilized to absorb 14 MeV neutrons and release 2-3 low energy neutrons. Each ion source and tube forms a module. Larger systems can be formed from multiple units. Unlike currently proposed methods, where accelerator-based neutron sources are very expensive, large, and require large amounts of power for operation, this neutron source is compact, inexpensive, easy to test and to scale up. Among possible applications for this neutron source concept are sub-critical nuclear breeder reactors and transmutation of radioactive waste.

Hershcovitch, A.; Roser, T.

2009-12-01T23:59:59.000Z

183

Rotating Target Development for SNS Second Target Station  

SciTech Connect

A rotating target for the second target station (STS) at SNS has been identified as an option along with a mercury target. Evaluation of the rotating target alternative for STS has started at 1.5 MW which is considered an upper bound for the power. Previous preconceptual design work for a 3 MW rotating target is being modified for the lower power level. Transient thermal analysis for a total loss of active water cooling has been done for a simplified 2D model of the target and shielding monolith which shows that peak temperatures are well below the level at which tungsten vaporization by steam could exceed site boundary dose limits. Design analysis and integration configuration studies have been done for the target-moderator-reflector assembly which maximizes the number of neutron beam lines and provides for replacement of the target and moderators. Target building hot cell arrangement for this option will be described. An option for operation in rough vacuum without a proton beam window using Ferro fluid seals on a vertical shaft is being developed. A full scale prototypic drive module based on the 3 MW preconceptual design has been fabricated and successfully tested with a shaft and mock up target supplied by the ESS-Bilbao team. Overall planning leading to decision between mercury and the rotating target in 2011 will be discussed

McManamy, Thomas J [ORNL; Rennich, Mark J [ORNL; Crawford, Roy K [ORNL; Geoghegan, Patrick J [ORNL; Janney, Jim G [ORNL

2010-01-01T23:59:59.000Z

184

Tube-wave seismic imaging  

DOE Patents (OSTI)

The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

Korneev, Valeri A [LaFayette, CA

2009-05-05T23:59:59.000Z

185

Tube-wave seismic imaging  

DOE Patents (OSTI)

The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

Korneev, Valeri A. (Lafayette, CA); Bakulin, Andrey (Houston, TX)

2009-10-13T23:59:59.000Z

186

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method  

DOE Patents (OSTI)

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0.times.10.sup.9 neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use.

Yoon, Woo Y. (Idaho Falls, ID); Jones, James L. (Idaho Falls, ID); Nigg, David W. (Idaho Falls, ID); Harker, Yale D. (Idaho Falls, ID)

1999-01-01T23:59:59.000Z

187

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method  

DOE Patents (OSTI)

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.

Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.

1999-05-11T23:59:59.000Z

188

Secondary electron ion source neutron generator  

DOE Patents (OSTI)

A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter. The target contains occluded deuterium, tritium, or a mixture thereof

Brainard, John P. (Albuquerque, NM); McCollister, Daryl R. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

189

Secondary electron ion source neutron generator  

DOE Patents (OSTI)

A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter is disclosed. The target contains occluded deuterium, tritium, or a mixture thereof. 4 figs.

Brainard, J.P.; McCollister, D.R.

1998-04-28T23:59:59.000Z

190

Large passive pressure tube light water reactor with voided calandria  

SciTech Connect

A reactor concept has been developed that can survive loss-of-coolant accidents (LOCAs) without scram and without replenishing primary coolant inventory while maintaining safe temperature limits on the fuel and pressure tube. The proposed concept is a pressure tube reactor of similar design to Canada deuterium uranium reactors but differing in three key aspects. First, a solid silicon carbide-coated graphite fuel matrix is used in place of fuel pin bundles to enable the dissipation of decay heat from the fuel in the absence of primary coolant. Second, the heavy water coolant in the pressure tubes is replaced by light water, which also serves as the moderator. Finally, the calandria tank, surrounded by a graphite reflector, contains a low-pressure gas instead of heavy water moderator, and this normally voided calandria is connected to a light water heat sink. The cover gas displaces the light water from the calandria during normal operation while during a LOCA or loss of heat sink accident, it allows passive calandria flooding. Calandria flooding also provides redundant and diverse reactor shutdown. The fuel elements can operate under post-critical-heat-flux conditions even at full power without exceeding fuel design limits. The heterogeneous arrangement of the fuel and moderator ensures a negative void coefficient under all circumstances. Although light water is used as both coolant and moderator, the reactor exhibits a high degree of neutron thermalization and a large prompt neutron lifetime, similar to D{sub 2}O-moderated cores. Moreover, the extremely large neutron migration length results in a strongly coupled core with a flat thermal flux profile and inherent stability against xenon spatial oscillations.

Hejzlar, P.; Todreas, N.E.; Driscoll, M.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Nuclear Engineering

1996-02-01T23:59:59.000Z

191

E-Print Network 3.0 - aluminium 26 target Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

target, a large D2O moderator and a solid... a spallation target made of lead- filled zircaloy tubes 1,2. The proton beam is pulsed by deflecting the beam... identical beam...

192

Neutron scattering studies of carbon nanotubes  

Science Journals Connector (OSTI)

We report on neutron scattering studies of single wall carbon nanotubes (SWNT). Small angle scattering was used to investigate the structure of SWNT suspensions. Diffraction data were compared to calculations on finite-size bundles of SWNT in order to estimate the distribution of tube diameters. Lastly we present an inelastic neutron scattering study of the density of phonon states in SWNT. In the frequency range of intramolecular modes the measured spectrum is found to be in good agreement with that calculated on an isolated (10 10) nanotube.

E. Anglaret; S. Rols; J. L. Sauvajol

1999-01-01T23:59:59.000Z

193

Neutron Repulsion  

E-Print Network (OSTI)

Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding how: a.) The Sun generates and releases neutrinos, energy and solar-wind hydrogen and helium; b.) An inhabitable planet formed and life evolved around an ordinary-looking star; c.) Continuous climate change - induced by cyclic changes in gravitational interactions of the Sun's energetic core with planets - has favored survival by adaptation.

Oliver K. Manuel

2011-02-08T23:59:59.000Z

194

Fast-Neutron Handbook  

Science Journals Connector (OSTI)

... FAST neutron physics, in the present context, concerns the study of interactions of atomic nuclei with neutrons ...

J. H. MONTAGUE

1961-06-10T23:59:59.000Z

195

Cyclotron-based neutron source for BNCT  

SciTech Connect

Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)

2013-04-19T23:59:59.000Z

196

Neutron Scattering User Program | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

User Program SHARE Neutron Scattering Can Benefit Your Research Neutron scattering has applications in almost every technical and scientific field, from biology and chemistry to...

197

Using laser-driven neutrons to stop nuclear smugglers  

NLE Websites -- All DOE Office Websites (Extended Search)

Using laser-driven neutrons to stop nuclear smugglers Using laser-driven neutrons to stop nuclear smugglers Using laser-driven neutrons to stop nuclear smugglers Researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. June 4, 2013 A burst of laser energy 50 times greater than the worldwide output of electrical power slams into an extremely thin foil target to produce neutrons at Los Alamos National Laboratory's TRIDENT laser facility during a recent experiment, which proved that laser-driven neutrons can be used to detect and interdict smuggled nuclear materials. A burst of laser energy 50 times greater than the worldwide output of electrical power slams into an extremely thin foil target to produce neutrons at Los Alamos National Laboratory's TRIDENT laser facility during

198

Neutron Polarization  

Science Journals Connector (OSTI)

Experiments for the determination of the polarization cross section p of iron with monochromatic and non-monochromatic neutrons are described. The absolute value of p as well as its dependence on the neutron velocity is found to be in good agreement with the recent calculations of Steinberger and Wick and also with other experiments. For a complex neutron spectrum originating from a paraffin moderator p¯ is found to be (2.35±0.1)×10-24 cm2 in agreement with previous investigations. It is shown that the larger value of 3.15×10-24 cm2 found by Hughes, Wallace, and Holtzman must be due to spectral differences. The approach of the magnetization of iron towards saturation is also investigated.

J. Fleeman; D. B. Nicodemus; H. H. Staub

1949-12-15T23:59:59.000Z

199

Introduction to Neutron Coincidence Counter Design Based on Boron-10  

SciTech Connect

The Department of Energy Office of Nonproliferation Policy (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is ultimately to design, build and demonstrate a boron-lined proportional tube based alternative system in the configuration of a coincidence counter. This report, providing background information for this project, is the deliverable under Task 1 of the project.

Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.

2012-01-22T23:59:59.000Z

200

Thermal Neutron Imaging in an Active Interrogation Environment  

SciTech Connect

We have developed a thermal-neutron coded-aperture imager that reveals the locations of hydrogenous materials from which thermal neutrons are being emitted. This imaging detector can be combined with an accelerator to form an active interrogation system in which fast neutrons are produced in a heavy metal target by means of excitation by high energy photons. The photo-induced neutrons can be either prompt or delayed, depending on whether neutron-emitting fission products are generated. Provided that there are hydrogenous materials close to the target, some of the photo-induced neutrons slow down and emerge from the surface at thermal energies. These neutrons can be used to create images that show the location and shape of the thermalizing materials. Analysis of the temporal response of the neutron flux provides information about delayed neutrons from induced fission if there are fissionable materials in the target. The combination of imaging and time-of-flight discrimination helps to improve the signal-to-background ratio. It is also possible to interrogate the target with neutrons, for example using a D-T generator. In this case, an image can be obtained from hydrogenous material in a target without the presence of heavy metal. In addition, if fissionable material is present in the target, probing with fast neutrons can stimulate delayed neutrons from fission, and the imager can detect and locate the object of interest, using appropriate time gating. Operation of this sensitive detection equipment in the vicinity of an accelerator presents a number of challenges, because the accelerator emits electromagnetic interference as well as stray ionizing radiation, which can mask the signals of interest.

Vanier, Peter E. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Forman, Leon [Ion Focus Technology, Inc., Miller Place, NY 11764 (United States); Norman, Daren R. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

2009-03-10T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

The Neutron-Proton and Neutron-Carbon Scattering Cross Sections for Fast Neutrons  

Science Journals Connector (OSTI)

An experimental investigation of the total scattering cross section of hydrogen and carbon for neutrons of energies 0.35 to 6.0 Mev is reported. Neutrons of discrete energies were produced by particle bombardment of lithium, carbon, and heavy water targets. Transmissions of cyclohexane (C6H12) and graphite scatterers under conditions of good geometry were measured. Results for ?s(H) are compared with the theoretical interpretations of Bohm and Richman in a later paper and to the experimental results of D. Frisch at lower energies in a companion paper. It is estimated that ?s(H) and ?s(C) are determined to approximately five percent.

Carl L. Bailey; William E. Bennett; Thor Bergstralth; Richard G. Nuckolls; Hugh T. Richards; John H. Williams

1946-11-01T23:59:59.000Z

202

Fracture toughness evaluation for N Reactor pressure tubes of Zircaloy-2 using the electric-potential method  

SciTech Connect

Zircaloy is commonly used for the cladding or pressure tubes in commercial reactors because of its strength, corrosion resistance, and low absorption of thermal neutrons. Fracture toughness test techniques using small samples fabricated from archival materials from N Reactor pressure tubes of Zircaloy-2 were developed to study the factors affecting tube fracture toughness. Compact tension specimen thickness was limited by the wall thickness (7 mm) of the tubes. Specimens (5 mm thick) were prepared for fracture toughness testing and results were analyzed using the J-integral approach. To reduce the high cost of irradiated specimen testing and to more easily precrack specimens remotely, single-specimen potential drop techniques were employed to evaluate the fracture toughness of Zircaloy-2. The initiation fracture toughness was determined from J-R curves, which were constructed by plotting values of J as a function of crack extension computed from the electric-potential calibration curve. The J-R curves obtained from the calibration curve equation fit the blunting line region. The curves also fit heat-tint data well. The effects of neutron fluence and hydrogen content on the fracture toughness of N Reactor pressure tubes were evaluated. Neutron irradiation substantially degraded fracture toughness. Increasing fluence decreased the fracture toughness of the alloy. Hydrogen also decreased fracture toughness, but this effect was insignificant for the pressure tubes tested. 8 refs., 13 figs., 3 tabs.

Huang, F.H.

1991-11-01T23:59:59.000Z

203

Core-tube data logger  

SciTech Connect

Wireline core drilling, increasingly used for geothermal exploration, employs a core-tube to capture a rock core sample during drilling. Three types of core-tube data loggers (CTDL) have been built and tested to date by Sandia national Laboratories. They are: (1) temperature-only logger, (2) temperature/inclinometer logger and (3) heat-shielded temperature/inclinometer logger. All were tested during core drilling operations using standard wireline diamond core drilling equipment. While these tools are designed for core-tube deployment, the tool lends itself to be adapted to other drilling modes and equipment. Topics covered in this paper include: (1) description on how the CTDLs are implemented, (2) the components of the system, (3) the type of data one can expect from this type of tool, (4) lessons learned, (5) comparison to its counterpart and (6) future work.

Henfling, J.A.; Normann, R.A.; Knudsen, S.; Drumheller, D.

1997-01-01T23:59:59.000Z

204

The Neutron  

Science Journals Connector (OSTI)

The writers point out that the postulation of the existence of the "neutron," a combination of an electron and a proton, of small size and low energy would be very useful in explaining a number of atomic and cosmic phenomena. They find that a mathematical treatment based on existing theory leads to indications of such a state but no definite proof.

R. M. Langer and N. Rosen

1931-06-15T23:59:59.000Z

205

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS  

E-Print Network (OSTI)

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS AND POLARIZED 3He R. GOLUB~and Steve K REPORTS (Review Section of Physics Letters) 237, No. 1(1994)1--62. PHYSICS REPORTS North-Holland Neutron electric-dipole moment, ultracold neutrons and polarized 3He R. Goluba and Steve K. Lamoreauxb a

206

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

Wood, J.L.

1992-12-01T23:59:59.000Z

207

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

208

A sensitive neutron spectrometer for the National Ignition Facility  

SciTech Connect

We are developing a sensitive neutron spectrometer for the National Ignition Facility laser at Livermore. The spectrometer will consist of a 1020 channel single-neutron-interaction time-of-flight detector array fielded 23 m from the neutron-producing target. It will use an existing detector array together with upgraded electronics for improved time resolution. Measurements of neutron yield, ion and electron temperatures, and density-radius product are all possible under certain conditions using one-, two-, or three-step reaction processes. The locations of the most important potential sources of scattered neutron backgrounds are determined as the first step in designing collimation to reduce these backgrounds.

Watt, R. G.; Chrien, R. E.; Klare, K. A.; Murphy, T. J.; Wilson, D. C.; Haan, S.

2001-01-01T23:59:59.000Z

209

Thermal neutron imaging in an active interrogation environment  

SciTech Connect

We have developed a thermal-neutron coded-aperture imager that reveals the locations of hydrogenous materials from which thermal neutrons are being emitted. This imaging detector can be combined with an accelerator to form an active interrogation system in which fast neutrons are produced in a heavy metal target by means of xcitation by high energy photons. The photo-induced neutrons can be either prompt or delayed, depending on whether neutronemitting fission products are generated. Provided that there are hydrogenous materials close to the target, some of the photo-induced neutrons slow down and emerge from the surface at thermal energies. These neutrons can be used to create images that show the location and shape of the thermalizing materials. Analysis of the temporal response of the neutron flux provides information about delayed neutrons from induced fission if there are fissionable materials in the target. The combination of imaging and time-of-flight discrimination helps to improve the signal-to-background ratio. It is also possible to interrogate the target with neutrons, for example using a D-T generator. In this case, an image can be obtained from hydrogenous material in a target without the presence of heavy metal. In addition, if fissionable material is present in the target, probing with fast neutrons can stimulate delayed neutrons from fission, and the imager can detect and locate the object of interest, using appropriate time gating. Operation of this sensitive detection equipment in the vicinity of an accelerator presents a number of challenges, because the accelerator emits electromagnetic interference as well as stray ionizing radiation, which can mask the signals of interest.

Vanier,P.E.; Forman, L., and Norman, D.R.

2009-03-10T23:59:59.000Z

210

Neutron Production, Neutron Facilities and Neutron Instrumentation  

Science Journals Connector (OSTI)

...moderators, the fourth is liquid parahydrogen at 20 K. The modular design with target, moderators and reflectors in one unit...live events, like the distribution of the cooling fluid in a refrigerator or measurement of the rate of descent of a gadolinium sphere...

Sven C. Vogel; Hans-Georg Priesmeyer

211

E-Print Network 3.0 - advanced spallation neutron Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

40 Lead-Bismuth Spallation Target Design Yousry Gohar Summary: . Protect the subcritical multiplier from the high-energy protons and neutrons. Contain the spallation... of...

212

An Accelerator Neutron Source for BNCT  

SciTech Connect

The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.

Blue, Thomas, E

2006-03-14T23:59:59.000Z

213

Compact neutron imaging system using axisymmetric mirrors  

DOE Patents (OSTI)

A dispersed release of neutrons is generated from a source. A portion of this dispersed neutron release is reflected by surfaces of a plurality of nested, axisymmetric mirrors in at least an inner mirror layer and an outer mirror layer, wherein the neutrons reflected by the inner mirror layer are incident on at least one mirror surface of the inner mirror layer N times, wherein N is an integer, and wherein neutrons reflected by the outer mirror are incident on a plurality of mirror surfaces of the outer layer N+i times, where i is a positive integer, to redirect the neutrons toward a target. The mirrors can be formed by a periodically reversed pulsed-plating process.

Khaykovich, Boris; Moncton, David E; Gubarev, Mikhail V; Ramsey, Brian D; Engelhaupt, Darell E

2014-05-27T23:59:59.000Z

214

Apparatus for connecting aligned abutted tubes  

DOE Patents (OSTI)

An apparatus for connecting abutted tubes and for maintaining their rotary alignment during connection. The apparatus comprises first and second tubes, a rotation prevention element, a collar and a retainer. Each tube has inside and outside walls, and first and second ends, each end having an inside and outside edge. The first tube has portions defining a first plurality of cavities located at the outside edge of its first end. An external threaded portion is on the outside wall of the first tube and next to the first plurality of cavities. The second tube has portions defining a second plurality of cavities located at the outside edge of its first end. The first plurality has a different number than the second plurality. The first ends of the first and second tubes have substantially the same outside diameter and are abutted during connection so that an orifice is formed whenever first and second tube cavities substantially overlap. A rotation prevension element is placed in the orifice to prevent rotation of the first and second tubes. A collar with an internal threaded portion is slidably disposed about the second tube. The internal threaded portion engages the external threaded portion of the first tube to connect the tubes. A lip connected to the collar prevents separation of the collar from the second tube.

Williams, R.E.

1984-11-29T23:59:59.000Z

215

Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source  

SciTech Connect

High-flux neutrons for imaging and materials analysis applications have typically been provided by accelerator- and reactor-based neutron sources. A novel approach is to use ultraintense (>1018W/cm2) lasers to generate picosecond, collimated neutrons from a dual target configuration. In this article, the production capabilities of present and upcoming laser facilities are estimated while independently maximizing neutron yields and minimizing beam divergence. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. Tailoring of the incident distribution via laser parameters and microlens focusing modifies the emerging neutrons. Projected neutron yields and distributions are compared to conventional sources, yielding comparable on-target fluxes per discharge, shorter time resolution, larger neutron energies and greater collimation.

C.L. Ellison and J. Fuchs

2010-09-23T23:59:59.000Z

216

Neutron Scattering Facilities 1982  

NLE Websites -- All DOE Office Websites (Extended Search)

NEUTRON SOURCES NEUTRON SOURCES Types of Sources U.S. Sources Available for Users Plans for the Future The Neutron Scattering Society of America (NSSA) SNS/ANL School on Neutron and x-Ray Scattering, June 2011 Jim Rhyne Lujan Neutron Scattering Center Los Alamos National Lab. What do we need to do neutron scattering? * Neutron Source - produces neutrons * Diffractometer or Spectrometer - Allows neutrons to interact with sample - Sorts out discrete wavelengths by monochromator (reactor) or by time of flight (pulse source) - Detectors pick up neutrons scattered from sample * Analysis methods to determine material properties * Brain power to interpret results Sources of neutrons for scattering * Nuclear Reactor - Neutrons produced from fission of 235 U - Fission spectrum neutrons

217

Cold neutron scattering in imperfect deuterium crystals  

E-Print Network (OSTI)

The differential cross sections for cold neutron scattering in mosaic deuterium crystals have been calculated for various target temperatures. The theoretical results are compared with the recent experimental data for the neutron wavelengths $\\lambda\\approx$~1--9~\\AA. It is shown that the structures of observed Bragg peaks can be explained by the mosaic spread of about $3^{\\circ}$ and contributions from a~limited number of crystal orientations. Such a~crystal structure should be also taken into account in ultracold neutron upscattering due to the coherent phonon annihilation in solid deuterium.

Andrzej Adamczak

2010-12-10T23:59:59.000Z

218

New measurement of the scattering cross section of slow neutrons on liquid parahydrogen from neutron transmission  

E-Print Network (OSTI)

Slow neutron scattering provides quantitative information on the structure and dynamics of materials of interest in physics, chemistry, materials science, biology, geology, and other fields. Liquid hydrogen is a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. In particular the rapid drop of the slow neutron scattering cross section of liquid parahydrogen below 14.5~meV is especially interesting and important. We have measured the total cross section and the scattering cross section for slow neutrons with energies between 0.43~meV and 16.1~meV on liquid hydrogen at 15.6~K using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge National Laboratory. At 1~meV this measurement is a factor of 3 below the data from previous work which has been used in the design of liquid hydrogen moderators at slow neutron sources. We describe our measurements, compare them with previous work, and discuss the implications for designing more intense slow neutron sources.

K. B. Grammer; R. Alarcon; L. Barrón-Palos; D. Blyth; J. D. Bowman; J. Calarco; C. Crawford; K. Craycraft; D. Evans; N. Fomin; J. Fry; M. Gericke; R. C. Gillis; G. L. Greene; J. Hamblen; C. Hayes; S. Kucuker; R. Mahurin; M. Maldonado-Velázquez; E. Martin; M. McCrea; P. E. Mueller; M. Musgrave; H. Nann; S. I. Penttilä; W. M. Snow; Z. Tang; W. S. Wilburn

2014-12-12T23:59:59.000Z

219

One- and two-neutron removal reactions from the most neutron-rich carbon isotopes  

E-Print Network (OSTI)

The structure of $^{19,20,22}$C has been investigated using high-energy (about 240 MeV/nucleon) one- and two-neutron removal reactions on a carbon target. Measurements were made of the inclusive cross sections and momentum distributions for the charged residues. Narrow momentum distributions were observed for one-neutron removal from $^{19}$C and $^{20}$C and two-neutron removal from $^{22}$C. Two-neutron removal from $^{20}$C resulted in a relatively broad momentum distribution. The results are compared with eikonal-model calculations combined with shell-model structure information. The neutron-removal cross sections and associated momentum distributions are calculated for transitions to both the particle-bound and particle-unbound final states. The calculations take into account the population of the mass $A-1$ reaction residues, $^{A-1}$C, and, following one-neutron emission after one-neutron removal, the mass $A-2$ two-neutron removal residues, $^{A-2}$C. The smaller contributions of direct two-neutron removal, that populate the $^{A-2}$C residues in a single step, are also computed. The data and calculations are shown to be in good overall agreement and consistent with the predicted shell-model ground state configurations and the one-neutron overlaps with low-lying states in $^{18-21}$C. These suggest significant $\

N. Kobayashi; T. Nakamura; J. A. Tostevin; Y. Kondo; N. Aoi; H. Baba; S. Deguchi; J. Gibelin; M. Ishihara; Y. Kawada; T. Kubo; T. Motobayashi; T. Ohnishi; N. A. Orr; H. Otsu; H. Sakurai; Y. Satou; E. C. Simpson; T. Sumikama; H. Takeda; M. Takechi; S. Takeuchi; K. N. Tanaka; N. Tanaka; Y. Togano; K. Yoneda

2011-11-30T23:59:59.000Z

220

Dosimetry and spectrometry at accelerator based neutron source for boron neutron capture therapy  

Science Journals Connector (OSTI)

An innovative accelerator-based neutron source for boron neutron capture therapy has started operation at the Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using 7Li(p,n)7Be threshold reaction. In the article, techniques to detect neutron and gamma-rays at the facility are described. Gamma radiation is measured with NaI and BGO gamma-spectrometers. The total yield of neutrons is determined by measuring the 477 keV ?-quanta from beryllium decay. For the rough analysis of the generated neutron spectrum we used bubble detectors. As the epithermal neutrons are of interest for neutron capture therapy the NaI detector is used as activation detector. We plan to use a time-of-flight technique for neutron spectra measurement. To realize this technique a new solution of short time neutron generation is proposed.

B. Bayanov; A. Burdakov; A. Kuznetsov; A. Makarov; S. Sinitskii; Yu. Sulyaev; S. Taskaev

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Neutron capture in laser-fusion pellets  

Science Journals Connector (OSTI)

Investigating the feasibility of obtaining slow neutron fluencies sufficient for multiple-capture nucleosynthesis, we have applied a Monte Carlo technique to determine the moderation of neutrons in a superdense laser-energized fusion pellet. We studied pellets of varying chemical composition and structure ranging in size from ?R?1 to 50 g/cm2 and found our results to be rather insensitive to the parametrization of the hydrodynamic motion. That is, the neutron spectra were largely unaffected by reasonable variations of peak density, time of disassembly, and shape of the density profile. A useful method of improving the ratio of moderated to unmoderated neutrons was to dilute the thermonuclear fuel with hydrogen and/or the addition of a beryllium reflector. We also calculated the ratio of fission, neutron capture, and (n, p) reactions in pellets seeded with traces of U238 target material.NUCLEAR REACTIONS Calculated neutron fluxes and neutron-nucleus reactions for parametrized thermonuclear explosions of H2H3 and H2H2 laser-fusion pellets with moderators and target material.

John Henley and Heiner W. Meldner

1975-08-01T23:59:59.000Z

222

Gamma discrimination in pillar structured thermal neutron detectors  

SciTech Connect

Solid-state thermal neutron detectors are desired to replace {sup 3}He tube based technology for the detection of special nuclear materials. {sup 3}He tubes have some issues with stability, sensitivity to microphonics and very recently, a shortage of {sup 3}He. There are numerous solid-state approaches being investigated that utilize various architectures and material combinations. By using the combination of high-aspect-ratio silicon PIN pillars, which are 2 {micro}m wide with a 2 {micro}m separation, arranged in a square matrix, and surrounded by {sup 10}B, the neutron converter material, a high efficiency thermal neutron detector is possible. Besides intrinsic neutron detection efficiency, neutron to gamma discrimination is an important figure of merit for unambiguous signal identification. In this work, theoretical calculations and experimental measurements are conducted to determine the effect of structure design of pillar structured thermal neutron detectors including: intrinsic layer thickness, pillar height, substrate doping and incident gamma energy on neutron to gamma discrimination.

Shao, Q; Radev, R P; Conway, A M; Voss, L F; Wang, T F; Nikolic, R J; Deo, N; Cheung, C L

2012-03-26T23:59:59.000Z

223

Performance of drift tubes under high radiation  

E-Print Network (OSTI)

In this thesis, the aging and the rejuvenation of an ATLAS proportional drift tube are described. Firstly, the Diethorn model of gain is tested using pressure and sense-wire voltage measurements. The drift tube was then ...

Shi, Yue, S.B. Massachusetts Institute of Technology

2005-01-01T23:59:59.000Z

224

Fracture compliance estimation using borehole tube waves  

E-Print Network (OSTI)

We tested two models, one for tube-wave generation and the other for tube-wave attenuation at a fracture intersecting a borehole that can be used to estimate fracture compliance, fracture aperture, and lateral extent. In ...

Bakku, Sudhish Kumar

225

Two phase flow in capillary tubes  

E-Print Network (OSTI)

The flow of two phases, gas and liquid, has been studied in horizontal tubes of capillary diameter. The flow has been primarily studied in the regime where the gas flows as long bubbles separated from the wall of the tube ...

Suo, Mikio

1963-01-01T23:59:59.000Z

226

Neutron Polarization  

Science Journals Connector (OSTI)

The neutron polarization cross section of iron has been measured as a function of energy from 0.7 to 3.3A by two methods: using the single transmission effect in a block of polycrystalline iron at energies selected by a quartz crystal monochromator; and using a single crystal of magnetized magnetite to analyze the beam emerging from the iron polarizer, the magnetite crystal itself serving as monochromator. The measured values are compared with those of other observers and the theoretically expected values. These are found to agree fairly well within the limits of accuracy of the measurements and existing knowledge of the wave function of the iron 3d shell. The two techniques were used also to determine the average polarization (32 percent) as seen by a 1v detector in a beam of reactor neutrons emerging from a 4-cm thick polarizing block of iron. Problems and techniques associated with the measurement of the average polarization of a continuous spectrum are discussed. A simplified experimental treatment of the problem of beam "hardening" is described. A description is given of the use of the magnetic resonance method in conjunction with a single-crystal magnetite analyzer for the measurement of neutron polarization.

C. P. Stanford; T. E. Stephenson; L. W. Cochran; S. Bernstein

1954-04-15T23:59:59.000Z

227

Neutron Gas  

Science Journals Connector (OSTI)

We assume that the neutron-neutron potential is well-behaved and velocity-dependent. We can then apply perturbation theory to find the energy per particle of a neutron gas, in the range of Fermi wave numbers 0.5

J. S. Levinger and L. M. Simmons

1961-11-01T23:59:59.000Z

228

Stability of tube rows in crossflow. [LMFBR  

SciTech Connect

A mathematical model for the instability of tube rows subjected to crossflow is examined. The theoretical model, based on the fluid-force data for a pitch-to-diameter ratio of 1.33, provides additional insight into the instability phenomenon. Tests are also conducted for three sets of tube rows. The effects of mass ratio, tube pitch, damping, detuning and finned tubes are investigated. Theoretical results and experimental data are in good agreement.

Chen, S.S.; Jendrzejczyk, J.A.

1982-10-01T23:59:59.000Z

229

Spring/dimple instrument tube restraint  

DOE Patents (OSTI)

A nuclear fuel assembly for a pressurized water nuclear reactor has a spring and dimple structure formed in a non-radioactive insert tube placed in the top of a sensor receiving instrumentation tube thimble disposed in the fuel assembly and attached at a top nozzle, a bottom nozzle, and intermediate grids. The instrumentation tube thimble is open at the top, where the sensor or its connection extends through the cooling water for coupling to a sensor signal processor. The spring and dimple insert tube is mounted within the instrumentation tube thimble and extends downwardly adjacent the top. The springs and dimples restrain the sensor and its connections against lateral displacement causing impact with the instrumentation tube thimble due to the strong axial flow of cooling water. The instrumentation tube has a stainless steel outer sleeve and a zirconium alloy inner sleeve below the insert tube adjacent the top. The insert tube is relatively non-radioactivated inconel alloy. The opposed springs and dimples are formed on diametrically opposite inner walls of the insert tube, the springs being formed as spaced axial cuts in the insert tube, with a web of the insert tube between the cuts bowed radially inwardly for forming the spring, and the dimples being formed as radially inward protrusions opposed to the springs. 7 figures.

DeMario, E.E.; Lawson, C.N.

1993-11-23T23:59:59.000Z

230

Improving Efficiency of Tube Drawing Bench  

Energy.gov (U.S. Department of Energy (DOE))

Greenville Tube Company, a manufacturer of high-precision, small-diameter stainless steel tubing, conducted an in-house system performance optimization project to improve the efficiency of its No. 6 tube drawing bench. This four-page case study summarizes their experience.

231

Ionization tube simmer current circuit  

DOE Patents (OSTI)

A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

Steinkraus, Jr., Robert F. (Livermore, CA)

1994-01-01T23:59:59.000Z

232

Ionization tube simmer current circuit  

DOE Patents (OSTI)

A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current. 6 figures.

Steinkraus, R.F. Jr.

1994-12-13T23:59:59.000Z

233

Cold cathode vacuum discharge tube  

DOE Patents (OSTI)

A cold cathode vacuum discharge tube, and method for making same, with an interior surface of the trigger probe coated with carbon deposited by carbon vapor deposition (CVD) or diamond-like carbon (DLC) deposition. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging.

Boettcher, Gordon E. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

234

A High Density Polarized Hydrogen Gas Target for Storage Rings  

E-Print Network (OSTI)

A High Density Polarized Hydrogen Gas Target for Storage Rings K. Zapfe \\Lambday , B. Braun z , H of gaseous polarized hydrogen was formed by injecting polarized H atoms (produced by Stern­Gerlach spin separation) into a storage cell consisting of a cylindrical tube open at both ends. The target was placed

235

Neutron Interactions: Q-Equation, Elastic Scattering  

E-Print Network (OSTI)

Since a neutron has no charge it can easily enter into a nucleus and cause a reaction. Neutrons interact primarily with the nucleus of an atom, except in the special case of magnetic scattering where the interaction involves the neutron spin and the magnetic moment of the atom. Because magnetic scattering is of no interest in this class, we can neglect the interaction between neutrons and electrons and think of atoms and nuclei interchangeably. Neutron reactions can take place at any energy, so one has to pay particular attention to the energy variation of the interaction cross section. In a nuclear reactor neutrons can have energies ranging from 10-3 ev (1 mev) to 10 7 ev (10 Mev). This means our study of neutron interactions, in principle, will have to cover an energy range of 10 ten orders of magnitude. In practice we will limit ourselves to two energy ranges, the slowing down region (ev to Kev) and the thermal region (around 0.025 ev). For a given energy region – thermal, epithermal, resonance, fast – not all the possible reactions are equally important. Which reaction is important depends on the target nucleus and the neutron energy. Generally speaking the important types of interactions, in the order of increasing complexity from the standpoint of theoretical

unknown authors

236

ESS liquid-metal target design using computational fluid dynamics  

SciTech Connect

The thermal-hydraulic performance of a spallation neutron source target limits the highest neutron fluxes that can be generated. The current design for the European spallation source consists of a liquid metal encased within a containing shell, wedge-shaped in the direction of the incoming proton beam, with rounded sides in a cross section through a plane normal to the beam.

Dury, T.V. [Paul Scherrer Institute, Villigen (Switzerland)

1997-12-01T23:59:59.000Z

237

Radiobiology of normal rat lung in Boron Neutron Capture Therapy  

E-Print Network (OSTI)

Boron Neutron Capture Therapy (BNCT) is a binary cancer radiation therapy that utilizes biochemical tumor cell targeting and provides a mixed field of high and low Linear Energy Transfer (LET) radiation with differing ...

Kiger, Jingli Liu

2006-01-01T23:59:59.000Z

238

Hypoxia-selective compounds for boron neutron capture therapy  

E-Print Network (OSTI)

Boron neutron capture therapy (BNCT) is a biochemically targeted form of radiotherapy for cancer. In BNCT, a compound labeled with the stable isotope boron-10 is systemically administered, and tumor cells selectively uptake ...

Shah, Jungal (Jugal Kaushik)

2008-01-01T23:59:59.000Z

239

Computational aspects of treatment planning for neutron capture therapy  

E-Print Network (OSTI)

Boron Neutron Capture Therapy (BNCT) is a biochemically targeted form of binary radiation therapy that has the potential to deliver radiation to cancers with cellular dose selectivity. Accurate and efficient treatment ...

Albritton, James Raymond, 1977-

2010-01-01T23:59:59.000Z

240

Publications | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Publications SHARE Publications The Neutron Science publications system contains peer-reviewed publications based on research conducted at ORNL's Neutron Science facilities or...

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Neutron Scattering Facilities  

Science Journals Connector (OSTI)

The past history, present performance and future prospects for neutron scattering facilities will be discussed. Special features of neutron scattering techniques applicable to biological problems will be ... . Th...

D. L. Price

1996-01-01T23:59:59.000Z

242

Turbine nozzle stage having thermocouple guide tube  

DOE Patents (OSTI)

A guide tube is fixed adjacent opposite ends in outer and inner covers of a nozzle stage segment. The guide tube is serpentine in shape between the outer and inner covers and extends through a nozzle vane. An insert is disposed in the nozzle vane and has apertures to accommodate serpentine portions of the guide tube. Cooling steam is also supplied through chambers of the insert on opposite sides of a central insert chamber containing the guide tube. The opposite ends of the guide tube are fixed to sleeves, in turn fixed to the outer and inner covers.

Schotsch, Margaret Jones (Greer, SC); Kirkpatrick, Francis Lawrence (late of Galway, NY); Lapine, Eric Michael (Northwood, NH)

2002-01-01T23:59:59.000Z

243

Calculations of neutron spectra after neutron–neutron scattering  

Science Journals Connector (OSTI)

A direct neutron–neutron scattering length, ann, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of ann will not only help resolve conflicting results of ann by indirect means, but also in comparison to the proton–proton scattering length, app, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum—Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal–thermal and thermal–epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

B E Crawford; S L Stephenson; C R Howell; G E Mitchell; W Tornow; W I Furman; E V Lychagin; A Yu Muzichka; G V Nekhaev; A V Strelkov; E I Sharapov; V N Shvetsov

2004-01-01T23:59:59.000Z

244

Monoenergetic fast neutron reference fields: II. Field characterization  

Science Journals Connector (OSTI)

Monoenergetic neutron reference fields are required for the calibration of neutron detectors and dosemeters for various applications ranging from nuclear physics and nuclear data measurements to radiation protection. In a series of two separate publications the metrological aspects of the production and measurement of fast neutrons are reviewed. In the first part, requirements for the nuclear reactions used to produce neutron fields as well as methods for target characterization and the general layout of reference facilities were discussed. This second part focuses on the most important techniques for field characterization and includes the determination of the neutron fluence as well as the spectral neutron distribution and the determination of the fluence of contaminating photons. The measurements are usually carried out relative to reference cross sections which are reviewed in a separate contribution, but for certain conditions 'absolute' methods for neutron measurements can be used which are directly traceable to the international system of units (SI).

Ralf Nolte; David J Thomas

2011-01-01T23:59:59.000Z

245

Spallation Neutron Source | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutron Source SNS site, Spring 2012 The 80-acre SNS site is located on the east end of the ORNL campus and is about a three-minute drive from her sister neutron...

246

Science | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Science Neutron Science Neutron Scattering Science Neutrons are one of the fundamental particles that make up matter and have properties that make them ideal for certain types of research. In the universe, neutrons are abundant, making up more than half of all visible matter. Neutron scattering provides information about the positions, motions, and magnetic properties of solids. When a beam of neutrons is aimed at a sample, many neutrons will pass through the material. But some will interact directly with atomic nuclei and "bounce" away at an angle, like colliding balls in a game of pool. This behavior is called neutron diffraction, or neutron scattering. Using detectors, scientists can count scattered neutrons, measure their energies and the angles at which they scatter, and map their final position

247

Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE  

SciTech Connect

Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 35 eV and 200 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented, where the fission events were actively triggered during the experiments. In these experiments, the Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) from (n,f) events. The first evidence of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

Jandel, Marian [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

248

Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE  

SciTech Connect

Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 10 eV and 250 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented where the fission events were actively triggered during the experiments. In these experiments, a Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) events from (n,f) events. The first direct observation of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

Jandel, M.; Bredeweg, T. A.; Fowler, M. M.; Bond, E. M.; Couture, A.; Haight, R. C.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M. [Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Stoyer, M. A.; Wu, C. Y.; Becker, J. A.; Haslett, R. J.; Henderson, R. A. [Lawrence Livermore National Laboratory, Livermore, CA, 94550 (United States)

2009-01-28T23:59:59.000Z

249

Neutron lifetime measured with stored ultracold neutrons  

Science Journals Connector (OSTI)

The neutron lifetime has been measured by counting the neutrons remaining in a fluid-walled bottle as a function of the duration of storage. Losses of neutrons caused by the wall reflections are eliminated by varying the bottle volume-to-surface ratio. The result obtained is ??=887.6±3 s.

W. Mampe; P. Ageron; C. Bates; J. M. Pendlebury; A. Steyerl

1989-08-07T23:59:59.000Z

250

Neutron-Neutron Quasifree Scattering  

Science Journals Connector (OSTI)

The reaction D(n ,2n)p has been measured at Einc=14.1 MeV, ?n (3)=?n(4)=30?, ?=180?, and the results are compared with the predictions of two separable-potential models. Neutron-proton and proton-proton quasifree scattering from nucleon + deuteron reactions at 14 MeV are also compared with the predictions of the same models. The upper limit of 2 mb/sr2 is determined for the reaction D(n,n?)d.

Ivo Slaus; J. W. Sunier; G. Thompson; J. C. Young; J. W. Verba; D. J. Margaziotis; P. Doherty; R. T. Cahill

1971-03-29T23:59:59.000Z

251

Physics characteristics of a large, passive, pressure tube light water reactor with voided calandria  

SciTech Connect

A light water cooled and moderated pressure tube reactor concept has been developed that can survive loss-of-coolant accidents (LOCAs) without scram and without replenishing primary coolant inventory, while maintaining safe temperature limits on the fuel and pressure tube. The reactor employs a solid SiC-coated graphite fuel matrix in the pressure tubes and a calandria tank containing a low-pressure gas, surrounded by a graphite reflector. This normally voided calandria is connected to a light water heat sink. The cover gas displaces light water from the calandria during normal operation, while during LOCAs it allows passive calandria flooding. It is shown that such a system, with high void fraction in the core region, exhibits a high degree of neutron thermalization and a large prompt neutron lifetime, similar to D{sub 2}O moderated cores, although light water is used as both coolant and moderator. Moreover, the extremely large neutron migration length results in a strongly coupled core with a flat thermal flux profile and inherent stability against xenon spatial oscillations. The heterogeneous arrangement of the fuel and moderator ensures a negative void coefficient under all circumstances. Flooding of the calandria space with light water results in redundant reactor shutdown. Use of particle fuel allows attainment of high burnups.

Hejzlar, P.; Driscoll, M.J.; Todreas, N.E. [Massachusetts Inst. of Technology, Cambridge, MA (United States). Dept. of Nuclear Engineering

1995-11-01T23:59:59.000Z

252

Methodology for the use of proportional counters in pulsed fast neutron yield measurements  

E-Print Network (OSTI)

This paper introduces in full detail a methodology for the measurement of neutron yield and the necessary efficiency calibration, to be applied to the intensity measurement of neutron bursts where individual neutrons are not resolved in time, for any given moderated neutron proportional counter array. The method allows efficiency calibration employing the detection neutrons arising from an isotopic neutron source. Full statistical study of the procedure is descripted, taking into account contributions arising from counting statistics, piling-up statistics of real detector pulse-height spectra and background fluctuations. The useful information is extracted from the net waveform area of the signal arising from the electric charge accumulated inside the detector tube. Improvement of detection limit is gained, therefore this detection system can be used in detection of low emission neutron pulsed sources with pulses of duration from nanoseconds to up. The application of the methodology to detection systems to be...

Tarifeño-Saldivia, Ariel; Pavez, Cristian; Soto, Leopoldo

2011-01-01T23:59:59.000Z

253

WAND: Wide-Angle Neutron Diffractometer at HFIR | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

US/Japan Wide-Angle Neutron Diffractometer US/Japan Wide-Angle Neutron Diffractometer WAND Instrument scientist Jaime Fernandez-Baca (left) with a visiting researcher at WAND. The Wide-Angle Neutron Diffractometer (WAND) at the HFIR HB-2C beam tube was designed to provide two specialized data-collection capabilities: (1) fast measurements of medium-resolution powder-diffraction patterns and (2) measurements of diffuse scattering in single crystals using flat-cone geometry. For these purposes, this instrument is equipped with a curved, one-dimensional 3He position-sensitive detector covering 125º of the scattering angle with the focal distance of 71 cm. The sample and detector can be tilted in the flat-cone geometry mode. These features enable measurement of single-crystal diffraction patterns in a short time over a

254

Monte Carlo modeling of spallation targets containing uranium and americium  

E-Print Network (OSTI)

Neutron production and transport in spallation targets made of uranium and americium are studied with a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems). A good agreement of MCADS results with experimental data on neutron- and proton-induced reactions on $^{241}$Am and $^{243}$Am nuclei allows to use this model for simulations with extended Am targets. Several geometry options and material compositions (U, U+Am, Am, Am$_2$O$_3$) are considered for spallation targets to be used in Accelerator Driven Systems. It was demonstrated that MCADS model can be reliably used for calculating critical masses of fissile materials. All considered options operate as deep subcritical targets having neutron multiplication factor of $k \\sim 0.5$. It is found that more than 4 kg of Am can be burned in one spallation target during the first year of operation.

Malyshkin, Yury; Mishustin, Igor; Greiner, Walter

2013-01-01T23:59:59.000Z

255

Monte Carlo modeling of spallation targets containing uranium and americium  

E-Print Network (OSTI)

Neutron production and transport in spallation targets made of uranium and americium are studied with a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems). A good agreement of MCADS results with experimental data on neutron- and proton-induced reactions on $^{241}$Am and $^{243}$Am nuclei allows to use this model for simulations with extended Am targets. It was demonstrated that MCADS model can be used for calculating the values of critical mass for $^{233,235}$U, $^{237}$Np, $^{239}$Pu and $^{241}$Am. Several geometry options and material compositions (U, U+Am, Am, Am$_2$O$_3$) are considered for spallation targets to be used in Accelerator Driven Systems. All considered options operate as deep subcritical targets having neutron multiplication factor of $k \\sim 0.5$. It is found that more than 4 kg of Am can be burned in one spallation target during the first year of operation.

Yury Malyshkin; Igor Pshenichnov; Igor Mishustin; Walter Greiner

2014-05-02T23:59:59.000Z

256

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

257

Direct Measurement of Neutron?Neutron Scattering  

Science Journals Connector (OSTI)

In order to resolve long?standing discrepancies in indirect measurements of the neutron?neutron scattering length ann and contribute to solving the problem of the charge symmetry of the nuclear force the collaboration DIANNA (Direct Investigation of ann Association) plans to measure the neutron?neutron scattering cross section ? nn . The key issue of our approach is the use of the through?channel in the Russia reactor YAGUAR with a peak neutron flux of 1018 /cm2/s. The proposed experimental setup is described. Results of calculations are presented to connect ? nn with the nn?collision detector count rate and the neutron flux density in the reactor channel. Measurements of the thermal neutron fields inside polyethylene converters show excellent prospects for the realization of the direct nn?experiment.

E. I. Sharapov; C. D. Bowman; B. E. Crawford; W. I. Furman; C. R. Howell; B. G. Levakov; V. I. Litvin; W. I. Lychagin; A. E. Lyzhin; E. P. Magda; G. E. Mitchell; G. V. Muzichka; G. V. Nekhaev; Yu. V. Safronov; V. N. Shvetsov; S. L. Stephenson; A. V. Strelkov; W. Tornow

2003-01-01T23:59:59.000Z

258

Neutron-Mirror-Neutron Oscillations in a Trap  

E-Print Network (OSTI)

We calculate the rate of neutron-mirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov; O. Lychkovskiy

2008-04-03T23:59:59.000Z

259

Neutron–mirror-neutron oscillations in a trap  

Science Journals Connector (OSTI)

We calculate the rate of neutron–mirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov and O. Lychkovskiy

2008-06-27T23:59:59.000Z

260

Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron...  

NLE Websites -- All DOE Office Websites (Extended Search)

2013 LANSCE School on Neutron Scattering Geosciences & Materials in Extreme Environments Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron Science Center Los Alamos...

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

TARGETING TRICLOSAN  

Science Journals Connector (OSTI)

TARGETING TRICLOSAN ... FEDERAL REGULATORS are worried about the potential for antibiotic resistance and endocrine disruption from human exposure to triclosan, an antibacterial ingredient found in numerous consumer products, including soaps, body washes, cutting boards, and toys. ... “Existing data raise valid concerns about the effects of repetitive daily human exposure” to triclosan, the Food & Drug Administration wrote in a letter to Rep. Edward J. Markey (D-Mass.), which he released on April 8. ...

BRITT ERICKSON

2010-04-19T23:59:59.000Z

262

TABLE OF CONTENTS 2014 ORNL NEUTRON SCIENCES STRATEGIC PLAN  

NLE Websites -- All DOE Office Websites (Extended Search)

TABLE OF CONTENTS 2014 ORNL NEUTRON SCIENCES STRATEGIC PLAN Executive Summary Director's Message Introduction Neutron Scattering User Facilities Comparison with Leading International Neutron Facilities Strategic Planning and Research Community Involvement New Opportunities Science Priorities Introduction Quantum Materials Materials Synthesis and Performance Soft Molecular Matter Biosciences New and Upgraded Capabilities Enabling Technologies Sources Executing the Plan Strategic Timeline Appendices and Acronyms 3 6 17 55 43 51 59 9 3 EXECUTIVE SUMMARY 2014 ORNL NEUTRON SCIENCES STRATEGIC PLAN EXECUTIVE SUMMARY AND DIRECTOR'S MESSAGE * Optimizing existing instrumentation with targeted de-

263

Large Diameter Lasing Tube Cooling Arrangement  

DOE Patents (OSTI)

A cooling structure (16) for use inside a ceramic cylindrical tube (11) of a metal vapor laser (10) to cool the plasma in the tube (11), the cooling structure (16) comprising a plurality of circular metal members (17,31) and mounting members (18, 34) that position the metal members (17,31) coaxially in the tube (11) to form an annular lasing volume, with the metal members (17, 31) being axially spaced from each other along the length of the tube (11) to prevent the metal members from shorting out the current flow through the plasma in the tube (11) and to provide spaces through which the heat from localized hot spots in the plasma may radiate to the other side of the tube (11).

Hall, Jerome P.; Alger, Terry W.; Anderson, Andrew T.; Arnold, Philip A.

2004-05-18T23:59:59.000Z

264

Tube support grid and spacer therefor  

DOE Patents (OSTI)

A tube support grid and spacers therefor provide radially inward preloading of heat exchange tubes to minimize stress upon base welds due to differential thermal expansion. The grid comprises a concentric series of rings and spacers with opposing concave sides for conforming to the tubes and V-shaped ends to provide resilient flexibility. The flexibility aids in assembly and in transmitting seismic vibrations from the tubes to a shroud. The tube support grid may be assembled in place to achieve the desired inwardly radial preloading of the heat exchange tubes. Tab and slot assembly further minimizes stresses in the system. The radii of the grid rings may be preselected to effect the desired radially inward preloading.

Ringsmuth, Richard J. (Solano Beach, CA); Kaufman, Jay S. (Del Mar, CA)

1986-01-01T23:59:59.000Z

265

DEVELOPMENT OF HIGH TEMPERATURE TARGETS AND ION SOURCES FOR ONLINE RADIOACTIVE ISOTOPE PRODUCTION  

E-Print Network (OSTI)

and refractory metal carbide targets up to 2800--3000°K and up to 2500°K for uranium carbide targets. Tests of Ta refractory metal and refractory metal carbide targets 2.1. Off­line tests of a high temperature tantalum temperature uranium carbide targets of different density were carried out. High yields of Rb and Cs neutron

Titov, Anatoly

266

Sampling artifacts from conductive silicone tubing  

NLE Websites -- All DOE Office Websites (Extended Search)

Sampling artifacts from conductive silicone tubing Sampling artifacts from conductive silicone tubing Title Sampling artifacts from conductive silicone tubing Publication Type Journal Article Year of Publication 2009 Authors Timko, Michael T., Zhenhong Yu, Jesse Kroll, John T. Jayne, Douglas R. Worsnop, Richard C. Miake-Lye, Timothy B. Onasch, David Liscinsky, Thomas W. Kirchstetter, Hugo Destaillats, Amara L. Holder, Jared D. Smith, and Kevin R. Wilson Journal Aerosol Science and Technology Volume 43 Issue 9 Pagination 855-865 Date Published 06/03/2009 Abstract We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: (1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and (2) silicone tubing emits organic contaminants containing siloxane that are adsorbed onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and the tubing should, therefore, be used with caution. Contamination associated with the use of silicone tubing was observed at ambient temperature and, in some cases, was enhanced by mild heating (<70°C) or pre-exposure to a solvent (methanol). Further evaluation is warranted to quantify systematically how the contamination responds to variations in system temperature, physicochemical particle properties, exposure to solvent, sample contact time, tubing age, and sample flow rates.

267

Neutron crystallography aids drug design  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron crystallography aids drug design Neutron crystallography aids drug design Researchers have used neutron crystallography for the first time to determine the structure of a...

268

Los Alamos Neutron Science Center  

NLE Websites -- All DOE Office Websites (Extended Search)

LINAC Outreach Affiliations Visiting LANSCE Facilities Isotope Production Facility Lujan Neutron Scattering Center MaRIE Proton Radiography Ultracold Neutrons Weapons Neutron...

269

Optimizing Moderator Dimensions for Neutron Scattering at the Spallation Neutron Source  

SciTech Connect

In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source. In a recent study of the planned second target station at the Spallation Neutron Source (SNS) facility [1,2], we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter for a smaller viewing area [4]. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories, those with natural collimation and those that use neutron guide systems. We found that the cross-sections of the sample and the neutron guide, respectively, are the deciding factors for choosing the moderator. Beam divergence plays no role as long as it is within the reach of practical constraints. Namely, the required divergence is not too large for the guide or sample to be located close enough to the moderator on an actual spallation source.

Zhao, Jinkui [ORNL] [ORNL; Robertson, Lee [ORNL] [ORNL; Herwig, Kenneth W [ORNL] [ORNL; Gallmeier, Franz X [ORNL] [ORNL; Riemer, Bernie [ORNL] [ORNL

2013-01-01T23:59:59.000Z

270

Accelerator target  

DOE Patents (OSTI)

A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression. 5 figs.

Schlyer, D.J.; Ferrieri, R.A.; Koehler, C.

1999-06-29T23:59:59.000Z

271

Neutron range spectrometer  

DOE Patents (OSTI)

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

Manglos, Stephen H. (East Syracuse, NY)

1989-06-06T23:59:59.000Z

272

Neutron Generator as a Neutron Source for BNCT  

Science Journals Connector (OSTI)

A neutron generator was investigated for a neutron source for BNCT. Neutron generators have some obvious advantages over nuclear reactors for this purpose. The neutron source is the reaction D(d,n)3He. Moderation...

Gad Shani; Lev Tsvang; Semion Rozin; Michael Quastel

1996-01-01T23:59:59.000Z

273

Leakage-flow-induced vibration of a tube-in-tube slip joint. [LMFBR  

SciTech Connect

The susceptibility of a cantilevered tube conveying water to self-excitation by leakage flow through a slip joint is assessed experimentally. The slip joint is formed by inserting a smaller, rigid tube into the free end of the cantilevered tube. Variations of the slip joint annular gaps and engagement lengths are tested, and several mechanisms for self-excitation are described.

Mulcahy, T.M.

1983-06-01T23:59:59.000Z

274

Moderators - Instrument Support | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Moderators Moderators Detailed design of scattering instruments requires detailed knowledge of the neutron beam emitted from the moderator in question. We are currently providing moderator performance estimates based on the result of detailed Monte Carlo simulations of the entire target system. These simulations are being performed for both the High Power Target Station (HPTS) and the Long Wavelength Target Station (LWTS), and have been performed for the Intense Pulsed Neutron Source (IPNS) in the same manner. We make the IPNS source files available as a means to benchmark instrument simulation codes. These files follow a particular "source file format" which will adapt to the changing needs of instrument simulation as necessary. We also provide worked examples showing how to use the information in the source files

275

Fracture and tensile properties of irradiated zircaloy-2 pressure tubes  

SciTech Connect

The mechanical properties of nuclear reactor components degrade as a result of long service exposure in high-temperature, irradiation, and corrosive environments. Fracture toughness and tensile testing are conducted on the pressure tubes of Zircaloy-2 to evaluate the effects of neutron fluence, hydrogen content, and temperature on the mechanical properties. Tensile tests are performed on the base metal, and fracture toughness tests are performed on both the base and weld metals. Neutron irradiation increases the strength, reduces ductility, and significantly degrades fracture toughness. The postirradiation fracture toughness increases substantially as the test temperature is increased from room temperature to 250 C. Hydrogen levels up to 250 ppm are found to have little or no effect on the postirradiation fracture toughness. Because of its anisotropic nature, Zircaloy-2 displays different fracture resistances, depending on crack orientation. In the base metal, the fracture toughness in the longitudinal orientation is higher than that for the circumferential orientation, and this difference is enhanced at higher temperatures. The weld exhibits lower toughness in the longitudinal direction.

Huang, F.H.; Mills, W.J. (Westinghouse Hanford Co., Richland, WA (United States))

1993-06-01T23:59:59.000Z

276

Characterization of stainless steel 304 tubing  

SciTech Connect

Earlier studies have shown that stainless steel 304 (SS304) containing martensite is susceptible to hydrogen embrittlement. This generated concern regarding the structural integrity of SS304 tubing we use in the W87 pit tube. During surveillance operations, the pit tube undergoes a series of bending and straightening as it goes through a number of surveillance cycles. This motivated the study to characterize austenitic SS304 tubing obtained from Rocky Flats. The tubes continued to display structural soundness even after numerous repeated bending and straightening cycles. The minimum and maximum number of bends to failure occurred after 13 and 16 cycles, respectively. After 5 bends, both the inner and outer surfaces of the tubing showed no microcracks. When the bent tubing samples were pressurized and tested using deuterium at 74{degrees}C and at {approximately}78{degrees}C, they failed away from the bent area. Thus deuterium embrittlement of the bent SS304 tubing should not be a problem. Moreover, to increase our 95% confidence level to 5 bends, we are planning to perform at least four additional bends to failure tests.

Sunwoo, A.J.; Brooks, M.A.; Kervin, J.E.

1995-10-16T23:59:59.000Z

277

Sampling Artifacts from Conductive Silicone Tubing  

SciTech Connect

We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: 1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and 2) silicone tubing emits organic contaminants containing siloxane that adsorb onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and should, therefore, be used with caution. Gentle heating, physical and chemical properties of the particle carriers, exposure to solvents, and tubing age may influence siloxane uptake. The amount of contamination is expected to increase as the tubing surface area increases and as the particle surface area increases. The effect is observed at ambient temperature and enhanced by mild heating (<100 oC). Further evaluation is warranted.

Timko, Michael T.; Yu, Zhenhong; Kroll, Jesse; Jayne, John T.; Worsnop, Douglas R.; Miake-Lye, Richard C.; Onasch, Timothy B.; Liscinsky, David; Kirchstetter, Thomas W.; Destaillats, Hugo; Holder, Amara L.; Smith, Jared D.; Wilson, Kevin R.

2009-05-15T23:59:59.000Z

278

Dependence of projectile fragmentation on target N/Z  

Science Journals Connector (OSTI)

Peripheral reactions of 28Si with 112Sn and 124Sn at 30, 40, and 50 MeV/nucleon were used to elucidate the effect of the neutron content of the target on the process of projectile fragmentation. It is demonstrated that the fragments that result from these projectile fragmentation reactions can be divided into those which are the result of statistical emission of the quasiprojectile and those that are part of a direct component. The statistical part is independent of the target whereas the isotopic composition of fragments from the direct component is dependent on the neutron content of the target.

R. Laforest; E. Ramakrishnan; D. J. Rowland; A. Ruangma; E. M. Winchester; E. Martin; S. J. Yennello

1999-05-01T23:59:59.000Z

279

Neutron scattering on deformed nuclei  

Science Journals Connector (OSTI)

Measurements of neutron elastic and inelastic differential cross sections around 14 MeV for 9Be C 181 Ta 232Th 238U and 239Pu have been analyzed using a coupled channel (CC) formalism for deformed nuclei and phenomenological global optical model potentials (OMP). For the actinide targets these results are compared with the predictions of a semi?microscopic calculation using Jeukenne Lejeune and Mahaux (JLM) microscopic OMP and a deformed ground state nuclear density. The overall agreement between calculations and the measurements is reasonably good even for the very light nuclei where the quality of the fits is better than those obtained with spherical OMP.

L. F. Hansen; R. C. Haight; B. A. Pohl; C. Wong; Ch. Lagrange

1985-01-01T23:59:59.000Z

280

Target Diagnostics Supports NIF's Path to Ignition  

SciTech Connect

The physics requirements derived from the National Ignition Facility (NIF) experimental campaigns are leading to a wide variety of target diagnostics. Software development for the control and analysis of these diagnostics is included in the NIF Integrated Computer Control System, Diagnostic Control System and Data Visualization. These projects implement the configuration, controls, data analysis and visual representation of most of these diagnostics. To date, over 40 target diagnostics have been developed to support NIF experiments. In 2011 diagnostics were developed or enhanced to measure Ignition performance in a high neutron yield environment. Performance is optimized around four key variables: Adiabat (a) which is the strength and timing of four shocks delivered to the target, Velocity (V) of the imploding target, Mix (M) is the uniformity of the burn, and the Shape (S) of the imploding Deuterium Tritium (DT) hot spot. The diagnostics used to measure each of these parameters is shown in figure 1. Adiabat is measured using the Velocity Interferometer System for Any Reflector (VISAR) diagnostic consisting of three streak cameras. To provide for more accurate adiabat measurements the VISAR streak cameras were enhanced in FY11 with a ten comb fiducial signal controller to allow for post shot correction of the streak camera sweep non-linearity. Mix is measured by the Neutron Time of Flight (NTOF) and Radiochemical Analysis of Gaseous Samples (RAGS) diagnostics. To accommodate high neutron yield shots, NTOF diagnostic controls are being modified to use Mach Zehnder interferometer signals to allow the digitizers to be moved from near the target chamber to the neutron shielded diagnostic mezzanine. In December 2011 the first phase of RAGS diagnostic commissioning will be completed. This diagnostic will analyze the tracers that are added to NIF target capsules that undergo nuclear reactions during the shot. These gases are collected and purified for nuclear counting by the RAGS system. Three new instrument controllers were developed and commissioned to support this diagnostic. A residual-gas analyzer (RGA) instrument measures the gas content at various points in the system. The Digital Gamma Spectrometer instrument measures the radiological spectrum of the decaying gas isotopes. A final instrument controller was developed to interface to a PLC based Gas collection system. In order to support the implosion velocity measurements an additional Gated X-ray Detector (GXD) diagnostic was tested and commissioned. This third GXD views the target through a slit contained in its snout and allows the other GXD diagnostics to be used for measuring the shape on the same shot. In order to measure the implosion shape in a high neutron environment, Actide Readout In A Neutron Environment (ARIANE) and Neutron Imaging (NI) diagnostics were commissioned. The controls for ARIANE, a fixed port gated x-ray imager, contain a neutron shielded camera and micro channel plate pulser with its neutron sensitive electronics located in the diagnostic mezzanine. The NI diagnostic is composed of two Spectral Instruments SI-1000 cameras located 20M from the target and provides neutron images of the DT hot spot for high yield shots. The development and commissioning of these new or enhanced diagnostics in FY11 have provided meaningful insight that facilitates the optimization of the four key Ignition variables. In FY12 they will be adding three new diagnostics and enhancing four existing diagnostics in support of the continuing optimization series of campaigns.

Shelton, R

2011-12-07T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

A neutron multiplicity meter for deep underground muon-induced high-energy neutron measurements  

Science Journals Connector (OSTI)

We present, for the first time, the design of an instrument capable of measuring the high energy ( > 60 MeV ) muon-induced neutron flux deep underground. The instrument is based on applying the Gd-loaded liquid-scintillator technique to measure the rate of multiple low-energy neutron events produced in a Pb target and from this measurement to infer the rate of high energy neutron events. This unique signature allows both for efficient tagging of neutron multiplicity events as well as rejection of random gamma backgrounds so effectively that typical low-background techniques are not required. We present design studies based on Monte Carlo simulations that show that an apparatus consisting of a Pb target of 200 cm by 200 cm area by 60 cm thickness covered by a 60 cm thick Gd-loaded liquid scintillator (0.5% Gd content) detector could measure, at a depth of 2000 meters of water equivalent (m.w.e), a rate of 70 ± 8 (stat) events/year with a background of less than 10 events/year. We discuss the relevance of this technique to measuring the muon-induced neutron background in searches for dark matter in the form of Weakly Interacting Massive Particles (WIMP). Based on these studies, we also discuss the benefits of using a neutron multiplicity meter as a component of active shielding in such experiments.

R. Hennings-Yeomans; D.S. Akerib

2007-01-01T23:59:59.000Z

282

Ultracold-neutron production in a pulsed-neutron beam line  

Science Journals Connector (OSTI)

We present the results of an ultracold neutron (UCN) production experiment in a pulsed-neutron beam line at the Los Alamos Neutron Scattering Center. The experimental apparatus allows for a comprehensive set of measurements of UCN production as a function of target temperature, incident neutron energy, target volume, and applied magnetic field. However, the low counting statistics of the UCN signal can be overwhelmed by the large background associated with the scattering of the primary cold-neutron flux that is required for UCN production. We have developed a background subtraction technique that takes advantage of the very different time-of-flight profiles between the UCN and the cold neutrons, in the pulsed beam. Using the unique timing structure, we can reliably extract the UCN signal. Solid ortho-H22 is used to calibrate UCN transmission through the apparatus, which is designed primarily for studies of UCN production in solid O2. In addition to setting the overall detection efficiency in the apparatus, UCN production data using solid H22 suggest that the UCN upscattering cross section is smaller than previous estimates, indicating the deficiency of the incoherent approximation widely used to estimate inelastic cross sections in the thermal and cold regimes.

C. M. Lavelle; C.-Y. Liu; W. Fox; G. Manus; P. M. McChesney; D. J. Salvat; Y. Shin; M. Makela; C. Morris; A. Saunders; A. Couture; A. R. Young

2010-07-19T23:59:59.000Z

283

A study on the optimum fast neutron flux for Boron Neutron Capture Therapy of deep-seated tumors  

Science Journals Connector (OSTI)

Abstract High-energy neutrons, named fast neutrons which have a number of undesirable biological effects on tissue, are a challenging problem in beam designing for Boron Neutron Capture Therapy, BNCT. In spite of this fact, there is not a widely accepted criterion to guide the beam designer to determine the appropriate contribution of fast neutrons in the spectrum. Although a number of researchers have proposed a target value for the ratio of fast neutron flux to epithermal neutron flux, it can be shown that this criterion may not provide the optimum treatment condition. This simulation study deals with the determination of the optimum contribution of fast neutron flux in the beam for BNCT of deep-seated tumors. Since the dose due to these high-energy neutrons damages shallow tissues, delivered dose to skin is considered as a measure for determining the acceptability of the designed beam. To serve this purpose, various beam shaping assemblies that result in different contribution of fast neutron flux are designed. The performances of the neutron beams corresponding to such configurations are assessed in a simulated head phantom. It is shown that the previously used criterion, which suggests a limit value for the contribution of fast neutrons in beam, does not necessarily provide the optimum condition. Accordingly, it is important to specify other complementary limits considering the energy of fast neutrons. By analyzing various neutron spectra, two limits on fast neutron flux are proposed and their validity is investigated. The results show that considering these limits together with the widely accepted IAEA criteria makes it possible to have a more realistic assessment of sufficiency of the designed beam. Satisfying these criteria not only leads to reduction of delivered dose to skin, but also increases the advantage depth in tissue and delivered dose to tumor during the treatment time. The Monte Carlo Code, MCNP-X, is used to perform these simulations.

Fatemeh S. Rasouli; S. Farhad Masoudi

2015-01-01T23:59:59.000Z

284

Pulsed D-D Neutron Generator Measurements of HEU Oxide Fuel Pins  

SciTech Connect

Pulsed neutron interrogation measurements have been performed on highly enriched uranium (HEU) oxide fuel pins and depleted uranium (DU) metal using a D-D neutron generator (2x10{sup 6} neutrons-s{sup -1}) and moderated {sup 3}He tubes at the Idaho National Laboratory Power Burst Facility. These measurements demonstrate the ability to distinguish HEU from DU by coincidence counting using a pulsed source. The amount of HEU measured was 8 kg in a sealed 55-gallon drum compared to 31 kg of DU. Neutron events were counted during and after the pulse with the Nuclear Materials Identification System (NMIS) and used to calculate the neutron coincidence time distributions. Passive measurements were also performed for comparison with the pulsed measurements. This paper presents the neutron coincidence time distribution and Feynman variance results from the measurements.

McConchie, Seth; Hausladen, Paul; Mihalczo, John [Oak Ridge National Laboratory, 1 Bethel Valley Road, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Blackburn, Brandon; Chichester, David [Idaho National Laboratory, 2525 North Fremont Avenue, P.O. Box 1625, Idaho Falls, ID 83415 (United States)

2009-03-10T23:59:59.000Z

285

Pulsed D-D Neutron Generator Measurements of HEU Oxide Fuel Pins  

SciTech Connect

Pulsed neutron interrogation measurements have been performed on highly enriched uranium (HEU) oxide fuel pins and depleted uranium (DU) metal using a D-D neutron generator (2 x 10{sup 6} neutrons-s{sup -1}) and moderated {sup 3}He tubes at the Idaho National Laboratory Power Burst Facility. These measurements demonstrate the ability to distinguish HEU from DU by coincidence counting using a pulsed source. The amount of HEU measured was 8 kg in a sealed 55-gallon drum compared to 31 kg of DU. Neutron events were counted during and after the pulse with the Nuclear Materials Identification System (NMIS) and used to calculate the neutron coincidence time distributions. Passive measurements were also performed for comparison with the pulsed measurements. This paper presents the neutron coincidence distribution and Feynman variance results from the measurements.

McConchie, Seth M [ORNL] [ORNL; Hausladen, Paul [ORNL] [ORNL; Mihalczo, John T [ORNL] [ORNL; Blackburn, Brandon [Idaho National Laboratory (INL)] [Idaho National Laboratory (INL); Chichester, David [Idaho National Laboratory (INL)] [Idaho National Laboratory (INL)

2009-01-01T23:59:59.000Z

286

Instruments | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

NScD Careers NScD Careers Supporting Organizations Neutron Science Home | Science & Discovery | Neutron Science | Instruments SHARE Instruments at SNS and HFIR SNS Instrument Name HFIR Instrument Name 1B NOMAD - Nanoscale-Ordered Materials Diffractometer CG-1 Development Beam Line 2 BASIS - Backscattering Spectrometer CG-1D IMAGING - Neutron Imaging Prototype Facility 3 SNAP - Spallation Neutrons and Pressure Diffractometer CG-2 GP-SANS - General-Purpose Small-Angle Neutron Scattering Diffractometer 4A MR - Magnetism Reflectometer CG-3 Bio-SANS - Biological Small-Angle Neutron Scattering Instrument 4B LR - Liquids Reflectometer CG-4C CTAX - Cold Neutron Triple-Axis Spectrometer 5 CNCS - Cold Neutron Chopper Spectrometer HB-1 PTAX - Polarized Triple-Axis Spectrometer

287

The Harwell Neutron Project  

Science Journals Connector (OSTI)

... 2 cm. thick, placed on three sides of the neutron booster. A layer of boron-10 metal placed between these tanks and the uranium-235 core prevents return of slow neutrons ...

M. J. POOLE; E. R. RAE

1960-01-30T23:59:59.000Z

288

Neutrons - 88-Inch Cyclotron  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutrons Neutron beams are available at the 88-Inch Cyclotron. Available energies range of from 8 to 30 MeV, with fluxes of up to 1E8 neutronscm2sec. For more information,...

289

Thermal Neutron Scattering  

Science Journals Connector (OSTI)

... of its title. It is not for the nuclear physicist, nor even for the neutron physicist, but for the student of solids and liquids. "Thermal ... physicist, but for the student of solids and liquids. "Thermal neutron ...

G. E. BACON

1968-11-09T23:59:59.000Z

290

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis (NAA) is an that relies on the measurement of ?-rays emitted from a sample that was irradiated by neutrons. The rate at which ?-rays are emitted from an element in a sample is dir...

James R. Budahn

1998-01-01T23:59:59.000Z

291

Ultrafast neutron detector  

DOE Patents (OSTI)

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Wang, C.L.

1985-06-19T23:59:59.000Z

292

Development of a new deuterium–deuterium (D–D) neutron generator for prompt gamma-ray neutron activation analysis  

Science Journals Connector (OSTI)

Abstract A new deuterium–deuterium (D–D) neutron generator has been developed by Adelphi Technology for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA), and fast neutron radiography. The generator makes an excellent fast, intermediate, and thermal neutron source for laboratories and industrial applications that require the safe production of neutrons, a small footprint, low cost, and small regulatory burden. The generator has three major components: a Radio Frequency Induction Ion Source, a Secondary Electron Shroud, and a Diode Accelerator Structure and Target. Monoenergetic neutrons (2.5 MeV) are produced with a yield of 1010 n/s using 25–50 mA of deuterium ion beam current and 125 kV of acceleration voltage. The present study characterizes the performance of the neutron generator with respect to neutron yield, neutron production efficiency, and the ionic current as a function of the acceleration voltage at various RF powers. In addition the Monte Carlo N-Particle Transport (MCNP) simulation code was used to optimize the setup with respect to thermal flux and radiation protection.

K. Bergaoui; N. Reguigui; C.K. Gary; C. Brown; J.T. Cremer; J.H. Vainionpaa; M.A. Piestrup

2014-01-01T23:59:59.000Z

293

Neutron computed tomography  

E-Print Network (OSTI)

to make the Donner Algorithms run. TABLE OF CONTEliiTS CHAPTF. . R I NEI. TRON RADIOGRAPHY . I. 1 Background . I. 2 Theory . l. 3 Neutron Beam Characterization I. 4 Image Detectors . COMPI'TED TOMOGRAPHY . Il I Background . II. 2 Notation II. 3... data which is generated by rays traveling (and being attenuated) in straight lines. However in neutron radiography, what is measured is, to most extents, the levels of neutrons which are not attenuated. Neutrons are particles. They scatter...

Russell, Clifford Marlow

2012-06-07T23:59:59.000Z

294

Neutron scattering and ribosomes  

Science Journals Connector (OSTI)

... the complexity of intra-ribosomal interactions. This is however by no means the case with neutron ...neutronscattering ...

Richard Brimacombe

1977-06-23T23:59:59.000Z

295

Method and apparatus for optimized sampling of volatilizable target substances  

DOE Patents (OSTI)

An apparatus for capturing, from gases such as soil gas, target analytes. Target analytes may include emanations from explosive materials or from residues of explosive materials. The apparatus employs principles of sorption common to solid phase microextraction, and is best used in conjunction with analysis means such as a gas chromatograph. To sorb target analytes, the apparatus functions using various sorptive structures to capture target analyte. Depending upon the embodiment, those structures may include 1) a conventional solid-phase microextraction (SPME) fiber, 2) a SPME fiber suspended in a capillary tube (with means provided for moving gases through the capillary tube so that the gases come into close proximity to the suspended fiber), and 3) a capillary tube including an interior surface on which sorptive material (similar to that on the surface of a SPME fiber) is supported (along with means for moving gases through the capillary tube so that the gases come into close proximity to the sorptive material). In one disclosed embodiment, at least one such sorptive structure is associated with an enclosure including an opening in communication with the surface of a soil region potentially contaminated with buried explosive material such as unexploded ordnance. Emanations from explosive materials can pass into and accumulate in the enclosure where they are sorbed by the sorptive structures. Also disclosed is the use of heating means such as microwave horns to drive target analytes into the soil gas from solid and liquid phase components of the soil.

Lindgren, Eric R. (Albuquerque, NM); Phelan, James M. (Bosque Farms, NM)

2002-01-01T23:59:59.000Z

296

More about neutron - mirror neutron oscillation  

E-Print Network (OSTI)

It was pointed out recently that oscillation of the neutron $n$ into mirror neutron $n'$, a sterile twin of the neutron with exactly the same mass, could be a very fast process with the the baryon number violation, even faster than the neutron decay itself. This process is sensitive to the magnetic fields and it could be observed by comparing the neutron lose rates in the UCN storage chambers for different magnetic backgrounds. We calculate the probability of $n-n'$ oscillation in the case when a mirror magnetic field $\\vec{B}'$ is non-zero and show that in this case it can be suppressed or resonantly enhanced by applying the ordinary magnetic field $\\vec{B}$, depending on its strength and on its orientation with respect to $\\vec{B}'$. The recent experimental data, under this hypothesis, still allow the $n-n'$ oscillation time order 1 s or even smaller. Moreover, they indicate that the neutron losses are sensitive to the orientation of the magnetic field. %at about $3\\sigma$ level. If these hints will be confirmed in the future experiments, this would point to the presence of the mirror magnetic field on the Earth of the order of 0.1 G, or some equivalent spin-dependent force of the other origin that makes a difference between the neutron and mirror neutron states.

Zurab Berezhiani

2008-04-13T23:59:59.000Z

297

Neutron removal cross section as a measure of neutron skin  

Science Journals Connector (OSTI)

We study the relation between neutron removal cross section (?-N) and neutron skin thickness for finite neutron-rich nuclei using the statistical abrasion ablation model. Different sizes of neutron skin are obtained by adjusting the diffuseness parameter of neutrons in the Fermi distribution. It is demonstrated that there is a good linear correlation between ?-N and the neutron skin thickness for neutron-rich nuclei. Further analysis suggests that the relative increase of neutron removal cross section could be used as a quantitative measure for neutron skin thickness in neutron-rich nuclei.

D. Q. Fang (???); Y. G. Ma (???); X. Z. Cai (???); W. D. Tian (???); H. W. Wang (???)

2010-04-07T23:59:59.000Z

298

The neutron warhead decision  

Science Journals Connector (OSTI)

The neutron warhead decision ... Nuclear war moved a step closer last week with the U.S.'s decision to move ahead with production of so-called neutron warheads for use on short-range missiles and in artillery shells. ... And neutron weapons would be almost as effective on ... ...

MICHAEL HEYLIN

1981-08-17T23:59:59.000Z

299

Optimizing moderator dimensions for neutron scattering at the spallation neutron source  

SciTech Connect

In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter)

Zhao, J. K.; Robertson, J. L.; Herwig, Kenneth W.; Gallmeier, Franz X.; Riemer, Bernard W. [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2013-12-15T23:59:59.000Z

300

Multi-tube fuel nozzle with mixing features  

DOE Patents (OSTI)

A system includes a multi-tube fuel nozzle having an inlet plate and a plurality of tubes adjacent the inlet plate. The inlet plate includes a plurality of apertures, and each aperture includes an inlet feature. Each tube of the plurality of tubes is coupled to an aperture of the plurality of apertures. The multi-tube fuel nozzle includes a differential configuration of inlet features among the plurality of tubes.

Hughes, Michael John

2014-04-22T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Progress with developing a target for magnetized target fusion  

SciTech Connect

Magnetized Target Fusion (MTF) is an approach to fusion where a preheated and magnetized plasma is adiabatically compressed to fusion conditions. Successful MTF requires a suitable initial target plasma with an embedded magnetic field of at least 5 T in a closed-field-line topology, a density of roughly 10{sup 18} cm{sup {minus}3}, a temperature of at least 50 eV, and must be free of impurities which would raise radiation losses. Target plasma generation experiments are underway at Los Alamos National Laboratory using the Colt facility; a 0.25 MJ, 2--3 {micro}s rise-time capacitor bank. The goal of these experiments is to demonstrate plasma conditions meeting the minimum requirements for a MTF initial target plasma. In the first experiments, a Z-pinch is produced in a 2 cm radius by 2 cm high conducting wall using a static gas-fill of hydrogen or deuterium gas in the range of 0.5 to 2 torr. Thus far, the diagnostics include an array of 12 B-dot probes, framing camera, gated OMA visible spectrometer, time-resolved monochrometer, filtered silicon photodiodes, neutron yield, and plasma-density interferometer. These diagnostics show that a plasma is produced in the containment region that lasts roughly 10 to 20 {micro}s with a maximum plasma density exceeding 10{sup 18} cm{sup {minus}3}. The experimental design and data are presented.

Wysocki, F.J.; Chrien, R.E.; Idzorek, G.; Oona, H.; Whiteson, D.O.; Kirkpatrick, R.C.; Lindemuth, I.R.; Sheehey, P.T.

1997-09-01T23:59:59.000Z

302

Detonation limits in rough walled tubes  

Science Journals Connector (OSTI)

Abstract The present paper reports the results of a study of detonation limits in rough tubes. Detonation velocity is measured by photodiodes and ionization probes spaced at 10 cm intervals along the length of the tube. Short lengths of smoked foils inserted into the core of the rough tube is used to register the structure of the detonation wave. Pressure transducers are also used to obtain the pressure profile. The results indicate that in rough tubes, the detonation velocity is generally much lower than the corresponding values for smooth tubes. The velocity decreases slowly at first and then more rapidly as the limit is approached. The velocity variation is generally continuous and at the limits, the failure velocity is of the order of about 0.4 V CJ for all cases. The detonation limits in rough tubes are found to be wider than for a smooth tube. This indicates that the turbulence generated by the wall roughness facilitates the propagation of the detonation and extends the limits. Smoked foil records show that in the core of the rough tube the detonation front has a cellular structure corresponding to the usual cellular structure due to instability of the detonation. Thus the intrinsic unstable cellular structure is quite robust and retains its global characteristics in spite of the large perturbations generated by the rough wall. The detonation in the core of the rough tube goes from multi-headed to single headed as the limit is approached. Past the single headed spin, the low velocity detonation has no cellular structure but consists of interacting weak transverse waves from the rough wall. The averaged pressure of the low velocity detonation front corresponds to about the constant volume explosion pressure, in accord with the velocity of the low velocity detonation.

Amanda Starr; John H.S. Lee; Hoi Dick Ng

2014-01-01T23:59:59.000Z

303

Alternative Electrostatic Green's Function for a Long Tube. ...  

NLE Websites -- All DOE Office Websites (Extended Search)

Alternative Electrostatic Green's Function for a Long Tube. Alternative Electrostatic Green's Function for a Long Tube. Abstract: This note describes an expression for the...

304

Starter for inductively coupled plasma tube  

DOE Patents (OSTI)

A starter assembly is provided for use with an inductively coupled plasma (ICP) tube to reliably initiate a plasma at internal pressures above about 30 microns. A conductive probe is inserted within the inductor coil about the tube and insulated from the tube shield assembly. A capacitive circuit is arranged for momentarily connecting a high voltage radio-frequency generator to the probe while simultaneously energizing the coil. When the plasma is initiated the probe is disconnected from the generator and electrically connected to the shield assembly for operation. 1 fig.

Hull, D.E.; Bieniewski, T.M.

1988-08-23T23:59:59.000Z

305

High energy neutron dosimeter  

DOE Patents (OSTI)

A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures.

Rai, K.S.F.

1994-01-11T23:59:59.000Z

306

Principles of neutron reflection  

SciTech Connect

Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs.

Felcher, G.P.

1988-08-01T23:59:59.000Z

307

Uranium Neutron Coincidence Collar Model Utilizing 3He  

SciTech Connect

The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube based alternative system in a configuration typically used for 3He-based coincidence counter applications. The specific application selected for boron-lined tube replacement in this project was one of the Uranium Neutron Coincidence Collar (UNCL) designs. This report, providing results for model development of a UNCL, is a deliverable under Task 2 of the project. The current UNCL instruments utilize 3He tubes. As the first step in developing and optimizing a boron-lined proportional counter based version of the UNCL, models of eight different 3He-based UNCL detectors currently in use were developed and evaluated. A comparison was made between the simulated results and measured efficiencies for those systems with values reported in the literature. The reported experimental measurements for efficiencies and die-away times agree to within 10%.

Siciliano, Edward R.; Rogers, Jeremy L.; Schweppe, John E.; Lintereur, Azaree T.; Kouzes, Richard T.

2012-07-30T23:59:59.000Z

308

On neutron numbers and atomic masses  

Science Journals Connector (OSTI)

On neutron numbers and atomic masses ... Assigning neutron numbers, correct neutron numbers, and atomic masses and nucleon numbers. ...

R. Heyrovská

1992-01-01T23:59:59.000Z

309

Spallation Neutron Source, SNS  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutron Source Spallation Neutron Source Providing the most intense pulsed neutron beams in the world... Accumulator Ring Commissioning Latest Step for Spallation Neutron Source The Spallation Neutron Source, located at Oak Ridge National Laboratory, has passed another milestone on the way to completion this year--the commissioning of the proton accumulator ring. Brookhaven led the design and construction of the accumulator ring, which will allow an order of magnitude more beam power than any other facility in the world. The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The figure on the right shows a schematic of the accumulator ring and transport beam lines that are being designed and built by Brookhaven

310

The Neutron Lifetime  

E-Print Network (OSTI)

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

Wietfeldt, F E

2014-01-01T23:59:59.000Z

311

The Neutron Lifetime  

E-Print Network (OSTI)

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

F. E. Wietfeldt

2014-11-13T23:59:59.000Z

312

High Flux Isotope Reactor cold neutron source reference design concept  

SciTech Connect

In February 1995, Oak Ridge National Laboratory`s (ORNL`s) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH{sub 2}) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH{sub 2} cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept.

Selby, D.L.; Lucas, A.T.; Hyman, C.R. [and others

1998-05-01T23:59:59.000Z

313

Neutron production with mixture of deuterium and krypton in Sahand Filippov type plasma focus facility  

Science Journals Connector (OSTI)

This Letter reports the order of magnitude enhancement in neutron yield from Sahand plasma focus device with krypton seeded deuterium operation. The highest average neutron yield of 2.2 × 10 9 neutrons per shot was achieved at 1.00 Torr deuterium with 3% krypton which is higher than the best average neutron yield of 3.18 × 10 8 neutrons per shot for pure deuterium operation. Estimation of average neutron energy showed that the maximum and minimum average energies are 2.98 ± 0.6   MeV at 16 kV in 0.25 Torr deuterium with 3% Kr and 2.07 ± 0.2   MeV at 18 kV operation in 0.5 Torr deuterium with 3% Kr, respectively. The anisotropy of neutron emission from Sahand DPF showed that the neutrons are produced mainly by beam–target mechanisms.

M.A. Mohammadi; S. Sobhanian; R.S. Rawat

2011-01-01T23:59:59.000Z

314

Published Research 2012 | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

2 2 Most publications are in Adobe Portable Document Format. Download Adobe Reader. For more information about any of these publications, please contact the Neutrons Sciences Communications Office. Primary Author Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A Abdou A., Wendel M., Riemer B., Volpenheini E., Brewster R., "Two-phase flow simulations of protective gas layer for Spallation Neutron Source target", ASME International Mechanical Engineering Congress and Exposition 2011. Abernathy D. L., Stone M. B., Loguillo M. J., Lucas M. S., Delaire O., Tang X., Lin J. Y.Y., Fultz B., "Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source", Review of Scientific Instruments 83, 15114. Aczel A. A., Granroth G. E., MacDougall G. J., Buyers W. J.L.,

315

Precision Measurement of the n-3He Incoherent Scattering Length Using Neutron Interferometry  

E-Print Network (OSTI)

We report the first measurement of the low-energy neutron-$^3$He incoherent scattering length using neutron interferometry: $b_i' = (-2.512\\pm 0.012{statistical}\\pm0.014{systematic})$ fm. This is in good agreement with a recent calculation using the AV18+3N potential. The neutron-$^3$He scattering lengths are important for testing and developing nuclear potential models that include three nucleon forces, effective field theories for few-body nuclear systems, and neutron scattering measurements of quantum excitations in liquid helium. This work demonstrates the first use of a polarized nuclear target in a neutron interferometer.

M. G. Huber; M. Arif; T. C. Black; W. C. Chen; T. R. Gentile; D. S. Hussey; D. Pushin; F. E. Wietfeldt; L. Yang

2009-05-12T23:59:59.000Z

316

Frictional forces in helical buckling of tubing  

SciTech Connect

Previous analyses of helical buckling of tubing have not considered frictional forces. This paper describes the modifications to helical buckling theory necessary to include friction. The first need is a relationship between the buckling force and the casing to tubing contact force. This contact force is determined through use of the principle of virtual work. The next need is the relationship between the friction forces, the buckling force, and the geometry of the tubing helix. Differential equations are derived and solved for two cases of interest: buckling during the landing of the tubing and thermal and differential pressure loading subsequent to landing. Several example problems are examined to evaluate the relative importance of friction.

Mitchell, R.F.

1984-09-01T23:59:59.000Z

317

High-Pressure Tube Trailers and Tanks  

Energy.gov (U.S. Department of Energy (DOE))

Presentation on High-Pressure Tube Trailers and Tanks for the DOE Hydrogen Delivery High-Pressure Tanks and Analysis Project Review Meeting held February 8-9, 2005 at Argonne National Laboratory

318

Impedance tube measurements of printed porous materials  

Science Journals Connector (OSTI)

An impedance tube has been used to make measurements of the acoustic impedance of porous samples. Porous with designed porosities and tortuosities have been produced using 3D printing. Measured impedances are compared to calculated values.

Carl Frederickson

2014-01-01T23:59:59.000Z

319

Sample inlet tube for ion source  

DOE Patents (OSTI)

An improved inlet tube is positioned within an aperture through the device to allow the passage of ions from the ion source, through the improved inlet tube, and into the interior of the device. The inlet tube is designed with a larger end and a smaller end wherein the larger end has a larger interior diameter than the interior diameter of the smaller end. The inlet tube is positioned within the aperture such that the larger end is pointed towards the ion source, to receive ions therefrom, and the smaller end is directed towards the interior of the device, to deliver the ions thereto. Preferably, the ion source utilized in the operation of the present invention is a standard electrospray ionization source. Similarly, the present invention finds particular utility in conjunction with analytical devices such as mass spectrometers.

Prior, David [Hermiston, OR; Price, John [Richland, WA; Bruce, Jim [Oceanside, CA

2002-09-24T23:59:59.000Z

320

Magnetic field lines for a flux tube  

Science Journals Connector (OSTI)

Equations for the magnetic field components in a two dimensional cylindrically symmetric ... in a simple case, solved. The resulting magnetic configuration possesses a strong magnetic field in a thin tube below a...

C. D. C. Steele; Rekha Jain

1993-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Forced-convection condensation inside tubes  

E-Print Network (OSTI)

High vapor velocity condensation inside a tube was studied analytically. The von Karman universal velocity distribution was applied to the condensate flow, pressure drops were calculated using the Lockhart- Martinelli ...

Traviss, Donald P.

1971-01-01T23:59:59.000Z

322

Floor tube corrosion in recovery boilers  

SciTech Connect

Lower sulfur emissions at a pulp mill result in higher sulfidity levels and in the enrichment of potassium in the mill`s liquor system. The sulfidity values at Scandinavian kraft mills previously fluctuated between 28 and 35%; today they exceed 45%. Viscosity measurements show that the viscosity decreases drastically when the sulfidity increases from 30 mole% to 40 mole%, its potassium and chlorine levels are high enough, and the char bed is low, the smelt flows easily and may penetrate the char bed, approaching the floor tubes. In extreme cases, the hot smelt destroys the layer of solidified smelt on the floor tube`s surface and reacts very rapidly with the floor tube.

Klarin, A. [A. Ahistrom Corp., Helsinki (Finland)

1993-12-01T23:59:59.000Z

323

Imaging and Neutrons - IAN 2006 - Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

SNS Home Saturday, January 11, 2014 SNS Home Saturday, January 11, 2014 Go IAN 2006 Imaging and Neutrons 2006 October 23-25, 2006 Iran Thomas Auditorium Central Laboratory and Office Building Spallation Neutron Source Oak Ridge National Laboratory, Oak Ridge, TN Who Should Attend Synopsis Goals and Expected Outcomes Application Areas Techniques International Advisory Committee Local Organizing Committee Agenda with Presentations NEW Confirmed Speakers Frequently Asked Questions - FAQ Satellite Workshop - Progress in Electron Volt Neutron Spectroscopy eV Worshop Agenda presentations NEW Lodging, Transportation, Bus Schedule Location Directions and Map Registration CLOSED Abstracts, Posters, Contributed Talks Scholarships Sponsors Vendors May Attend Relevant Reports Important Dates Weather Attractions

324

Generalized correlation for foam flow in tubes  

E-Print Network (OSTI)

GENERALIZED CORRELATION FOR FOAM FLOW IN TUBES A Thesis by CAROL LYNNETTE COTTER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December.... (December 1996) Carol Lynnette Cotter, B. S. , Texas A&M University Chair of Advisory Committee: Dr. Raymond W. Flumerfelt A novel experimental procedure to determine the behavior of foam flow in tubes is established. Using an approach developed...

Cotter, Carol Lynnette

2012-06-07T23:59:59.000Z

325

Soft pion emission from fat flux tubes  

SciTech Connect

The emission of pions from multiquark flux tubes is examined as an explanation of the soft pion puzzle. Although the soft pion spectra from the decay of fat flux tubes can account for some low {ital p}{sub {perpendicular}} enhancement, the dependence on the number of involved quarks is too weak to provide a plausible explanation of the observed enhancement in the pion spectrum at low transverse momenta.

Kusnezov, D.; Danielewicz, P. (National Superconducting Cyclotron Laboratory and Department of Physics Astronomy, Michigan State University, East Lansing, Michigan (USA))

1991-08-01T23:59:59.000Z

326

Tube construction for fluidized bed combustor  

DOE Patents (OSTI)

A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

De Feo, Angelo (Totowa, NJ); Hosek, William (Mt. Tabor, NJ)

1984-01-01T23:59:59.000Z

327

Fluidized bed combustor and tube construction therefor  

DOE Patents (OSTI)

A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

De Feo, Angelo (Passaic, NJ); Hosek, William (Morris, NJ)

1981-01-01T23:59:59.000Z

328

Neutron production by cosmicray muons at shallow depth F. Boehm, 3 J. Busenitz, 1 B. Cook, 3 G. Gratta, 4 H. Henrikson, 3 J. Kornis, 1 D. Lawrence, 2 K. B. Lee, 3 K. McKinny, 1  

E-Print Network (OSTI)

Neutron production by cosmic­ray muons at shallow depth F. Boehm, 3 J. Busenitz, 1 B. Cook, 3 G, Stanford, California 94305 #Received 23 June 2000; published 12 October 2000# The yield of neutrons of acrylic, served as a target. The rate of one and two neutron captures was determined. Modeling the neutron

Gratta, Giorgio

329

New upper bound on the scattering cross section of slow neutrons on liquid parahydrogen from neutron transmission  

E-Print Network (OSTI)

The scattering of slow neutron beams provides unique, non-destructive, quantitative information on the structure and dynamics of materials of interest in physics, chemistry, materials science, biology, geology, and other fields. Liquid hydrogen is a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. In particular the rapid drop of the slow neutron scattering cross section of liquid parahydrogen below 15 meV, which renders the moderator volume transparent to the neutron energies of most interest for scattering studies, is therefore especially interesting and important. We have placed an upper bound on the total cross section and the scattering cross section for slow neutrons with energies between 0.43 meV and 16.1 meV on liquid hydrogen at 15.6 K using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge Nati...

Grammer, K B; Barrón-Palos, L; Blyth, D; Bowman, J D; Calarco, J; Crawford, C; Craycraft, K; Evans, D; Fomin, N; Fry, J; Gericke, M; Gillis, R C; Greene, G L; Hamblen, J; Hayes, C; Kucuker, S; Mahurin, R; Maldonado-Velázquez, M; Martin, E; McCrea, M; Mueller, P E; Musgrave, M; Nann, H; Penttilä, S I; Snow, W M; Tang, Z; Wilburn, W S

2014-01-01T23:59:59.000Z

330

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents (OSTI)

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

1997-03-18T23:59:59.000Z

331

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents (OSTI)

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

Miura, M.; Slatkin, D.N.

1997-03-18T23:59:59.000Z

332

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents (OSTI)

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

1995-10-03T23:59:59.000Z

333

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents (OSTI)

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

Miura, M.; Slatkin, D.N.

1997-08-05T23:59:59.000Z

334

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents (OSTI)

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized. by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

1997-08-05T23:59:59.000Z

335

Cold neutron research facility at the Budapest Neutron Centre  

Science Journals Connector (OSTI)

The new cold neutron research facility has been routinely operated at the Budapest Neutron Centre (BNC) since February 2001. This ... of equipment consists of a liquid hydrogen cold neutron source, an optimised s...

L. Rosta

2002-12-01T23:59:59.000Z

336

Measurement of Thermal Neutron Flux in Photo-Neutron Source  

Science Journals Connector (OSTI)

The Photo-Neutron Source (PNS) project is a study ... design, simulation and construction an accelerator based neutron source for Boron Neutron Capture Therapy (BNCT). The system uses ... medical linear accelerat...

A. Taheri; A. Torkamani; A. Pazirandeh…

2013-01-01T23:59:59.000Z

337

Method of positioning tubing within a horizontal well  

SciTech Connect

This patent describes a method of variably and selectively positioning coil tubing in a horizontally drilled well having a generally vertical section, a curve section and a generally horizontal section. It comprises securing a generally hollow tubing guide shoe to one end of a tubing string; inserting the tubing guide shoe and a portion of the tubing string through the generally vertical section and the curve section and into a portion of the generally horizontal section; and inserting coil tubing through the tubing string.

Young, C.E.

1992-06-02T23:59:59.000Z

338

Neutron sources and applications  

SciTech Connect

Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-01-01T23:59:59.000Z

339

Fireside carburization of stainless steel furnace tubes  

SciTech Connect

Most heavy Venezuelan crudes are recognized for having a high total acid number (TAN) that is usually associated with a high tendency to produce naphthenic acid corrosion. To resist this type of corrosion in vacuum heaters, 9Cr-1Mo steel and stainless steels containing molybdenum are usually recommended. In 1993 the original 5Cr-1/2Mo roof tubes of the furnace in a vacuum unit were replaced by stainless steel 316Ti to minimize tube replacement and increase heater reliability. Unexpectedly, some of the new tubes failed after only three years of service, and just one year after undergoing the last turnaround inspection. The damage occurred in the form of deep holes and perforations, starting from the outside tube surface on the fireside. Coke build-up occurred due to severe operating conditions, overheating the tubes on the fireside, above 675 C (1250 F). Metallographic and Scanning Electron Microscopic (SEM) examination revealed internal and external carburization of the material due to the presence of coke and combustion ashes, respectively. The increase in the skin metal temperature facilitated the diffusion of carbon from these carbon-rich deposits into the low carbon content material (0.023 O/O).Depletion of chromium at the grain boundaries due to the massive formation of chromium carbides, resulted in a severe intergranular corrosion attack by molten salts rich in vanadium and sulfur due to asphalt burning. Normal operating practice demands the use of steam for the heater tubes to control coke build-up. This practice had been first reduced and then eliminated, during the past two years prior to the failure, because of economic incentives. This paper describes the root cause analysis conducted to account for these premature tube failures.

Mirabal, E.; Molina, C. [PDVSA-Refineria Isla, Curayao (Netherlands); Mayorga, A.; Hau, J.L. [PDVSA-Intevep, Caracas (Venezuela)

1999-11-01T23:59:59.000Z

340

Study on the method with associated particle for measuring the neutron yield of D–D neutron generator†  

Science Journals Connector (OSTI)

Abstract A measuring method with associated particles has been developed and tested to monitor the D–D neutron yield at a ZF-300 intense neutron generator in Lanzhou University. The experiment has been carried out in an environment of 236 keV and 0.5 mA of deuteron beam with a thick titanium-filmed target of molybdenum substrate at 135° for proton emission. All correction factors, including anisotropy factors and the yield ratio of neutron and proton, have been calculated, and the uncertainty of calculation result has been discussed.

Yan Yan; Xiaolong Lu; Zheng Wei; Siqi Yan; Changlin Lan; Junrun Wang; Jie Wang; Zeen Yao

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Crystal Driven Neutron Source: A New Paradigm for Miniature Neutron Sources  

SciTech Connect

Neutron interrogation techniques have specific advantages for detection of hidden, shielded, or buried threats over other detection modalities in that neutrons readily penetrate most materials providing backscattered gammas indicative of the elemental composition of the potential threat. Such techniques have broad application to military and homeland security needs. Present neutron sources and interrogation systems are expensive and relatively bulky, thereby making widespread use of this technique impractical. Development of a compact, high intensity crystal driven neutron source is described. The crystal driven neutron source approach has been previously demonstrated using pyroelectric crystals that generate extremely high voltages when thermal cycled [1-4]. Placement of a sharpened needle on the positively polarized surface of the pyroelectric crystal results in sufficient field intensification to field ionize background deuterium molecules in a test chamber, and subsequently accelerate the ions to energies in excess of {approx}100 keV, sufficient for either D-D or D-T fusion reactions with appropriate target materials. Further increase in ion beam current can be achieved through optimization of crystal thermal ramping, ion source and crystal accelerator configuration. The advantage of such a system is the compact size along with elimination of large, high voltage power supplies. A novel implementation discussed incorporates an independently controlled ion source in order to provide pulsed neutron operation having microsecond pulse width.

Tang, V; Morse, J; Meyer, G; Falabella, S; Guethlein, G; Kerr, P; Park, H G; Rusnak, B; Sampayan, S; Schmid, G; Spadaccini, C; Wang, L

2008-08-08T23:59:59.000Z

342

Spallation Neutron Source  

NLE Websites -- All DOE Office Websites (Extended Search)

D/gim D/gim Spallation Neutron Source SNS is an accelerator-based neutron source. This one-of-a-kind facility pro- vides the most intense pulsed neutron beams in the world. When ramped up to its full beam power of 1.4 MW, SNS will be eight times more powerful than today's best facility. It will give researchers more detailed snapshots of the smallest samples of physical and biological materials than ever before

343

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Industry banner Industry banner Neutron scattering research has applications in practically every field, and neutron research at ORNL is leading to productive partnerships with the industrial and business communities. We welcome proposals for all types of research, including those involving proprietary work. Recent studies have led to discoveries with potential applications in fields such as medicine, energy, and various metals technologies. For more information, please see our recent research highlights. Research Collaborations Industry-Driven Research Benefits Plastics Manufacturing Corning uses VULCAN to test limits of ceramic material for car emission controls, filtration devices Neutrons Probe Inner Workings of Batteries Industry and Neutron Science: Working To Make a Match

344

Neutron wave packet tomography  

E-Print Network (OSTI)

A tomographic technique is introduced in order to determine the quantum state of the center of mass motion of neutrons. An experiment is proposed and numerically analyzed.

G. Badurek; P. Facchi; Y. Hasegawa; Z. Hradil; S. Pascazio; H. Rauch; J. Rehacek; T. Yoneda

2005-03-29T23:59:59.000Z

345

Neutron Science Forum | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

environment for discussion, innovation, and dissemination of information within the neutron scattering community as well as engaging closely related disciplines through...

346

Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

User Office User Program Manager Laura Morris Edwards 865.574.2966 ORNL study uses neutron scattering, supercomputing to demystify forces at play in biofuel production Full...

347

Polarizability of the Neutron  

Science Journals Connector (OSTI)

Experiments on scattering of low-energy neutrons by heavy elements may give information concerning the electric polarizability of the neutron. The relation of the electric polarizability to the low-energy neutron scattering data is developed. One pertinent experiment is discussed and from this an upper bound on the polarizability is obtained. This upper bound to the polarizability ? is an order of magnitude larger than the meson-theoretic estimate of ?. If the value of ? is as small as is predicted by meson theory, or by an analysis of the pion photoproduction data, then it is unlikely to be observed in neutron scattering experiments of the presently achievable accuracy.

R. M. Thaler

1959-05-01T23:59:59.000Z

348

Improved di-neutron cluster model for 6He scattering  

E-Print Network (OSTI)

The structure of the three-body Borromean nucleus 6He is approximated by a two-body di-neutron cluster model. The binding energy of the 2n-\\alpha system is determined to obtain a correct description of the 2n-\\alpha coordinate, as given by a realistic three-body model calculation. The model is applied to describe the break-up effects in elastic scattering of 6He on several targets, for which experimental data exist. We show that an adequate description of the di-neutron-core degree of freedom permits a fairly accurate description of the elastic scattering of 6He on different targets.

A. M. Moro; K. Rusek; J. M. Arias; J. Gomez-Camacho; M. Rodriguez-Gallardo

2007-03-01T23:59:59.000Z

349

Neutron superfluidity and unusual nuclear shapes in neutron stars crusts  

Science Journals Connector (OSTI)

We calculate in the frame-work of a semiclassical model the neutron superfluidity in the crust of neutron stars, accounting for the presence of unusual....

G. Lazzari; F. V. De Blasio

1994-01-01T23:59:59.000Z

350

Neutron capture cross sections for neutron-rich isotopes  

Science Journals Connector (OSTI)

Average continuum (Hauser-Feshbach) and resonance (Breit-Wigner) neutron capture rates for neutron-rich isotopes, determined on the basis of...

B. Leist; W. Ziegert; M. Wiescher…

1985-01-01T23:59:59.000Z

351

Neutron Diffraction Studies of Proteins  

Science Journals Connector (OSTI)

20 November 1980 research-article Neutron Diffraction Studies of Proteins G. A. Bentley S. A. Mason Neutrons interact differently with protein crystals...hydrogen or deuterium atoms diffract neutrons relatively more strongly, but in addition...

1980-01-01T23:59:59.000Z

352

Neutron and Nuclear Science News  

NLE Websites -- All DOE Office Websites (Extended Search)

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Links Neutron and Nuclear Science News Media Links Profiles Events at...

353

Neutron Scattering Methods in Chemistry  

Science Journals Connector (OSTI)

Starting with basic properties of the neutron, this chapter reviews the most important neutron scattering methods that provide valuable information for a ... wide, from standard methods of crystallography to neutron

L. Pusztai

2011-01-01T23:59:59.000Z

354

Neutron Coincidence Counting Studies  

SciTech Connect

The efficiency comparison for measured and simulated responses of a 10B-lined proportional counter and a 3He proportional counter in a close, symmetrical geometry are presented. The measurement geometry was modeled in MCNPX to validate the methods used for simulating the response of both the 3He and 10B-lined tubes. The MCNPX models agree within 1% with the 3He tube measurements and within 3% for the 10B-lined tubes when a 0.75-µm boron-metal lining is used.

Rogers, Jeremy L.; Ely, James H.; Kouzes, Richard T.; Lintereur, Azaree T.; Siciliano, Edward R.

2012-08-31T23:59:59.000Z

355

Physics design of a cold neutron source for KIPT neutron source facility.  

SciTech Connect

Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of a neutron source facility. It is based on the use of an electron accelerator driven subcritical (ADS) facility with low enriched uranium fuel, using the existing electron accelerators at KIPT of Ukraine [1]. The neutron source of the subcritical assembly is generated from the interaction of 100-KW electron beam, which has a uniform spatial distribution and the electron energy in the range of 100 to 200 MeV, with a natural uranium target [2]. The main functions of the facility are the production of medical isotopes and the support of the Ukraine nuclear power industry. Neutron beam experiments and material studies are also included. Over the past two-three decades, structures with characteristic lengths of 100 {angstrom} and correspondingly smaller vibrational energies have become increasingly important for both science and technology [3]. The characteristic dimensions of the microstructures can be well matched by neutrons with longer vibrational wavelength and lower energy. In the accelerator-driven subcritical facility, most of the neutrons are generated from fission reactions with energy in the MeV range. They are slowed down to the meV energy range through scattering reactions in the moderator and reflector materials. However, the fraction of neutrons with energies less than 5 meV in a normal moderator spectrum is very low because of up-scattering caused by the thermal motion of moderator or reflector molecules. In order to obtain neutrons with energy less than 5 meV, cryogenically cooled moderators 'cold neutron sources' should be used to slow down the neutrons. These cold moderators shift the neutron energy spectrum down because the thermal motion of moderator molecules as well as the up-scattering is very small, which provides large gains in intensity of low energy neutrons, E < 5 meV. The accelerator driven subcritical facility is designed with a provision to add a cryogenically cooled moderator system. This cold neutron source could provide the neutrons beams with lower energy, which could be utilized in scattering experiment and material structures analysis. This study describes the performed physics analyses to define and characterize the cold neutron source of the KIPT neutron source facility. The cold neutron source is designed to optimize the cold neutron brightness to the experimental instruments outside the radial heavy concrete shield of the facility. Liquid hydrogen or solid methane with 20 K temperature is used as a cold moderator. Monte Carlo computer code MCNPX [4], with ENDF/B-VI nuclear data libraries, is utilized to calculate the cold neutron source performance and estimate the nuclear heat load to the cold moderator. The surface source generation capability of MCNPX code has been used to provide the possibility of analyzing different design configurations and perform design optimization analyses with reasonable computer resources. Several design configurations were analyzed and their performance were characterized and optimized.

Zhong, Z.; Gohar, Y.; Kellogg, R.; Nuclear Engineering Division

2009-02-17T23:59:59.000Z

356

Neutron Diffraction @ TOPAZ  

NLE Websites -- All DOE Office Websites (Extended Search)

Topaz Guide Bender Topaz Guide Bender Neutron Diffraction @ TOPAZ Workshop on Single Crystal Neutron Diffraction picture 2 September 29 - October 1, 2011 * Spallation Neutron Source * Oak Ridge National Laboratory * Oak Ridge TN, USA TOPAZ 2011 Home Contacts Agenda and Important Deadlines Registration and Payment filler Workshop summary and purpose A workshop on single crystal neutron diffraction will be held at the Spallation Neutron Source at the Oak Ridge National Laboratory (ORNL). It will present invited and contributed talks to showcase cutting edge science and examples where neutron diffraction can make significant contributions; and provide training in neutron structure analysis and sample screening for the preparation of instrument beam-time proposals. TOPAZ is a high resolution wavelength-resolved Laue diffractometer with a versatile sample environment. Commissioning user experiments have demonstrated successfully the instrument capability for structural study of a vitamin B12 derivative, ion distribution in Li-ion battery materials, order and disorder in shape memory intermetallics, magnetic phase transition in multiferroic single crystal and functional thin films. The workshop is directed towards experienced neutron diffraction users and new users alike and encourages members to highlight their research and interest in structure analysis and investigation. The workshop will give opportunity to bring your own single crystal and screen sample quality and scattering power on TOPAZ @ room temperature, to evaluate data collection time and quality for an anticipated experiment. Finally, an opportunity to compose a proposal for neutron beam time (http://neutrons.ornl.gov/users/proposals.shtml) with staff will be provided in the framework of the workshop. The workshop format is well suited for researchers to contribute by showcasing their research and bring their research group or graduate student, who would like to test a single crystal sample. User access training for the ORNL neutron scattering facility will be included. It will be valid for future experiments.

357

Boron Analytical Studies on 10B1-BPA Administration for Neutron Capture Therapy of Malignant Melanoma  

Science Journals Connector (OSTI)

Success of boron neutron capture therapy (NCT) for cancer depends mainly upon selective boron accumulation in the targeted tumor. Since 1987 we have succeeded in treating human melanoma lesions by NCT utilizing10

C. Honda; N. Wadabayashi; K. Yoshino; J. Hiratsuka…

1996-01-01T23:59:59.000Z

358

Neutron activation experiments in radiochemistry  

Science Journals Connector (OSTI)

Neutron activation experiments in radiochemistry ... Describes experimentation involving the neutron activation of a variety of samples irradiated in a subcritical reactor and a paraffin-moderated source. ...

Karl S. Vorres

1960-01-01T23:59:59.000Z

359

Neutron Stars and Fractal Dimensionality  

E-Print Network (OSTI)

We argue that the material inside Neutron stars behaves anomalously with fractal statistics and that in principle, we could induce mini Neutron stars, with the release of energy.

Burra G. Sidharth

2008-05-06T23:59:59.000Z

360

A history of the neutron  

Science Journals Connector (OSTI)

A history of the neutron ... Describes some of the individuals and the work they did leading to the discovery of the neutron. ...

Vasilis Lavrakas

1952-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Neutron and Nuclear Science Publications  

NLE Websites -- All DOE Office Websites (Extended Search)

Publications Recent publications related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science Publications Chi-Nu Publications DANCE Publications GEANIE...

362

Neutron and Nuclear Science News  

NLE Websites -- All DOE Office Websites (Extended Search)

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Nuclear science observations and opportunities at the Los Alamos...

363

Neutron Science Research Areas | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Home | Science & Discovery | Neutron Science | Research Areas SHARE Research Areas Neutron scattering research at ORNL covers four broad research areas: biology and soft...

364

LANSCE School on Neutron Scattering:  

NLE Websites -- All DOE Office Websites (Extended Search)

11 th LANSCE School on Neutron Scattering: Materials at the Mesoscale Lujan Center Los Alamos Neutron Science Center Los Alamos National Laboratory lansce.lanl.govneutronschool...

365

Advances in specular neutron reflectometry  

Science Journals Connector (OSTI)

Specular neutron reflectometry provides a depth profile of the scattering ... material. To date, numerous productive applications of neutron reflectometry have been demonstrated. With the new development ... stil...

C.F. Majkrzak; N.F. Berk

2002-12-01T23:59:59.000Z

366

Power Tube Inc | Open Energy Information  

Open Energy Info (EERE)

Power Tube Inc Power Tube Inc Jump to: navigation, search Name Power Tube Inc Place Houston, Texas Zip 77060 Sector Geothermal energy Product Texan geothermal systems developer. Has developed a new range of geothermal heat exchangers from biodegradable materials. Coordinates 29.76045°, -95.369784° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":29.76045,"lon":-95.369784,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

367

Alternate Materials for Recovery Boiler Superheater Tubes  

SciTech Connect

The ever escalating demands for increased efficiency of all types of boilers would most sensibly be realized by an increase in the steam parameters of temperature and pressure. However, materials and corrosion limitations in the steam generating components, particularly the superheater tubes, present major obstacles to boiler designers in achieving systems that can operate under the more severe conditions. This paper will address the issues associated with superheater tube selection for many types of boilers; particularly chemical recovery boilers, but also addressing the similarities in issues for biomass and coal fired boilers. It will also review our recent study of materials for recovery boiler superheaters. Additional, more extensive studies, both laboratory and field, are needed to gain a better understanding of the variables that affect superheater tube corrosion and to better determine the best means to control this corrosion to ultimately permit operation of recovery boilers at higher temperatures and pressures.

Keiser, James R [ORNL; Kish, Joseph [McMaster University; Singbeil, Douglas [FPInnovations

2009-01-01T23:59:59.000Z

368

Prompt gamma ray neutron activation analysis of cadmium in municipal solid waste  

E-Print Network (OSTI)

EXPERIMENTAL. . 26 PGNAA Assembly. Detection System Background Determination of Detector Shielding. Self-Shielding. Optimal Bag Size and Orientation. . . . . . . . . . . . . . . Detection Limit and Sensitivity. . . . . . . . . . . . . . . . Neutron Flux... solid waste. This study modified a previous setup that was in a shadow- shield arrangement using Pu-Be neutron sources by: more elaborate detector shielding to reduce background levels; and, irradiating the target bilaterally. The system background...

Dendahl, Katherine Hoge

2012-06-07T23:59:59.000Z

369

Conceptual design of spectrum changeable neutron calibration fields in JAERI/FRS  

Science Journals Connector (OSTI)

......PWR, HTGR, FBR), accelerators (48 cases; cyclotron...production, processing), nuclear fuel processing plants...means other than using accelerator-produced neutrons...a Van-de-Graaff accelerator. In the SCNCF, neutron...target, which was vacuum-evaporated on 0......

J. Saegusa; Y. Tanimura; M. Yoshizawa; M. Yoshida

2004-08-01T23:59:59.000Z

370

Category:Neutron Log | Open Energy Information  

Open Energy Info (EERE)

Neutron Log page? For detailed information on Neutron Log, click here. Category:Neutron Log Add.png Add a new Neutron Log Technique Pages in category "Neutron Log" This category...

371

Neutron Capture Therapy  

Science Journals Connector (OSTI)

... . Only those elements which have a high thermal-neutron capture cross-section, such as boron-10, lithium-6, and uranium-235, are useful. This suggestion was first put forward ... was first put forward in 1936 by Locher. The utilization of thermal neutron capture by boron-10 for the treatment of human-brain tumours, chiefly glioblastoma multiforme, has been under investigation ...

1961-09-23T23:59:59.000Z

372

Neutron calibration facilities  

Science Journals Connector (OSTI)

......shut down. A recent development for a thermal neutron calibration field is a neutron guide used at the research reactor GKSS Geesthacht(35). The result is a high-intensity thermal beam providing a flux of up to 106 s1 with a field size of about 2.5 2......

H. Schuhmacher

2004-08-01T23:59:59.000Z

373

Neutron Scattering Software  

NLE Websites -- All DOE Office Websites (Extended Search)

Software Software A new portal for neutron scattering has just been established at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for archival purposes but no new content will be added. We encourage everyone interested in neutron scattering to take full advantage of this exciting new resource for our community. Neutronsources.org Data Formats NeXus: Neutron and X-ray Data Format Crystallographic Binary Format (CBF/imgCIF) Hierarchical Data Format (HDF) Data Analysis and Visualization Data Analysis for Neutron Scattering Experiments (DANSE): distributed data analysis project Large Array Manipulation Program (LAMP): IDL-based data analysis and visualization

374

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Industry and Neutron Science Industry and Neutron Science Industry and Neutron Science: Working To Make a Match "In fundamental research, we want to know everything. Industry wants to know enough to answer a question." Research Contact: Mike Crawford September 2011, Written by Deborah Counce Mike Crawford and Souleymane Diallo Mike Crawford of Dupont (right) and Souleymane Diallo, instrument scientist for the Backscattering Spectrometer at SNS, prepare a material sample for an experiment on the instrument. Industrial users are starting to eye the potential of neutron science for solving problems that can't be solved in any other way. At the same time, the SNS and HFIR neutron science facilities at ORNL are exploring ways to woo such users and to make a match of it, to the benefit of both.

375

Pocked surface neutron detector  

DOE Patents (OSTI)

The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

2003-04-08T23:59:59.000Z

376

Structure of the Neutron  

Science Journals Connector (OSTI)

In an earlier paper, the contribution of the meson current to the electromagnetic structure of the nucleon was calculated by use of the dispersion relations for pion-nucleon scattering. Here the contribution of the nucleon current to the electromagnetic structure of the neutron is obtained analogously by use of the dispersion relations for neutron-proton scattering. Only the contribution from the one-pion and two-pion states of nucleon-nucleon scattering is considered. It is found that both states reduce the neutron-electron potential, i.e., leads to a smaller charge radius of the neutron. The contribution from the deuteron state is shown to be negligible. The resulting mean-square radii of the neutron, including the contributions of both meson and nucleon current, are (0.23×10-13cm)2 for the charge distribution and (0.41×10-13cm)2 for the magnetic moment distribution with f2=0.08.

Katsumi Tanaka

1959-01-15T23:59:59.000Z

377

SINGLE CRYSTAL NEUTRON DIFFRACTION.  

SciTech Connect

Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

KOETZLE,T.F.

2001-03-13T23:59:59.000Z

378

Cyclotrons to Make Neutrons & Radioactive Targets for SBSS at...  

Office of Science (SC) Website

training of young scientists for the future workforce in this area. Intense light ion beams, such as protons, deuterons, He-3 and He-4, from a cyclotron such as the 88-Inch...

379

Development of a Versatile Laser-Ultrasonic System and Application to the Online Measurement for Process Control of Wall Thickness and Eccentricity of Seamless Tubes  

SciTech Connect

A system for the online, non-contact measurement of wall thickness in steel seamless mechanical tubing has been developed and demonstrated at a tubing production line at the Timken Company in Canton, Ohio. The system utilizes laser-generation of ultrasound and laser-detection of time of flight with interferometry, laser-doppler velocimetry and pyrometry, all with fiber coupling. Accuracy (<1% error) and precision (1.5%) are at targeted levels. Cost and energy savings have exceeded estimates. The system has shown good reliability in measuring over 200,000 tubes in its first six months of deployment.

Robert V. Kolarik II

2002-10-23T23:59:59.000Z

380

Digital radiographic systems detect boiler tube cracks  

SciTech Connect

Boiler water wall leaks have been a major cause of steam plant forced outages. But conventional nondestructive evaluation techniques have a poor track record of detecting corrosion fatigue cracking on the inside surface of the cold side of waterwall tubing. EPRI is performing field trials of a prototype direct-digital radiographic system that promises to be a game changer. 8 figs.

Walker, S. [EPRI, Charlotte, NC (United States)

2008-06-15T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Stress-Assisted Corrosion in Boiler Tubes  

SciTech Connect

A number of industrial boilers, including in the pulp and paper industry, needed to replace their lower furnace tubes or decommission many recovery boilers due to stress-assisted corrosion (SAC) on the waterside of boiler tubes. More than half of the power and recovery boilers that have been inspected reveal SAC damage, which portends significant energy and economic impacts. The goal of this project was to clarify the mechanism of stress-assisted corrosion (SAC) of boiler tubes for the purpose of determining key parameters in its mitigation and control. To accomplish this in-situ strain measurements on boiler tubes were made. Boiler water environment was simulated in the laboratory and effects of water chemistry on SAC initiation and growth were evaluated in terms of industrial operations. Results from this project have shown that the dissolved oxygen is single most important factor in SAC initiation on carbon steel samples. Control of dissolved oxygen can be used to mitigate SAC in industrial boilers. Results have also shown that sharp corrosion fatigue and bulbous SAC cracks have similar mechanism but the morphology is different due to availability of oxygen during boiler shutdown conditions. Results are described in the final technical report.

Preet M Singh; Steven J Pawel

2006-05-27T23:59:59.000Z

382

Remote Opening and Sealing of Metal Tubes  

Science Journals Connector (OSTI)

``One?shot'' methods of opening and sealing metal tubes are described. These methods were developed for taking high altitude atmospheric samples in metal bottles carried aloft by rockets and are performed by pyrotechnic means. The sealing is done by cold welding.

L. T. Loh; H. W. Neill; M. H. Nichols; E. A. Wenzel

1952-01-01T23:59:59.000Z

383

"Fine grain Nb tube for SRF cavities"  

SciTech Connect

Superconducting radio frequency (SRF) cavities used in charged particle linear accelerators, are currently fabricated by deep drawing niobium sheets and welding the drawn dishes together. The Nb sheet has a non-uniform microstructure, which leads to unpredictable cavity shape and surface roughness, and inconsistent "spring-back" during forming. In addition, weld zones cause hot spots during cavity operation. These factors limit linear accelerator performance and increase cavity manufacturing cost. Equal channel angular extrusion (ECAE) can be used to refine and homogenize the microstructure of Nb tube for subsequent hydroforming into SRF cavities. Careful selection of deformation and heat treatment conditions during the processing steps can give a uniform and consistent microstructure in the tube, leading to improved deformability and lower manufacturing costs. Favorable microstructures were achieved in short test samples of RRR Nb tube, which may be particularly suitable for hydroforming into SRF cavity strings. The approach demonstrated could be applicable to microstructure engineering of other tube materials including tantalum, titanium, and zirconium.

Robert E. Barber

2012-07-08T23:59:59.000Z

384

Neutron LifetimeNeutron Lifetime IUCF Colloquium April 13,  

E-Print Network (OSTI)

Neutron LifetimeNeutron Lifetime IUCF Colloquium April 13, 2007 Albert Steyerl Department 940 878.5±0.8 885.7±0.8 new result neutronlifetime(),s year world average Neutron lifetime data #12 world average Neutron lifetime data A. Serebrov et al. 2005Storage of ultra-cold neutrons878.5 ±±±± 0

Steyerl, Albert

385

Condensation in horizontal heat exchanger tubes  

SciTech Connect

Many innovative reactor concepts for Generation III nuclear power plants use passive safety equipment for residual heat removal. These systems use two phase natural circulation. Heat transfer to the coolant results in a density difference providing the driving head for the required mass flow. By balancing the pressure drop the system finds its operational mode. Therefore the systems depend on a strong link between heat transfer and pressure drop determining the mass flow through the system. In order to be able to analyze these kind of systems with the help of state of the art computer codes the implemented numerical models for heat transfer, pressure drop or two phase flow structure must be able to predict the system performance in a wide parameter range. Goal of the program is to optimize the numerical models and therefore the performance of computer codes analyzing passive systems. Within the project the heat transfer capacity of a heat exchanger tube will be investigated. Therefore the tube will be equipped with detectors, both temperature and pressure, in several directions perpendicular to the tube axis to be able to resolve the angular heat transfer. In parallel the flow structure of a two phase flow inside and along the tube will be detected with the help of x-ray tomography. The water cooling outside of the tube will be realized by forced convection. It will be possible to combine the flow structure measurement with an angular resolved heat transfer for a wide parameter range. The test rig is set up at the TOPLFOW facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), so that it will be possible to vary the pressure between 5 and 70 bar. The steam mass content will be varied between 0 and 100 percent. The results will be compared to the large scaled Emergency Condenser Tests performed at the INKA test facility in Karlstein (Germany). The paper will explain the test setup and the status of the project will be presented. (authors)

Leyer, S.; Zacharias, T.; Maisberger, F.; Lamm, M. [AREVA NP GmbH, Paul-Gossen-Strasse 100, Erlangen, 91052 (Germany); Vallee, C.; Beyer, M.; Hampel, U. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstrasse 400, Dresden, 01328 (Germany)

2012-07-01T23:59:59.000Z

386

Polarized internal target apparatus  

DOE Patents (OSTI)

A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

Holt, R.J.

1984-10-10T23:59:59.000Z

387

Polarized internal target apparatus  

DOE Patents (OSTI)

A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

Holt, Roy J. (Downers Grove, IL)

1986-01-01T23:59:59.000Z

388

Calibration of a Neutron Hydroprobe for Moisture Measurements in Small-Diameter Steel-Cased Boreholes  

SciTech Connect

Computation of soil moisture content from thermalized neutron counts for the T-Farm Interim cover requires a calibration relationship but none exists for 2-in tubes. A number of calibration options are available for the neutron probe, including vendor calibration, field calibration, but none of these methods were deemed appropriate for the configuration of interest. The objective of this work was to develop a calibration relation for converting neutron counts measured in 2-in access tubes to soil water content. The calibration method chosen for this study was a computational approach using the Monte Carlo N-Particle Transport Code (MCNP). Model calibration was performed using field measurements in the Hanford calibration models with 6-in access tubes, in air and in the probe shield. The bet-fit model relating known water content to measured neutron counts was an exponential model that was essentially equivalent to that currently being used for 6-in steel cased wells. The MCNP simulations successfully predicted the neutron count rate for the neutron shield and the three calibration models for which data were collected in the field. However, predictions for air were about 65% lower than the measured counts . This discrepancy can be attributed to uncertainties in the configuration used for the air measurements. MCNP-simulated counts for the physical models were essentially equal to the measured counts with values. Accurate prediction of the response in 6-in casings in the three calibration models was motivation to predict the response in 2-in access tubes. Simulations were performed for six of the seven calibration models as well as 4 virtual models with the entire set covering a moisture range of 0 to 40%. Predicted counts for the calibration models with 2-in access tubes were 40 to 50% higher than in the 6-inch tubes. Predicted counts for water were about 60% higher in the 2-in tube than in the 6-in tube. The discrepancy between the 2-in and 6-in tube can be attributed to the smaller air gap between the probe and the 2-in access tube. The best-fit model relating volumetric water content to count ratio (CR) is of the form e^A x CR^B with A=0.3596 ± 0.0216 and B=0.4629 ± 0.0629 and r^2= 0.9998. It is recommended that the calibration function based on the count ratio, rather than raw counts, be used to avoid the effects of electronic noise in the probe that may arise due to the conditions at the time of measurement. These results suggest that the MCNP code can be used to extend calibrations for the neutron probe to different conditions including access tube size as well as composition without the need to construct additional physical models.

Ward, Anderson L.; Wittman, Richard S.

2009-08-01T23:59:59.000Z

389

Characterization of Friction Stir Welded Tubes by Means of Tube Bulge Test  

SciTech Connect

Mechanical properties of friction stir welded joints are generally evaluated by means of conventional tensile test. This testing method might provide insufficient information because maximum strain obtained in tensile test before necking is small; moreover, the application of tensile test is limited when the joint path is not linear or even when the welds are executed on curved surfaces. Therefore, in some cases, it would be preferable to obtain the joints properties from other testing methods. Tube bulge test can be a valid solution for testing circumferential or longitudinal welds executed on tubular workpieces. The present work investigates the mechanical properties and the formability of friction stir welded tubes by means of tube bulge tests. The experimental campaign was performed on tubular specimens having a thickness of 3 mm and an external diameter of 40 mm, obtained starting from two semi-tubes longitudinally friction stir welded. The first step, regarding the fabrication of tubes, was performed combining a conventional forming process and friction stir welding. Sheets in Al-Mg-Si-Cu alloy AA6060 T6 were adopted for this purpose. Plates having a dimension of 225x60 mm were bent (with a bending axis parallel to the main dimension) in order to obtain semi-tubes. A particular care was devoted to the fabrication of forming devices (punch and die) in order to minimize the springback effects. Semi-tubes were then friction stir welded by means of a CNC machine tool. Some preliminary tests were carried out by varying the welding parameters, namely feed rate and rotational speed. A very simple tool having flat shoulder and cylindrical pin was used. The second step of the research was based on testing the welded tubes by means of tube bulge test. A specific equipment having axial actuators with a conical shape was adopted for this study. Some analyses were carried out on the tubes bulged up to a certain pressure level. In particular, the burst pressure and the wall thickness were measured for each tested tube.

D'Urso, G.; Longo, M.; Giardini, C. [University of Bergamo-Dept. of Design and Technologies-Italy-Viale Marconi 5, 24044 Dalmine (Italy)

2011-05-04T23:59:59.000Z

390

Commissioning of intensity modulated neutron radiotherapy (IMNRT)  

SciTech Connect

Purpose: Intensity modulated neutron radiotherapy (IMNRT) has been developed using inhouse treatment planning and delivery systems at the Karmanos Cancer Center/Wayne State University Fast Neutron Therapy facility. The process of commissioning IMNRT for clinical use is presented here. Results of commissioning tests are provided including validation measurements using representative patient plans as well as those from the TG-119 test suite. Methods: IMNRT plans were created using the Varian Eclipse optimization algorithm and an inhouse planning system for calculation of neutron dose distributions. Tissue equivalent ionization chambers and an ionization chamber array were used for point dose and planar dose distribution comparisons with calculated values. Validation plans were delivered to water and virtual water phantoms using TG-119 measurement points and evaluation techniques. Photon and neutron doses were evaluated both inside and outside the target volume for a typical IMNRT plan to determine effects of intensity modulation on the photon dose component. Monitor unit linearity and effects of beam current and gantry angle on output were investigated, and an independent validation of neutron dosimetry was obtained. Results: While IMNRT plan quality is superior to conventional fast neutron therapy plans for clinical sites such as prostate and head and neck, it is inferior to photon IMRT for most TG-119 planning goals, particularly for complex cases. This results significantly from current limitations on the number of segments. Measured and calculated doses for 11 representative plans (six prostate/five head and neck) agreed to within -0.8 {+-} 1.4% and 5.0 {+-} 6.0% within and outside the target, respectively. Nearly all (22/24) ion chamber point measurements in the two phantom arrangements were within the respective confidence intervals for the quantity [(measured-planned)/prescription dose] derived in TG-119. Mean differences for all measurements were 0.5% (max = 7.0%) and 1.4% (max = 4.1%) in water and virtual water, respectively. The mean gamma pass rate for all cases was 92.8% (min = 88.6%). These pass rates are lower than typically achieved with photon IMRT, warranting development of a planar dosimetry system designed specifically for IMNRT and/or the improvement of neutron beam modeling in the penumbral region. The fractional photon dose component did not change significantly in a typical IMNRT plan versus a conventional fast neutron therapy plan, and IMNRT delivery is not expected to significantly alter the RBE. All other commissioning results were considered satisfactory for clinical implementation of IMNRT, including the external neutron dose validation, which agreed with the predicted neutron dose to within 1%. Conclusions: IMNRT has been successfully commissioned for clinical use. While current plan quality is inferior to photon IMRT, it is superior to conventional fast neutron therapy. Ion chamber validation results for IMNRT commissioning are also comparable to those typically achieved with photon IMRT. Gamma pass rates for planar dose distributions are lower than typically observed for photon IMRT but may be improved with improved planar dosimetry equipment and beam modeling techniques. In the meantime, patient-specific quality assurance measurements should rely more heavily on point dose measurements with tissue equivalent ionization chambers. No significant technical impediments are anticipated in the clinical implementation of IMNRT as described here.

Burmeister, Jay; Snyder, Michael [Karmanos Cancer Center, Wayne State University School of Medicine, Detroit, Michigan 48201 (United States); Spink, Robyn; Liang Liang; Bossenberger, Todd; Halford, Robert [Karmanos Cancer Center, Detroit, Michigan 48201 (United States); Brandon, John [Michigan State University, East Lansing, Michigan 48201 (United States); Delauter, Jonathan [Wayne State University School of Medicine, Detroit, Michigan 48201 (United States)

2013-02-15T23:59:59.000Z

391

Hyperons in neutron stars  

E-Print Network (OSTI)

Using the Dirac-Brueckner-Hartree-Fock approach, the properties of neutron-star matter including hyperons are investigated. In the calculation, we consider both time and space components of the vector self-energies of baryons as well as the scalar ones. Furthermore, the effect of negative-energy states of baryons is partly taken into account. We obtain the maximum neutron-star mass of $2.08\\,M_{\\odot}$, which is consistent with the recently observed, massive neutron stars. We discuss a universal, repulsive three-body force for hyperons in matter.

Katayama, Tetsuya

2015-01-01T23:59:59.000Z

392

Tests of time reversal in neutron?nucleus scattering  

Science Journals Connector (OSTI)

Experiments to test time?reversal invariance are discussed. The experiments are based on observables constructed from the momentum and spin vectors of epithermal neutrons and from the spin of an aligned or polarized target. It is shown that the proposed tests are detailed balance tests of time?reversal invariance. The status of the experiments is briefly reviewed.

J. David Bowman

1988-01-01T23:59:59.000Z

393

The photonuclear neutron and gamma-ray backgrounds in the fast ignition experiment  

SciTech Connect

In the fast-ignition scheme, very hard x-rays (hereinafter referred to as {gamma}-rays) are generated by Bremsstrahlung radiation from fast electrons. Significant backgrounds were observed around the deuterium-deuterium fusion neutron signals in the experiment in 2010. In this paper the backgrounds were studied in detail, based on Monte Carlo simulations, and they were confirmed to be {gamma}-rays from the target, scattered {gamma}-rays from the experimental bay walls ({gamma}{sup Prime }-rays), and neutrons generated by ({gamma}, n) reactions in either the target vacuum chamber or the diagnostic instruments ({gamma}-n neutrons).

Arikawa, Y.; Nagai, T.; Hosoda, H.; Abe, Y.; Kojima, S.; Fujioka, S.; Sarukura, N.; Nakai, M.; Shiraga, H.; Azechi, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka Suita (Japan); Ozaki, T. [National Institution Fusion Science, 322-6 Oroshi-cho, Toki-city, Gifu (Japan)

2012-10-15T23:59:59.000Z

394

Refrigerant forced-convection condensation inside horizontal tubes  

E-Print Network (OSTI)

Condensing heat transfer rates inside a horizontal tube were investigated -for large quality changes across the tube. The proposed correlation is a modification of the work of Rohsenow, Webber and Ling [29]. The result of ...

Bae, Soonhoon

1968-01-01T23:59:59.000Z

395

Corrosion Failure of an In-service Economizer Tube  

Science Journals Connector (OSTI)

This investigation was primarily aimed to examine the in-service failure of an economizer tube. Apart from preliminary visual examination, ... thickness hole in the weld region of the economizer tube. This water ...

H. Roy; P. Sharma; D. Ghosh; A. K. Shukla

2014-08-01T23:59:59.000Z

396

Delayed hydride cracking behavior for ZIRCALOY-2 tubing  

Science Journals Connector (OSTI)

The delayed hydride cracking (DHC) behavior for ZIRCALOY-2 tubing was characterized at temperatures ranging from 93 °C to 288 °C. Testing was performed on the three types of pressure tubes that were used in th...

F. H. Huang; W. J. Mills

1991-09-01T23:59:59.000Z

397

Analyzing the Effects of Neutron Polarizabilities in Elastic Compton Scattering off ${}^3He$  

E-Print Network (OSTI)

Motivated by the fact that a polarized ${}^3He$ nucleus behaves as an `effective' neutron target, we examine manifestations of neutron electromagnetic polarizabilities in elastic Compton scattering from the Helium-3 nucleus. We calculate both unpolarized and double-polarization observables using chiral perturbation theory to next-to-leading order (${\\mathcal O}(e^2 Q)$) at energies, $\\omega \\lsim m_{\\pi}$, where $m_{\\pi}$ is the pion mass. Our results show that the unpolarized differential cross section can be used to measure neutron electric and magnetic polarizabilities, while two double-polarization observables are sensitive to different linear combinations of the four neutron spin polarizabilities.

Deepshikha Shukla; Andreas Nogga; Daniel R. Phillips

2008-12-01T23:59:59.000Z

398

Simulation of neutrons produced by high-energy muons underground  

Science Journals Connector (OSTI)

This article describes the Monte Carlo simulation used to interpret the measurement of the muon-induced neutron flux in the Boulby Underground Laboratory (North Yorkshire, UK), recently performed using a large scintillator veto deployed around the ZEPLIN-II WIMP detector. Version 8.2 of the GEANT4 toolkit was used after relevant benchmarking and validation of neutron production models. In the direct comparison between Monte Carlo and experimental data, we find that the simulation produces a 1.8 times higher neutron rate, which we interpret as over-production in lead by GEANT4. The dominance of this material in neutron production allows us to estimate the absolute neutron yield in lead as (1.31 ± 0.06)×10?3 neutrons/muon/(g/cm2) for a mean muon energy of 260 GeV. Simulated nuclear recoils due to muon-induced neutrons in the ZEPLIN-II target volume (?1-year exposure) showed that, although a small rate of events is expected from this source of background in the energy range of interest for dark matter searches, no event survives an anti-coincidence cut with the veto.

A. Lindote; H.M. Araújo; V.A. Kudryavtsev; M. Robinson

2009-01-01T23:59:59.000Z

399

2010 American Conference on Neutron Scattering (ACNS 2010)  

SciTech Connect

The ACNS provides a focal point for the national neutron user community to strengthen ties within this diverse group, while at the same time promoting neutron research among colleagues in related disciplines identified as “would-be” neutron users. The American Conference on Neutron Scattering thus serves a dual role as a national user meeting and a scientific meeting. As a venue for scientific exchange, the ACNS showcases recent results and provides forums for scientific discussion of neutron research in diverse fields such as hard and soft condensed matter, liquids, biology, magnetism, engineering materials, chemical spectroscopy, crystal structure, and elementary excitations, fundamental physics and development of neutron instrumentation through a combination of invited talks, contributed talks and poster sessions. As a “super-user” meeting, the ACNS fulfills the main objectives of users' meetings previously held periodically at individual national neutron facilities, with the advantage of a larger and more diverse audience. To this end, each of the major national neutron facilities (NIST, LANSCE, HFIR and SNS) have an opportunity to exchange information and update users, and potential users, of their facility. This is also an appropriate forum for users to raise issues that relate to the facilities. For many of the national facilities, this super-user meeting should obviate the need for separate user meetings that tax the time, energy and budgets of facility staff and the users alike, at least in years when the ACNS is held. We rely upon strong participation from the national facilities. The NSSA intends that the American Conference on Neutron Scattering (ACNS) will occur approximately every two years, but not in years that coincide with the International or European Conferences on Neutron Scattering. The ACNS is to be held in association with one of the national neutron centers in a rotating sequence, with the host facility providing local organization and planning assistance. Additional logistical support is being provided this year through a partnership with the conferencing office of the Materials Research Society (MRS). The ACNS, targeting the entire potential neutron North American user community, complements the annual NIST, ANL and LANSCE neutron and scattering schools which give hands-on experience primarily to graduate students who anticipate using neutron scattering in their thesis research. The summer schools are promoted at the ACNS and represent a natural path for students to take after being inspired by the activities of the ACNS.

Professor Simon Billinge

2011-06-17T23:59:59.000Z

400

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

PartTec PartTec ORNL, PartTec Inc. Licensing Agreement ORNL and PartTec sign licensing agreement (Front) ORNL Deputy Director for Science & Technology Thomas Zacharia and PartTec CEO Herschel Workman. (Back) Bruce Hannan (SNS), PartTec production manager Craig Kline, Rick Riedel (SNS), Jason Hodges (SNS) and Ron Cooper (SNS). The SNS guys were on the development team. Representatives from Oak Ridge National Laboratory and PartTec, an Indiana-based firm, formally signed a licensing agreement Thursday, Aug. 12, to market an advanced neutron detector system developed for the Spallation Neutron Source. The Shifting Scintillator Neutron Detector can determine the time and position of captured neutrons, which enables researchers to obtain very accurate time-of-flight measurements.

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Education | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Education banner Education banner Sunil Sinha A Chat with Sunil Sinha, Distinguished Professor of Physics at the University of California-San Diego and speaker at the recent CNMS-SNS Research Forum more... The purpose of the Spallation Neutron Source and the High Flux Isotope Reactor is to facilitate neutron scattering as an integral tool for scientific research and technological development across many scientific and engineering domains within the scientific, academic,and industrial communities. Coupled with this role is a recognized need to inspire, educate, and facilitate the next generation of users and hence foster enhanced use of the unique neutron scattering facilities at ORNL. This is the central theme of the education activities within the Neutron Sciences Directorate (NScD).

402

ORNL Neutron Sciences Instruments  

NLE Websites -- All DOE Office Websites (Extended Search)

Instruments banner Instruments banner ORNL Neutron Sciences Instruments SNS and HFIR provide researchers with two complementary world-class suites of neutron scattering instruments and beam lines. All the instruments are supported by a variety of sample environments and data analysis and visualization capabilities. Before submitting a proposal for a specific instrument, please contact the appropriate instrument scientist to make sure your research is feasible for that instrument. Instruments Currently Available to Users SNS Beam Line Instrument Name HFIR Beam Line Instrument Name 1B NOMAD Nanoscale-Ordered Materials Diffractometer CG-1 Development Beam Line 2 BASIS Backscattering Spectrometer CG-1D IMAGING Neutron Imaging Prototype Facility 3 SNAP Spallation Neutrons and Pressure Diffractometer CG-2 GP-SANS

403

Pulsed Neutron Powder Diffraction  

Science Journals Connector (OSTI)

The nature and scope of powder diffraction with a white, pulsed beam of neutrons is discussed. Analysis of the data by the Rietveld profile technique is described in brief, and a range of applications in solid...

A. K. Cheetham

1988-01-01T23:59:59.000Z

404

Neutron Science Center  

NLE Websites -- All DOE Office Websites (Extended Search)

to have rare opportunity to tour Neutron Science Center May 10, 2011 LANL Rosenfest will celebrate life of LANSCE founder Louis Rosen and offer tour LOS ALAMOS, New Mexico, May 10,...

405

Scattering of Slow Neutrons  

Science Journals Connector (OSTI)

1 September 1937 research-article Scattering of Slow Neutrons M. Goldhaber G. H. Briggs The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings...

1937-01-01T23:59:59.000Z

406

Neutron Diffraction Texture Analysis  

Science Journals Connector (OSTI)

...conducted at Chalk River (Canada), Geesthacht (Germany), LLB (France) and NIST...deformed limestone that was measured at Geesthacht with this method. It is also possible...with monochromatic neutrons at GKSS, Geesthacht. Equal area projection, linear contours...

Hans-Rudolf Wenk

407

Neutron stars - thermal emitters  

E-Print Network (OSTI)

Confronting theoretical models with observations of thermal radiation emitted by neutron stars is one of the most important ways to understand the properties of both, superdense matter in the interiors of the neutron stars and dense magnetized plasmas in their outer layers. Here we review the theory of thermal emission from the surface layers of strongly magnetized neutron stars, and the main properties of the observational data. In particular, we focus on the nearby sources for which a clear thermal component has been detected, without being contaminated by other emission processes (magnetosphere, accretion, nebulae). We also discuss the applications of the modern theoretical models of the formation of spectra of strongly magnetized neutron stars to the observed thermally emitting objects.

Potekhin, A Y; Pons, J A

2014-01-01T23:59:59.000Z

408

ORIGINAL ARTICLE Yield prediction for seamless tubing processes  

E-Print Network (OSTI)

tubing process 1 Introduction Pipe products made from carbon and alloy steel are commonly used in oil and natural gas exploration and production, fluid transmission, and the construction indus- try. A market an increasing demand for seamless tubing for gas and oil production [1]. Steel tubes are made by several

Huang, Samuel H.

409

Instability characteristics of fluidelastic instability of tube rows in crossflow  

SciTech Connect

An experimental study is reported to investigate the jump phenomenon in critical flow velocities for tube rows with different pitch-to-diameter ratios and the excited and intrinsic instabilities for a tube row with a pitch-to-diameter ratio of 1.75. The experimental data provide additional insights into the instability phenomena of tube arrays in crossflow. 9 refs., 10 figs.

Chen, S.S.; Jendrzejczyk, J.A.

1986-04-01T23:59:59.000Z

410

ACCELERATOR TUBES H. R. McK. HYDER  

E-Print Network (OSTI)

ACCELERATOR TUBES H. R. McK. HYDER Nuclear Physics Laboratory, University of Oxford, Oxford OX1 3RH The characteristics and performance of accelerator tubes required by the new generation of large tandem accelerators conclusions are drawn about future progress and developments. ACCELERATOR TUBES AND INSULATORS. 1

Paris-Sud XI, Université de

411

Department of Mechanical Engineering Spring 2010 Wellbore Coil Tubing  

E-Print Network (OSTI)

PENNSTATE Department of Mechanical Engineering Spring 2010 Wellbore Coil Tubing Overview In BP reaching the bottom of the wellbore utilizing a pre- loaded constant force spring. The coiled tubing's North American Gas Division, there are approximately 800 wellbores with coiled tubing installed

Demirel, Melik C.

412

Finned Tube With Vortex Generators For A Heat Exchanger.  

DOE Patents (OSTI)

A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at least one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

Sohal, Monohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

2004-09-14T23:59:59.000Z

413

Clifford G. Shull, Neutron Diffraction, Hydrogen Atoms, and Neutron  

Office of Scientific and Technical Information (OSTI)

Clifford Shull, Neutron Diffraction, and Neutron Scattering Clifford Shull, Neutron Diffraction, and Neutron Scattering Resources with Additional Information Clifford G. Shull was awarded the 1994 Nobel Prize in Physics "for the development of the neutron diffraction technique". 'Professor Shull's prize was awarded for his pioneering work in neutron scattering, a technique that reveals where atoms are within a material like ricocheting bullets reveal where obstacles are in the dark. Clifford Shull Photo Courtesy of Oak Ridge National Laboratory When a beam of neutrons is directed at a given material, the neutrons bounce off, or are scattered by, atoms in the sample being investigated. The neutrons' directions change, depending on the location of the atoms they hit, and a diffraction pattern of the atoms' positions can then be obtained.

414

Data Analysis & Visualization | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Data Analysis and Visualization SHARE Neutron Data Analysis and Visualization As the data sets generated by the increasingly powerful neutron scattering instruments at HFIR...

415

Science Education Programs | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

with Neutrons Graduate & Post-doctoral Programs Student & Teacher Programs Science Forum Neutron Scattering Tutorials Kids' Corner NScD Careers Supporting Organizations Neutron...

416

Fast Pulsing Neutron Generators for Security Application  

E-Print Network (OSTI)

FAST PULSING NEUTRON GENERATORS FOR SECURITY APPLICATION* Q.time/fast pulsing neutron generator is needed primarily forA compact neutron generator, currently being developed in

Ji, Q.

2010-01-01T23:59:59.000Z

417

Published Research 2007 | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

7 7 Most publications are in Adobe Portable Document Format. Download Adobe Reader. For more information about any of these publications, please contact the Neutrons Sciences Communications Office. Primary Author Index: A B C D E F G H I J K L M N O P R S T U V W X Y Z A R. Alarcon, "Fundamental physics with cold and ultracold neutrons," Revista Mexicana De Fisica 53, 125-127 (February 2007). Albert Einstein College of Medicine, Newsline, "RIT Targeting of HIV-Infected Cells," Journal of Nuclear Medicine 48 (1), 14N (2007). A. Aleksandrov, C. Deibele, and T. Roseberry, "New Design of the SNS MEBT Chopper Deflector," Proc. of the 2007 Particle Accelerator Conference, 1817-1819, Albuquerque, New Mexico, June 25-29, 2007. A. Aleksandrov, S. Assadi, W. Blokland, P. Chu, S. Cousineau, V.

418

Published Research 2011 | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

1 1 Most publications are in Adobe Portable Document Format. Download Adobe Reader. For more information about any of these publications, please contact the Neutrons Sciences Communications Office. Primary Author Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A Abdou A., Wendel M., Riemer B., Volpenhein E., Brewster R., "Two-phase flow simulations of protective gas layer for Spallation Neutron Source target", Proceedings of the ASME 2011 International Mechanical Engineering Congress & Exposition, IMECE2011-64346. Abdulbaki M. K., "Nanoparticle effects on polymer crystallization and dynamics", University of Houston. Abell D. T., Bruhwiler D. L., Choi Y., Mahalingam S., Stoltz P., Han B., Stock M. P., "Simulation of H- beam chopping in a solenoid-based

419

Magnetically attached sputter targets  

DOE Patents (OSTI)

An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

Makowiecki, D.M.; McKernan, M.A.

1994-02-15T23:59:59.000Z

420

Leading neutron spectra  

E-Print Network (OSTI)

It is shown that the observation of the spectra of leading neutrons from proton beams can be a good probe of absorptive and migration effects. We quantify how these effects modify the Reggeized pion-exchange description of the measurements of leading neutrons at HERA. We are able to obtain a satisfactory description of all the features of these data. We also briefly discuss the corresponding data for leading baryons produced in hadron-hadron collisions.

A. B. Kaidalov; V. A. Khoze; A. D. Martin; M. G. Ryskin

2006-02-23T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Color Magnetic Flux Tubes in Dense QCD  

E-Print Network (OSTI)

QCD is expected to be in the color-flavor locking phase in high baryon density, which exhibits color superconductivity. The most fundamental topological objects in the color superconductor are non-Abelian vortices which are topologically stable color magnetic flux tubes. We present numerical solutions of the color magnetic flux tube for diverse choices of the coupling constants. We also analytically study its asymptotic profiles and find that they are different from the case of usual superconductors. We propose the width of color magnetic fluxes and find that it is larger than naive expectation of the Compton wave length of the massive gluon when the gluon mass is larger than the scalar mass.

Minoru Eto; Muneto Nitta

2009-07-07T23:59:59.000Z

422

Color magnetic flux tubes in dense QCD  

SciTech Connect

QCD is expected to be in the color-flavor locking phase in high baryon density, which exhibits color superconductivity. The most fundamental topological objects in the color superconductor are non-Abelian vortices which are topologically stable color magnetic flux tubes. We present numerical solutions of the color magnetic flux tube for diverse choices of the coupling constants based on the Ginzburg-Landau Lagrangian. We also analytically study its asymptotic profiles and find that they are different from the case of usual superconductors. We propose the width of color magnetic fluxes and find that it is larger than naive expectation of the Compton wavelength of the massive gluon when the gluon mass is larger than the scalar mass.

Eto, Minoru [Theoretical Physics Laboratory, RIKEN, Saitama 351-0198 (Japan); Nitta, Muneto [Department of Physics, and Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Yokohama, Kanagawa 223-8521 (Japan)

2009-12-15T23:59:59.000Z

423

Coupled-cavity drift-tube linac  

DOE Patents (OSTI)

A coupled-cavity drift-tube linac (CCDTL) combines features of the Alvarez drift-tube linac (DTL) and the {pi}-mode coupled-cavity linac (CCL). In one embodiment, each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between accelerating gaps is {beta}{lambda}, where {lambda} is the free-space wavelength of the resonant mode. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180 degrees. The chain of cavities operates in a {pi}/2 structure mode so the coupling cavities are nominally unexcited. The CCDTL configuration provides an rf structure with high shunt impedance for intermediate velocity charged particles, i.e., particles with energies in the 20-200 MeV range. 5 figs.

Billen, J.H.

1996-11-26T23:59:59.000Z

424

Thermal neutron detection using a silicon pad detector and {sup 6}LiF removable converters  

SciTech Connect

A semiconductor detector coupled with a neutron converter is a good candidate for neutron detection, especially for its compactness and reliability if compared with other devices, such as {sup 3}He tubes, even though its intrinsic efficiency is rather lower. In this paper we show a neutron detector design consisting of a 3 cm Multiplication-Sign 3 cm silicon pad detector coupled with one or two external {sup 6}LiF layers, enriched in {sup 6}Li at 95%, placed in contact with the Si active surfaces. This prototype, first characterized and tested at INFN Laboratori Nazionali del Sud and then at JRC Ispra, was successfully shown to detect thermal neutrons with the expected efficiency and an outstanding gamma rejection capability.

Barbagallo, Massimo [Istituto Nazionale di Fisica Nucleare, Sezione di Bari (Italy); Cosentino, Luigi; Marchetta, Carmelo; Pappalardo, Alfio; Scire, Carlotta; Scire, Sergio; Schillaci, Maria; Vecchio, Gianfranco; Finocchiaro, Paolo [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy); Forcina, Vittorio; Peerani, Paolo [European Commission, Joint Research Centre, Institute of Transuranium Elements, Ispra (Italy); Vaccaro, Stefano [European Commission, Directorate-General for Energy (Luxembourg)

2013-03-15T23:59:59.000Z

425

MAGNETIC NEUTRON SCATTERING  

SciTech Connect

Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern science, ranging from large-scale structures and dynamics of polymers and biological systems, to electronic properties of today's technological materials. Neutron scattering developed into a vast field, encompassing many different experimental techniques aimed at exploring different aspects of matter's atomic structure and dynamics. Modern magnetic neutron scattering includes several specialized techniques designed for specific studies and/or particular classes of materials. Among these are magnetic reflectometry aimed at investigating surfaces, interfaces, and multilayers, small-angle scattering for the large-scale structures, such as a vortex lattice in a superconductor, and neutron spin-echo spectroscopy for glasses and polymers. Each of these techniques and many others offer exciting opportunities for examining magnetism and warrant extensive reviews, but the aim of this chapter is not to survey how different neutron-scattering methods are used to examine magnetic properties of different materials. Here, we concentrate on reviewing the basics of the magnetic neutron scattering, and on the recent developments in applying one of the oldest methods, the triple axis spectroscopy, that still is among the most extensively used ones. The developments discussed here are new and have not been coherently reviewed. Chapter 2 of this book reviews magnetic small-angle scattering, and modern techniques of neutron magnetic reflectometry are discussed in Chapter 3.

ZALIZNYAK,I.A.; LEE,S.H.

2004-07-30T23:59:59.000Z

426

Neutron Radii in Nuclei and the Neutron Equation of State  

Science Journals Connector (OSTI)

The root-mean-square radius for neutrons in nuclei is investigated in the Skyrme Hartree-Fock model. The main source of theoretical variation comes from the exchange part of the density-dependent interaction which can be related to a basic property of the neutron equation of state. A precise measurement of the neutron radius in 208Pb would place an important new constraint on the equation of state for neutron matter. The Friedman-Pandharipande neutron equation of state would lead to a very precise value of 0.16±0.02 fm for the difference between the neutron and the proton root-mean-square radius in 208Pb.

B. Alex Brown

2000-12-18T23:59:59.000Z

427

A high-fluence fusion neutron source  

SciTech Connect

A conceptual design of a D-T fusion facility for continuous production of 14-MeV neutron wall loading from 5 to 10 MW/m/sup 2/ at the plasma surface is presented. In this design, D-T neutrons are produced in a linear, two-component plasma formed by neutral beam irradiation of a fully ionized warm plasma target. The beam energy, which is deposited in the center, is transferred to the warm plasma mainly by electron drag and is conducted along the target plasma column to end regions where it is absorbed in neutral gas at high pressure. The target plasma is operated in a regime where electron thermal conduction along the column is the controlling energy-loss process. The loss rate is minimized by adjusting the diameter and length of the plasma column. A substantial gradient in T/sub e/ along the column results in recombination of the plasma to gas in the end-regions before impact on the end walls. The resultant hot gas is cooled by contact with large-area heat exchangers. In this way, the large steady-state heat load from the injected neutral beams is diffused and removed at tolerable heat flux levels. The reacting plasma is essentially an extrapolation of the 2XIIB high-..beta.. plasma to higher magnetic field, ion energy, and density. 12 refs., 4 figs.

Coensgen, F.H.; Casper, T.A.; Correll, D.L.; Damm, C.C.; Futch, A.H.; Logan, B.G.; Molvik, A.W.; Bulmer, R.H.

1988-02-17T23:59:59.000Z

428

Characterization of Dosimetry of the BMRR Horizontal Thimble Tubes and Broad Beam Facility.  

SciTech Connect

The Brookhaven Medical Research Reactor was a 5 mega-watt, light-water cooled and heavy-graphite moderated research facility. It has two shutter-equipped treatment rooms, three horizontally extended thimble tubes, and an ex-core broad beam facility. The three experimental thimbles, or activation ports, external to the reactor tank were designed for several uses, including the investigations on diagnostic and therapeutic methods using radioactive isotopes of very short half-life, the analysis of radiation exposure on tissue-equivalent materials using a collimated neutron beam, and the evaluation of dose effects on biological cells to improve medical treatment. At the broad beam facility where the distribution of thermal neutrons was essential uniform, a wide variety of mammalian whole-body exposures were studied using animals such as burros or mice. Also studied at the broad beam were whole-body phantom experiments, involving the use of a neutron or photon beam streaming through a screen to obtain the flux spectrum suitable for dose analysis on the sugar-urea-water mixture, a tissue-equivalent material. Calculations of the flux and the dose at beam ports based on Monte Carlo particle-transport code were performed, and measurements conducted at the same tally locations were made using bare or cadmium-covered gold foils. Analytical results, which show good agreement with measurement data, are presented in the paper.

Hu,J.P.; Reciniello, R.N.; Holden, N.E.

2008-05-05T23:59:59.000Z

429

Stable sonoluminescence within a water hammer tube  

Science Journals Connector (OSTI)

The sonoluminescence (SL) from the collapse of a single gas bubble within a liquid can be produced repetitively using an acoustic resonator. An alternative technique using a water hammer tube, producing SL from bubbles of greater size, is described here. A sealed vertical tube partly filled with a liquid and a gas at low pressure is subjected to vertical vibrations. The oscillation of the pressure within the liquid column, due to inertial forces, excites cavitation bubbles to grow and collapse. Rotation is used to confine the bubbles to the axis of the tube. Bright SL emissions were observed in a number of liquids. Repetitive emission was produced from bubbles in condensed phosphoric acid. Bubbles of 0.4mm ambient radius (containing 2×1014 xenon atoms) were excited by vibration at 35Hz. Approximately 1012 photons were emitted per collapse in the range 400–700nm (over four orders of magnitude greater than the brightest SL reported previously), corresponding to a 1% efficiency of the conversion of mechanical energy into light.

Avik Chakravarty; Theo Georghiou; Tacye E. Phillipson; Alan J. Walton

2004-06-24T23:59:59.000Z

430

Government Cuts Biofuels Targets  

Science Journals Connector (OSTI)

Government Cuts Biofuels Targets ... The Environmental Protection Agency has proposed lowering next year’s production targets for biofuels in the U.S. fuel mix—targets initially set in the Energy Independence & Security Act of 2007. ... Although the petroleum industry says the new targets still call for too much ethanol, biofuels advocates say changes to the Renewable Fuel Standard could kill the fledgling advanced biofuels industry. ...

MELODY BOMGARDNER; JEFF JOHNSON

2013-11-25T23:59:59.000Z

431

Neutron science research project in JAERI  

Science Journals Connector (OSTI)

A conception of Neutron Science Research Project (NSRP) has been proposed in Japan Atomic Energy Research Institute (JAERI) since 1994 for its future big science project. The project aims at exploring new basic science and nuclear energy science by using a high-intensity proton accelerator. NSRP is a complex composed of a powerful superconducting proton linac the target systems which convert the proton beam to neutrons or other particles and the facilities for scientific research programs. The proton linac is required to supply a high-intensity proton beam with an energy up to 1.5 GeV and an average current around 10 mA. The scientific research programs are as follows: In the area of basic science structural biology and material science with slow neutron scattering method neutron nuclear physics and spallation radioisotope physics and in the area of nuclear energy science the experimental feasibility studies of incineration for the nuclear waste transmutation and material developments with a neutron irradiation facility. Other scientific research programs are also proposed such as meson science for meson and muon physics radioisotope production for medical use. Research and development (R&D) have been carried out for the components of the injector system of the proton linac; an ion source an RFQ linac and a part of DTL linac. The conceptual design work and R&D activities for NSRP have started in the fiscal year 1996. The first beam of 1.5 GeV and 1 mA is expected to be extracted from the proton linac by 2004 and finally a 10 mA is to be obtained in 2007 by reflecting the results of technological developments.

Y. Suzuki; Y. Oyama; T. Sasa; K. Suzuki; H. Yasuda; T. Tone; T. Takizuka; M. Mizumoto; N. Watanabe; T. Mukaiyama

1997-01-01T23:59:59.000Z

432

Advanced Neutron Source (ANS) Project. Progress report FY 1993  

SciTech Connect

This report covers the progress made in 1993 in the following sections: (1) project management; (2) research and development; (3) design and (4) safety. The section on research and development covers the following: (1) reactor core development; (2) fuel development; (3) corrosion loop tests and analysis; (4) thermal-hydraulic loop tests; (5) reactor control and shutdown concepts; (6) critical and subcritical experiments; (7) material data, structure tests, and analysis; (8) cold source development; (9) beam tube, guide, and instrument development; (10) neutron transport and shielding; (11) I and C research and development; and (12) facility concepts.

Campbell, J.H. [ed.; Selby, D.L.; Harrington, R.M. [Oak Ridge National Lab., TN (United States); Thompson, P.B. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States). Engineering Div.

1994-01-01T23:59:59.000Z

433

Characterization of a novel, short pulse laser-driven neutron source  

SciTech Connect

We present a full characterization of a short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions of laser-driven ions deposited in a secondary target. The emission of neutrons is a superposition of an isotropic component into 4? and a forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux of 4.4 × 10{sup 9} neutrons/sr has been observed and used for fast neutron radiography. On-shot characterization of the ion driver and neutron beam has been done with a variety of different diagnostics, including particle detectors, nuclear reaction, and time-of-flight methods. The results are of great value for future optimization of this novel technique and implementation in advanced applications.

Jung, D.; Falk, K.; Guler, N.; Devlin, M.; Favalli, A.; Fernandez, J. C.; Gautier, D. C.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schoenberg, K.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wender, S. A.; Wilde, C. H.; Wurden, G. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Deppert, O. [Technische Universität Darmstadt, 64289 Darmstadt (Germany)] [Technische Universität Darmstadt, 64289 Darmstadt (Germany); and others

2013-05-15T23:59:59.000Z

434

High Power Cryogenic Targets  

SciTech Connect

The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

Gregory Smith

2011-08-01T23:59:59.000Z

435

Neutron-Neutron Scattering at Low Energies  

Science Journals Connector (OSTI)

This paper investigates the information contained in a neutron-neutron scattering experiment at low energies which could be performed by colliding beams coming from an underground nuclear explosion. The significance of such an experiment is discussed from the point of view of a check on charge symmetry and charge independence, and it is found that because of the electromagnetic complications in proton-proton scattering, and because of the proton-neutron mass difference, the knowledge of neutron-neutron scattering would be of considerable value. The functional form of the experimental data which is most convenient for analysis and the approximate relative magnitude of the terms is investigated, and it is concluded that for the kind of experiment which is envisaged (measuring cross sections to 10% from 20 keV to 2 MeV) only two parameters should be kept in the effective-range expansion. The connection between the number and distribution of energies at which the cross section is measured and the error on the individual measurements, on the one hand, and the accuracy of the effective-range parameters deduced from the experiments, on the other, is given explicitly and is found also to depend on the absolute magnitude of the scattering length. The results show that ten 10% measurements, suitably distributed between 20 keV and 2 MeV, can determine the sign of the scattering length to four standard deviations, the magnitude of the effective range to 50-70%, and the magnitude of the scattering length to about 3%. Finally, the relationship between the variation of the effective-range parameters and the corresponding variation in the parameters of the scattering potential is studied, and it is found that, while this relationship is strongly shape-dependent, a small change in the potential parameters, in any case, results in a large change in the scattering length, but a small one in the effective range. Numerical relationships show that, even in the worst case, the variation in the scattering length is about eight times the variation in the potential parameter. It is concluded that a 10% experiment at 20 energies between 20 keV and 2 MeV would be able to get information on the potential parameters sufficiently accurately so that charge-dependent or charge-symmetry violating effects could be detected.

Michael J. Moravcsik

1964-11-09T23:59:59.000Z

436

Time-reversal invariance violation measurement using polarized neutron scattering from polarized xenon  

E-Print Network (OSTI)

We proposed to use polarized neutrons scattering from a hyperpolarized 131Xe gaseous target in order to measure time-reversal violation effect in baryon processes with nucleons. This article provides a brief introduction, historical review, and possible methods to construct a hyperpolarized 131Xe gaseous target.

Pinghan Chu

2014-03-06T23:59:59.000Z

437

Segmented lasing tube for high temperature laser assembly  

DOE Patents (OSTI)

A high temperature laser assembly capable of withstanding operating temperatures in excess of 1500.degree. C. is described comprising a segmented cylindrical ceramic lasing tube having a plurality of cylindrical ceramic lasing tube segments of the same inner and outer diameters non-rigidly joined together in axial alignment; insulation of uniform thickness surround the walls of the ceramic lasing tube; a ceramic casing, preferably of quartz, surrounding the insulation; and a fluid cooled metal jacket surrounds the ceramic casing. In a preferred embodiment, the inner surface of each of the ceramic lasing tube segments are provided with a pair of oppositely spaced grooves in the wall thereof parallel to the center axis of the segmented cylindrical ceramic lasing tube, and both of the grooves and the center axis of the segmented cylindrical ceramic lasing tube lie in a common plane, with the grooves in each ceramic lasing tube segment in circumferential alignment with the grooves in the adjoining ceramic lasing tube segments; and one or more ceramic plates, all lying in a common plane to one another and with the central axis of the segmented ceramic lasing tube, are received in the grooves to provide additional wall area in the segmented ceramic lasing tube for collision and return to ground state of metastable metal atoms within the segmented ceramic lasing tube.

Sawicki, Richard H. (Danville, CA); Alger, Terry W. (Tracy, CA); Finucane, Raymond G. (Pleasanton, CA); Hall, Jerome P. (Livermore, CA)

1996-01-01T23:59:59.000Z

438

Guided wave acoustic monitoring of corrosion in recovery boiler tubing  

SciTech Connect

Corrosion of tubing used in black-liquor recovery boilers is a major concern in all pulp and paper mills. Extensive corrosion in recovery boiler tubes can result in a significant safety and environmental hazard. Considerable plant resources are expended to inspect recovery boiler tubing. Currently, visual and ultrasonic inspections are primarily used during the annual maintenance shutdown to monitor corrosion rates and cracking of tubing. This Department of Energy, Office of Industrial Technologies project is developing guided acoustic waves for use on recovery boiler tubing. The feature of this acoustic technique is its cost-effectiveness in inspecting long lengths of tubes from a single inspection point. A piezoelectric or electromagnetic transducer induces guided waves into the tubes. The transducer detects fireside defects from the coldside or fireside of the tube. Cracking and thinning on recovery boiler tubes have been detected with this technique in both laboratory and field applications. This technique appears very promising for recovery boiler tube application, potentially expediting annual inspection of tube integrity.

Quarry, M J; Chinn, D J

2004-02-19T23:59:59.000Z

439

Single-tube thermal and hydraulic tube support test. Volume 2. Appendixes. Final report  

SciTech Connect

The work described in this report (volumes 1 and 2) was an experimental project to measure the inception and extent of dryout or liquid deficient heat transfer and chemical precipitation in presently used steam generator tube-tube support geometries and modified geometries. Since chemical precipitation or concentration may lead to corrosion, this program was planned to find the dependence of dryout and chemical precipitation on geometry, heat flux and fluid conditions. It was found that dryout depended principally on tube support geometry and heat flux. There was little dependence on flow rate, quality and pressure. It was found that certain tube support geometries could produce local dryout which in turn could permit significant chemical concentration. Chemical concentration was not found in the tube support geometries not exhibiting dryout. The interrelationship between the heat and mass transfer processes in the crevices was further demonstrated by comparing the results of an analytic model for predicting the shape of the liquid-vapor interface to the outline of a precipitate pattern resulting from chemical concentration.

Curlee, N.J. Jr.; Baum, A.J.

1981-09-01T23:59:59.000Z

440

Single-tube thermal and hydraulic tube support test. Final report  

SciTech Connect

The work described in this report (volumes 1 and 2) was an experimental project to measure the inception and extent of dryout or liquid deficient heat transfer and chemical precipitation in presently used steam generator tube-tube support geometries and modified geometries. Since chemical precipitation or concentration may lead to corrosion this program was planned to find the dependence of dryout and chemical precipitation on geometry, heat flux and fluid conditions. It was found that dryout depended principally on tube support geometry and heat flux. There was little dependence on flow rate, quality and pressure. It was found that certain tube support geometries could produce local dryout which in turn could permit significant chemical concentration. Chemical concentration was not found in tube support geometries not exhibiting dryout. The interrelationship between the heat and mass transfer processes in the crevices was further demonstrated by comparing the results of an analytic model for predicting the shape of the liquid vapor interface to the outline of a precipitate pattern resulting from chemical concentration.

Curlee, N.J. Jr.; Baum, A.J.

1981-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

NEUTRON RADIOGRAPHY (NRAD) REACTOR 64-ELEMENT CORE UPGRADE  

SciTech Connect

The neutron radiography (NRAD) reactor is a 250 kW TRIGA (registered) (Training, Research, Isotopes, General Atomics) Mark II , tank-type research reactor currently located in the basement, below the main hot cell, of the Hot Fuel Examination Facility (HFEF) at the Idaho National Laboratory (INL). It is equipped with two beam tubes with separate radiography stations for the performance of neutron radiography irradiation on small test components. The interim critical configuration developed during the core upgrade, which contains only 62 fuel elements, has been evaluated as an acceptable benchmark experiment. The final 64-fuel-element operational core configuration of the NRAD LEU TRIGA reactor has also been evaluated as an acceptable benchmark experiment. Calculated eigenvalues differ significantly (approximately +/-1%) from the benchmark eigenvalue and have demonstrated sensitivity to the thermal scattering treatment of hydrogen in the U-Er-Zr-H fuel.

John D. Bess

2014-03-01T23:59:59.000Z

442

Neutron degeneracy and plasma physics effects on radiative neutron captures in neutron star crust  

Science Journals Connector (OSTI)

We consider the astrophysical reaction rates for radiative neutron capture reactions (n,?) in the crust of a neutron star. The presence of degenerate neutrons at high densities (mainly in the inner crust) can drastically affect the reaction rates. Standard rates assuming a Maxwell-Boltzmann distribution for neutrons can underestimate the rates by several orders of magnitude. We derive simple analytical expressions for reaction rates at a variety of conditions with account for neutron degeneracy. We also discuss the plasma effects on the outgoing radiative transition channel in neutron radiative capture reactions and show that these effects can also increase the reaction rates by a few orders of magnitude. In addition, using detailed balance, we analyze the effects of neutron degeneracy and plasma physics on reverse (?,n) photodisintegration. We discuss the dependence of the reaction rates on temperature and neutron chemical potential and outline the efficiency of these reactions in the neutron star crust.

P. S. Shternin; M. Beard; M. Wiescher; D. G. Yakovlev

2012-07-24T23:59:59.000Z

443

Measurements Of Spin Observables In Pseudoscalar-Meson Photo-Production Using Polarized Neutrons In Solid HD  

SciTech Connect

Psuedo-scalar meson photo production measurements have been carried out with longitudinally-polarized neutrons using the circularly and linearly polarized photon beams and the CLAS at Thomas Jefferson National Accelerator Facility (Jlab). The experiment aims to obtain a complete set of spin observables on an efficient neutron target. Preliminary E asymmetries for the exclusive reaction, gamma + n(p)--> pi- + p(p), selecting quasi free neutron kinematics are discussed.

Kageya, Tsuneo

2014-01-01T23:59:59.000Z

444

Neutron lifetime measurements using gravitationally trapped ultracold neutrons  

E-Print Network (OSTI)

Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before:the probability of UCN losses from the trap was only 1% of that for neutron beta decay. The neutron lifetime obtained,878.5+/-0.7stat+/-0.3sys s, is the most accurate experimental measurement to date.

A. P. Serebrov; V. E. Varlamov; A. G. Kharitonov; A. K. Fomin; Yu. N. Pokotilovski; P. Geltenbort; I. A. Krasnoschekova; M. S. Lasakov; R. R. Taldaev; A. V. Vassiljev; O. M. Zherebtsov

2007-02-06T23:59:59.000Z

445

Novel neutron focusing mirrors for compact neutron sources  

E-Print Network (OSTI)

We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. ...

Gubarev, M.V.

446

Neutron skin of nuclei near the neutron drip line  

Science Journals Connector (OSTI)

Performing Skyrme-type deformed Hartree-Fock calculations, the possible presence of neutron skin in nuclei towards neutron drip line is studied. The thickness of the neutron skin is found to be nearly constant in all directions if it is measured perpendicular to the surface, and in a given nucleus the number of neutrons being inside of the neutron skin is almost independent of the deformation (namely, spherical shape or normal deformation or superdeformation). In the region of medium-heavy nuclei our calculation shows the presence of a series of neutron-rich nuclei, in which a neutron skin is present and yet the neutron one-particle spectra are far from those in a harmonic oscillator (plus spin-orbit) potential.

I. Hamamoto and X. Z. Zhang

1995-11-01T23:59:59.000Z

447

Neutron lifetime measurements using gravitationally trapped ultracold neutrons  

SciTech Connect

Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before: the probability of UCN losses from the trap was only 1% of that for neutron {beta} decay. The neutron lifetime obtained, 878.5{+-}0.7{sub stat}{+-}0.3{sub sys} s, is the most accurate experimental measurement to date.

Serebrov, A. P.; Varlamov, V. E.; Kharitonov, A. G.; Fomin, A. K.; Krasnoschekova, I. A.; Lasakov, M. S.; Taldaev, R. R.; Vassiljev, A. V.; Zherebtsov, O. M. [Petersburg Nuclear Physics Institute, Russian Academy of Sciences, RU-188300 Gatchina, Leningrad District (Russian Federation); Pokotilovski, Yu. N. [Joint Institute for Nuclear Research, RU-141980 Dubna, Moscow Region (Russian Federation); Geltenbort, P. [Institut Max von Laue Paul Langevin, Boite Postal 156, F-38042 Grenoble Cedex 9 (France)

2008-09-15T23:59:59.000Z

448

Neutron Scattering Instrumentation for Biology at Spallation Neutron Sources  

Science Journals Connector (OSTI)

Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. ... fact, the curre...

Roger Pynn

1996-01-01T23:59:59.000Z

449

Electron-neutron scattering and transport properties of neutron stars  

E-Print Network (OSTI)

We show that electrons can couple to the neutron excitations in neutron stars and find that this can limit their contribution to the transport properties of dense matter, especially the shear viscosity. The coupling between electrons and neutrons is induced by protons in the core, and by ions in the crust. We calculate the effective electron-neutron interaction for the kinematics of relevance to the scattering of degenerate electrons at high density. We use this interaction to calculate the electron thermal conductivity, electrical conductivity, and shear viscosity in the neutron star inner crust, and in the core where we consider both normal and superfluid phases of neutron-rich matter. In some cases, particularly when protons are superconducting and neutrons are in their normal phase, we find that electron-neutron scattering can be more important than the other scattering mechanisms considered previously.

Bertoni, Bridget; Rrapaj, Ermal

2014-01-01T23:59:59.000Z

450

Observation of ionization fronts in low density foam targets  

SciTech Connect

Ionization fronts have been observed in low density chlorinated foam targets and low density foams confined in gold tubes using time resolved {ital K}-shell absorption spectroscopy. The front was driven by an intense pulse of soft x-rays produced by high power laser irradiation. The density and temperature profiles inferred from the radiographs provided detailed measurement of the conditions. The experimental data were compared to radiation hydrodynamics simulations and reasonable agreement was obtained. {copyright} {ital 1999 American Institute of Physics.}

Hoarty, D. [Imperial College of Science, Technology and Medicine, London (United Kingdom)] [Imperial College of Science, Technology and Medicine, London (United Kingdom); [Radiation Physics Department, AWE Aldermaston, Reading, Berkshire (United Kingdom); Willi, O.; Barringer, L.; Vickers, C. [Imperial College of Science, Technology and Medicine, London (United Kingdom)] [Imperial College of Science, Technology and Medicine, London (United Kingdom); Watt, R. [P24, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [P24, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Nazarov, W. [Chemistry Department, University of Dundee (United Kingdom)] [Chemistry Department, University of Dundee (United Kingdom)

1999-05-01T23:59:59.000Z

451

Physics Analyses in the Design of the HFIR Cold Neutron Source  

SciTech Connect

Physics analyses have been performed to characterize the performance of the cold neutron source to be installed in the High Flux Isotope Reactor at the Oak Ridge National Laboratory in the near future. This paper provides a description of the physics models developed, and the resulting analyses that have been performed to support the design of the cold source. These analyses have provided important parametric performance information, such as cold neutron brightness down the beam tube and the various component heat loads, that have been used to develop the reference cold source concept.

Bucholz, J.A.

1999-09-27T23:59:59.000Z

452

The neutron identified: Sir James Chadwick  

Science Journals Connector (OSTI)

The neutron identified: Sir James Chadwick ... Uses source material to describe the discovery of the neutron by James Chadwick. ...

Alfred B. Garrett

1962-01-01T23:59:59.000Z

453

Portable Neutron Sensors for Emergency Response Operations  

SciTech Connect

This slide-show presents neutron measurement work, including design, use and performance of different neutron detection systems.

Mukhopadhyay, S., Maurer, R., Detweiler, R.

2012-06-22T23:59:59.000Z

454

Neutron scattering above 25 MeV with monoenergetic neutrons  

Science Journals Connector (OSTI)

Technical problems encountered in measuring elastic and inelastic neutron scattering at kinetic energies well above 25 MeV are considered by extrapolating from experience with lower energy neutrons. It is concluded that all of the techniques required for a high?quality systematic study of neutron scattering—with the notable exception of a suitable accelerator facility—are at hand.

Roger W. Finlay

1985-01-01T23:59:59.000Z

455

Sandia Neutron Detector Is Based on Polyacetylene  

Science Journals Connector (OSTI)

Sandia Neutron Detector Is Based on Polyacetylene ... It also might form the basis of an electrically readable dosimeter that records neutron flux (measured as neutrons per square centimeter) as well as a detector that could provide a cross-sectional image of neutron flux with high spatial resolution. ... Hence, most neutron detectors use a converter material that converts the neutrons to charged particles. ...

RUDY BAUM

1987-02-09T23:59:59.000Z

456

Neutron Science | More Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

ORNL's long history of neutron science began in the 1940s with the pioneering neutron scattering studies of Ernest Wollan and Clifford Shull. Shull was co-recipient of...

457

High flux compact neutron generators  

E-Print Network (OSTI)

High Flux Compact Neutron Generators ‡ J. Reijonen §,1 , T-Compact high flux neutron generators are developed at thevoltage feed through of the generator is shown in Fig. 4.

Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

2001-01-01T23:59:59.000Z

458

Neutron Scattering Conference Archive  

NLE Websites -- All DOE Office Websites (Extended Search)

Conference Archive Conference Archive A new portal for neutron scattering has just been established at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for archival purposes but no new content will be added. We encourage everyone interested in neutron scattering to take full advantage of this exciting new resource for our community. Neutronsources.org 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 2000 June 12-14, 2000 Workshop on "New Opportunities for Better User Group Software (NOBUGS III)" Location Daresbury Laboratory, Cheshire, UK Contact Mark Enderby, Daresbury Laboratory Email M.J.Enderby@dl.ac.uk URL http://nobugs.dl.ac.uk/

459

Contacts | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Points of Contact Science Points of Contact Name Research Area Doug Abernathy Wide Angular-Range Chopper Spectrometer (ARCS). Atomic-scale dynamics at thermal and epithermal energies Ke An Engineering Materials Diffractometer (VULCAN). Residual stress, deformation mechanism of materials, phase transitions/transformation, and in situ/operando neutron diffraction in material systems (e.g., working batteries). John Ankner Liquids Reflectometer (LR). Density profiles normal to the surface at liquid surfaces and liquid interfaces Bryan Chakoumakos Nuclear and magnetic crystal structure systematics and structure-property relationships among inorganic materials, powder and single-crystal neutron and x-ray diffraction methods Leighton Coates Macromolecular Neutron Diffractometer (MaNDi). Protein crystallography, biological structure and function

460

Personnel electronic neutron dosimeter  

DOE Patents (OSTI)

A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

Falk, Roger B. (Lafayette, CO); Tyree, William H. (Boulder, CO)

1984-12-18T23:59:59.000Z

Note: This page contains sample records for the topic "neutron tube target" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Personnel electronic neutron dosimeter  

DOE Patents (OSTI)

A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

Falk, R.B.; Tyree, W.H.

1982-03-03T23:59:59.000Z

462

Cooling of neutron stars  

Science Journals Connector (OSTI)

On the basis of current physical understanding, it is impossible to predict with confidence the interior constitution of neutron stars. Cooling of neutron stars provides a possible way of discriminating among possible states of matter within them. In the standard picture of cooling by neutrino emission developed over the past quarter of a century, neutron stars are expected to cool relatively slowly if their cores are made up of nucleons, and to cool faster if matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been called into question by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.

C. J. Pethick

1992-10-01T23:59:59.000Z

463

Flow mapping for an ESS horizontal target  

SciTech Connect

In the target of the European spallation neutron source (ESS), the beam line is horizontal and the mercury is fully forced by a pump in a parallel channel geometry. The top front of the assembly is a hemicylindrical wall, where the beam enters and is thus called a window. The main body is partitioned by a horizontal separation plate into the upper and the lower flow channels. The target liquid flows in the lower channel to the window region, turns there, and flows out in the upper channel. A thermal-hydraulic study is under way to investigate the general behavior of the flow in this configuration. The present experimental work is the first step of an effort to validate computer codes. The model used in this investigation is two-dimensional and uses water.

Takeda, Y.; Kikura, H.; Taishi, T. [Paul Scherrer Institute, Villigen (Switzerland)

1997-12-01T23:59:59.000Z

464

Corrosion resistant neutron absorbing coatings  

DOE Patents (OSTI)

A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

Choi, Jor-Shan (El Cerrito, CA); Farmer, Joseph C. (Tracy, CA); Lee, Chuck K. (Hayward, CA); Walker, Jeffrey (Gaithersburg, MD); Russell, Paige (Las Vegas, NV); Kirkwood, Jon (Saint Leonard, MD); Yang, Nancy (Lafayette, CA); Champagne, Victor (Oxford, PA)

2012-05-29T23:59:59.000Z

465

Corrosion resistant neutron absorbing coatings  

DOE Patents (OSTI)

A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

2013-11-12T23:59:59.000Z

466

Passive Neutron Detection at Borders  

SciTech Connect

Radiation portal monitor systems have been deployed to screen for illicit trafficking of radioactive materials at international border crossings. This report reviews some of the neutron detection requirements and capabilities of passive detection systems used for such applications. Simulations show the effects of cargo materials on neutron spectra, different detector geometries, using a large-array of neutron detectors, and the effects of backgrounds including “ship effect” neutrons.

Kouzes, Richard T.; Siciliano, Edward R.; Ely, James H.; Keller, Paul E.; McConn, Ronald J.

2008-03-01T23:59:59.000Z

467

Thermal Neutron Capture y's (CapGam)  

DOE Data Explorer (OSTI)

The National Nuclear Data Center (NNDC) presents two tables showing energy and photon intensity with uncertainties of gamma rays as seen in thermal-neutron capture.  One table is organized in ascending order of gamma energy, and the second is organized by Z, A of the target. In the energy-ordered table the three strongest transitions are indicated in each case. The nuclide given is the target nucleus in the capture reaction. The gamma energies given are in keV. The gamma intensities given are relative to 100 for the strongest transition. %I? (per 100 n-captures) for the strongest transition is given, where known. All data are taken from the Evaluated Nuclear Structure Data File (ENSDF), a computer file of evaluated nuclear structure data and from the eXperimental Unevaluated Nuclear Data List (XUNDL). (Specialized Interface)

468

Effects of grids in drift tubes  

SciTech Connect

In 2011, we upgraded a 201 MHz buncher in the proton injector for the alternating gradient synchrotron (AGS) - relativistic heavy ion collider (RHIC) complex. In the buncher we installed four grids made of tungsten to improve the transit time factor. The grid installed drift tubes have 32 mm of inner diameter and the each grid consists of four quadrants. The quadrants were cut out precisely from 1mm thick tungsten plates by a computerized numerically controlled (CNC) wire cutting electrical discharge machining (EDM). The 3D electric field of the grid was simulated.

Okamura M.; Yamauchi, H.

2012-05-20T23:59:59.000Z

469

Drift Tube Linac Conditioning of Tank1  

E-Print Network (OSTI)

Tank1 of the Drift Tube Linac (DTL) of the Linac4 has been conditioned at the Linac4 tunnel. The tank was tuned for resonance at 352.2 MHz, and stable operation has been achieved with 725 µs long RF pulses at a repetition rate of 1 Hz. The maximum RF level that has been reached is 810 kW with a pulse width of 600 µs. Since this was the first RF structure exclusively conditioned in the Linac4 tunnel with the operation and control software of Linac4, some related issues and limitations had to be taken into account.

Shafqat, N; Toor, W A

2014-01-01T23:59:59.000Z

470

Sound Coiled-Tubing Drilling Practices  

SciTech Connect

This Coiled-Tubing Drilling (CTD) Sound Practices Manual provides tools needed by CTD engineers and supervisors to plan, design and perform safe, successful CTD operations. As emphasized throughout, both careful planning and attention to detail are mandatory for success. A bibliography of many useful CTD references is presented in Chapter 6. This manual is organized according to three processes: 1) Pre-Job Planning Process, 2) Operations Execution Process, and 3) Post-Job Review Process. Each is discussed in a logical and sequential format.

Williams, Thomas; Deskins, Greg (Maurer Technology Inc.); Ward, Stephen L. (Advantage Energy Services Ltd); Hightower, Mel

2001-09-30T23:59:59.000Z

471

Neutron phase echo  

Science Journals Connector (OSTI)

The coherent overlap of the waves traversing the two legs of a perfect-crystal neutron interferometer is altered by a material with a neutron-nuclear optical potential. The fringe visibility is limited by the longitudinal coherence length. The loss of interference contrast caused by a slab of material of positive optical potential can be restored by placing another slab of material with a negative optical potential in the same leg of the interferometer. This paper describes the observation and detailed characterization of this quantum-mechanical phenomenon, which we call the phase-echo effect.

R. Clothier; H. Kaiser; S. A. Werner; H. Rauch; H. Wölwitsch

1991-11-01T23:59:59.000Z

472

Inelastic Neutron Scattering Instrumentation  

Science Journals Connector (OSTI)

Abstract Inelastic neutron scattering spectroscopy spans an enormous energy range, which is equivalent to a wide range of timescales. It is convenient to divide the whole energy range into three sectors, while recognising that there is significant overlap between them. In the lowest energy range, ± 10 meV the applications are principally quasielastic scattering and tunneling spectroscopy. The second range, 0–1000 meV covers the regions of vibrational spectroscopy and magnetic excitations. The highest range above 1000 meV is the province of neutron Compton scattering. The instrumentation used in each of these energy regimes is described.

S.F. Parker

2014-01-01T23:59:59.000Z

473

Neutron Bombardment of Counting Diamonds  

Science Journals Connector (OSTI)

21 February 1956 research-article Neutron Bombardment of Counting Diamonds A. H...Examination was also made of the effect of neutron bombardment on pulse-height distribution...additional charge traps produced by the neutrons. The layered crystal texture disclosed...

1956-01-01T23:59:59.000Z

474

NOTES ON NEUTRON DEPTH PROFILING  

E-Print Network (OSTI)

NOTES ON NEUTRON DEPTH PROFILING by J.K. Shultis Department of Mechanical and Nuclear Engineering College of Engineering Kansas State University Manhattan, Kansas 66506 Dec. 2003 #12;Notes on Neutron Depth Profiling J. Kenneth Shultis December 2003 1 Introduction The purpose of neutron depth profiling

Shultis, J. Kenneth

475

Pollen Tubes Lacking a Pair of K+ Transporters Fail to Target Ovules in Arabidopsis  

Science Journals Connector (OSTI)

...chx21 +/) 1:1 62:54 a WTi chx21-2 chx23-4+/ chx23...chx23 +/) 1:1 60:53 a WTi chx21-2+/ chx23-4 chx21...chx23 3:5:2 Hygr 28:63:23 a WTi refers to a male-sterile mutant (At5g42650...

Yongxian Lu; Salil Chanroj; Lalu Zulkifli; Mark A. Johnson; Nobuyuki Uozumi; Alice Cheung; Heven Sze

2011-01-14T23:59:59.000Z

476

Neutron - Mirror Neutron Oscillations: How Fast Might They Be?  

E-Print Network (OSTI)

We discuss the phenomenological implications of the neutron (n) oscillation into the mirror neutron (n'), a hypothetical particle exactly degenerate in mass with the neutron but sterile to normal matter. We show that the present experimental data allow a maximal n-n' oscillation in vacuum with a characteristic time $\\tau$ much shorter than the neutron lifetime, in fact as small as 1 sec. This phenomenon may manifest in neutron disappearance and regeneration experiments perfectly accessible to present experimental capabilities and may also have interesting astrophysical consequences, in particular for the propagation of ultra high energy cosmic rays.

Zurab Berezhiani; Luis Bento

2005-07-03T23:59:59.000Z

477

Scission neutron emission and prompt fission neutron spectrum  

E-Print Network (OSTI)

The mass, energy and angular integrated spectra of prompt fission neutrons for sup 2 sup 3 sup 5 U induced fission in the energy range from thermal to 5 MeV were analyzed. It allows assume that about 0.362+-0.025 neutrons per fission are emitted due to another mechanism then neutron emission from excited fragments after full acceleration. The spectrum of scission neutrons consists of two components with average energy 0.98 MeV and 2.74 MeV. The share of scission neutrons and their spectrum shape estimated in this work does not contradict to results of differential experiments analyzed in previous papers.

Kornilov, N V

2001-01-01T23:59:59.000Z

478

Neutron-halo nuclei in cold synthesis and cluster decay of heavy nuclei: Z=104 nucleus as an example  

Science Journals Connector (OSTI)

Nuclei at the neutron-drip line are studied. The light neutron-halo nuclei are found to play an important role for both cold fusion reactions and exotic cluster decay studies of heavy nuclei at the neutron-drip line. For cold fusion reactions, beams of neutron-halo nuclei are shown to occur as natural extensions of the conventional lighter beams but with the corresponding target nuclei as the heavy neutron-rich radioactive nuclei. Thus, in synthesizing the various isotopes of a neutron-rich cool compound