Recent performance and ignition tests of the pulsed SNS H{sup −} source for 1-MW neutron production

Han, B. X.; Murray, S. N.; Pennisi, T. R.; Piller, C.; Santana, M.; Welton, R. F.

doi:10.1063/1.4916428

Title: Recent performance and ignition tests of the pulsed SNS H{sup −} source for 1-MW neutron production

Full Record
Other Related Research

Abstract

After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H{sup −} beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ∼0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H{sup −} beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation. At the request of the authors and the Proceedings Editor this article has been updated to include References 3–13, which were present in the author’s original submissionmore »« less

Authors:

Han, B. X.; Murray, S. N.; Pennisi, T. R.; Piller, C.; Santana, M.; Welton, R. F. ^[1]

Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.A (United States)

Publication Date:: Wed Apr 08 00:00:00 EDT 2015

OSTI Identifier:: 22391410

Resource Type:: Journal Article

Journal Name:: AIP Conference Proceedings

Additional Journal Information:: Journal Volume: 1655; Journal Issue: 1; Conference: NIBS 2014: 4. International Symposium on Negative Ions, Beams and Sources, Garching (Germany), 6-10 Oct 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X

Country of Publication:: United States

Language:: English

Subject:: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BEAM PULSERS; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; ELECTRONS; HYDROGEN; MHZ RANGE; NEUTRON SOURCES; NEUTRONS; OPERATION; OUTAGES; PERFORMANCE; PLASMA; SPALLATION; YIELDS

Citation Formats


                    Stockli, Martin P., E-mail: stockli@ornl.gov, Han, B. X., Murray, S. N., Pennisi, T. R., Piller, C., Santana, M., and Welton, R. F. Recent performance and ignition tests of the pulsed SNS H{sup −} source for 1-MW neutron production.  United States: N. p., 2015. 
        Web.  doi:10.1063/1.4916428.

Copy to clipboard


                    Stockli, Martin P., E-mail: stockli@ornl.gov, Han, B. X., Murray, S. N., Pennisi, T. R., Piller, C., Santana, M., & Welton, R. F. Recent performance and ignition tests of the pulsed SNS H{sup −} source for 1-MW neutron production.  United States.  https://doi.org/10.1063/1.4916428

Copy to clipboard


                    Stockli, Martin P., E-mail: stockli@ornl.gov, Han, B. X., Murray, S. N., Pennisi, T. R., Piller, C., Santana, M., and Welton, R. F. 2015.  
        "Recent performance and ignition tests of the pulsed SNS H{sup −} source for 1-MW neutron production".  United States.  https://doi.org/10.1063/1.4916428.

Copy to clipboard


                    
@article{osti_22391410,

  title        = {Recent performance and ignition tests of the pulsed SNS H{sup −} source for 1-MW neutron production},

  author       = {Stockli, Martin P., E-mail: stockli@ornl.gov and Han, B. X. and Murray, S. N. and Pennisi, T. R. and Piller, C. and Santana, M. and Welton, R. F.},

  abstractNote = {After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H{sup −} beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ∼0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H{sup −} beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation. At the request of the authors and the Proceedings Editor this article has been updated to include References 3–13, which were present in the author’s original submission but were lost during manuscript processing in the Proceedings Editor's office. The updated article was published on 5 May 2015.},

  doi          = {10.1063/1.4916428},

  url          = {https://www.osti.gov/biblio/22391410},
  journal      = {AIP Conference Proceedings},

  issn         = {0094-243X},

  number       = 1,

  volume       = 1655,

  place        = {United States},

  year         = {Wed Apr 08 00:00:00 EDT 2015},

  month        = {Wed Apr 08 00:00:00 EDT 2015}

}

Copy to clipboard

Journal Article:

https://doi.org/10.1063/1.4916428

Other availability

Find in Google Scholar

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Recent Performance and Ignition Tests of the pulsed SNS H- Source for 1-MW Neutron Production

Conference Stockli, Martin; Han, Baoxi; Murray, Jr, S; ...

After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H- beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ~0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RFmore »« less
Full Text Available
Recent performance of and plasma outage studies with the SNS H{sup −} source

Journal Article Han, B.; Murray, S.; Pennisi, T.; ... - Review of Scientific Instruments

Spallation Neutron Source ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised radio frequency quadrupole (RFQ), which requires higher radio frequency power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H{sup −} beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ∼55-kW 2-MHz plasma pulses reflecting ∼90% of the continuousmore »« less
https://doi.org/10.1063/1.4935640
Ramping up the Spallation Neutron Source beam power with the H{sup -} source using 0 mg Cs/day

Journal Article Stockli, M; Han, B; Murray, S; ... - Review of Scientific Instruments

This paper describes the ramp up of the beam power for the Spallation Neutron Source by ramping up the pulse length, the repetition rate, and the beam current emerging from the H{sup -} source. Starting out with low repetition rates ({<=}10 Hz) and short pulse lengths ({<=}0.2 ms), the H{sup -} source and low-energy beam transport delivered from Lawrence Berkeley National Laboratory exceeded the requirements with almost perfect availability. This paper discusses the modifications that were required to exceed 0.2 ms pulse length and 0.2% duty factor with acceptable availability and performance. Currently, the source is supporting neutron production atmore »« less
https://doi.org/10.1063/1.3325085
Ramping up the SNS Beam Power with the H- Source using 0 mg Cs/Day

Conference Stockli, Martin; Han, Baoxi; Murray, Jr, S; ...

This paper describes the ramp up of the beam power for the Spallation Neutron Source by ramping up the pulse length, the repetition rate, and the beam current emerging from the H- source. Starting out with low rep rates (<10 Hz) and short pulse lengths (<<0.3 ms) the H- source and LEBT delivered from LBNL exceeded the requirements with almost perfect availability. This paper discusses the modifications that were required to exceed 0.2 ms pulse length and 0.2% duty factor with acceptable availability and performance. Currently the source is supporting neutron production at 1 MW with 38 mA LINAC beammore »« less
A New Plasma Radar Concept for Simultaneous Magnetic and Density Measurements

Technical Report Peebles, William; Crocker, Neal

An innovative, compact 288GHz interferometer has been fabricated, tested, installed and successfully demonstrated on the LAPD-U magnetized plasma at UCLA. The system takes advantage of frequency modulated (FM) radar techniques to deliver a compact heterodyne system. In addition, the reflected power from the source is taken advantage of to eliminate the need for additional quasi-optical components. Electron density in LAPD-U plasma has recently been increased substantially thereby requiring a higher frequency/shorter wavelength interferometer to avoid deleterious refractive effects. This system satisfies those needs. The system uses a 96GHz varactor tuned Gunn oscillator which passes to a passive tripler. This triplermore »« less
https://doi.org/10.2172/1898130

Full Text Available

Similar Records