skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Searching for Rare Decay Modes in the Reaction 238U+4He (40 MeV)

Abstract

In the present paper we describe an experiment performed on the reaction 238U + 4He (40 MeV) using a two-arm TOF-E (time-of-flight vs. energy) spectrometer with micro- channel plate detectors and mosaics of PIN diodes. This experiment has aimed at searching for fine structures in the total kinetic energy vs. fragment mass (TKE - M) distributions of binary events, and disclosing rare ternary decay modes others than already known from ternary fission. Details of the procedures of data handling are briefly described as well.

Authors:
;  [1]; ; ; ;  [2];  [3]; ; ; ; ; ;  [4]; ;  [5]
  1. Moscow Engineering Physics Institute, Moscow (Russian Federation)
  2. Department of Physics of University of Jyvaeskylae (Finland)
  3. University of Technology, Darmstadt (Germany)
  4. Joint Institute for Nuclear Research, Dubna (Russian Federation)
  5. V.G. Khlopin Radium Institute, St.-Petersburg (Russian Federation)
Publication Date:
OSTI Identifier:
21061795
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 912; Journal Issue: 1; Conference: International symposium on exotic nuclei, Khanty-Mansiysk (Russian Federation), 17-22 Jul 2006; Other Information: DOI: 10.1063/1.2746590; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALPHA REACTIONS; FINE STRUCTURE; KINETIC ENERGY; MASS DISTRIBUTION; MEV RANGE; NUCLEAR DECAY; NUCLEAR FRAGMENTATION; NUCLEAR FRAGMENTS; TERNARY FISSION; TIME-OF-FLIGHT MASS SPECTROMETERS; TIME-OF-FLIGHT METHOD; URANIUM 238 TARGET

Citation Formats

Pyatkov, Yu., Lavrova, J., Trzaska, W., Yamaletdinov, S., Lyapin, V., Sillanpaeae, M., Mutterer, M., Tjukavkin, A., Bolgov, D., Kamanin, D., Kopach, Yu., Kuznetsova, E., Tishchenko, V., Khlebnikov, S., and Tyurin, G.. Searching for Rare Decay Modes in the Reaction 238U+4He (40 MeV). United States: N. p., 2007. Web. doi:10.1063/1.2746590.
Pyatkov, Yu., Lavrova, J., Trzaska, W., Yamaletdinov, S., Lyapin, V., Sillanpaeae, M., Mutterer, M., Tjukavkin, A., Bolgov, D., Kamanin, D., Kopach, Yu., Kuznetsova, E., Tishchenko, V., Khlebnikov, S., & Tyurin, G.. Searching for Rare Decay Modes in the Reaction 238U+4He (40 MeV). United States. doi:10.1063/1.2746590.
Pyatkov, Yu., Lavrova, J., Trzaska, W., Yamaletdinov, S., Lyapin, V., Sillanpaeae, M., Mutterer, M., Tjukavkin, A., Bolgov, D., Kamanin, D., Kopach, Yu., Kuznetsova, E., Tishchenko, V., Khlebnikov, S., and Tyurin, G.. Tue . "Searching for Rare Decay Modes in the Reaction 238U+4He (40 MeV)". United States. doi:10.1063/1.2746590.
@article{osti_21061795,
title = {Searching for Rare Decay Modes in the Reaction 238U+4He (40 MeV)},
author = {Pyatkov, Yu. and Lavrova, J. and Trzaska, W. and Yamaletdinov, S. and Lyapin, V. and Sillanpaeae, M. and Mutterer, M. and Tjukavkin, A. and Bolgov, D. and Kamanin, D. and Kopach, Yu. and Kuznetsova, E. and Tishchenko, V. and Khlebnikov, S. and Tyurin, G.},
abstractNote = {In the present paper we describe an experiment performed on the reaction 238U + 4He (40 MeV) using a two-arm TOF-E (time-of-flight vs. energy) spectrometer with micro- channel plate detectors and mosaics of PIN diodes. This experiment has aimed at searching for fine structures in the total kinetic energy vs. fragment mass (TKE - M) distributions of binary events, and disclosing rare ternary decay modes others than already known from ternary fission. Details of the procedures of data handling are briefly described as well.},
doi = {10.1063/1.2746590},
journal = {AIP Conference Proceedings},
number = 1,
volume = 912,
place = {United States},
year = {Tue May 22 00:00:00 EDT 2007},
month = {Tue May 22 00:00:00 EDT 2007}
}
  • The 10B(n,{alpha})7Li reaction was studied in the energy range between 1.5 MeV and 5.6 MeV at the 7-MV Van de Graaff accelerator of IRMM by using a gridded ionisation chamber, signal digitisation, and an intrinsic 238U neutron monitor. The aim was to obtain accurate data for the IAEA Coordinated Research Project (CRP) on the improvement of standard cross sections for light elements. The effect of particle leaking was discovered and its implications investigated. The determination of the cross section {sigma}({alpha}0+{alpha}1) strongly benefits from it but measurements of angular distributions, individual cross sections {sigma}({alpha}0) and {sigma}({alpha}1), and the branching ratio {alpha}0/{alpha}1more » are negatively affected. The correct number of reaction events was obtained by identification of unknown particle signatures in the energy spectra as 10B(n,{alpha})7Li events in the form of quasi 7Li+{alpha} particles created by particle leaking. The cross-section ratio 10B(n,{alpha})7Li/238U(n,fission) was measured and the excitation function of 10B(n,{alpha})7Li determined by simultaneously detecting the charged particles from the boron disintegration in the forward hemisphere and the 238U fission fragments in the backward hemisphere. The IRMM cross sections are compared to experimental data of other groups and to predictions of the ENDF/B-VI.8, JENDL-3.3, and JEF-2.2 evaluations.« less
  • Isotopes of rutherfordium (258-261Rf) were produced in irradiations of 238U targets with 26Mg beams. Excitation functions were measured for the 4n, 5n and 6n exit channels. Production of 261Rf in the 3n exit channel with a cross section of 28+92-26 pb was observed. Alpha decay of 258Rf was observed for the first time with an alpha-particle energy of 9.05+-0.03 MeV and an alpha/total decay branching ratio of 0.31+-0.11. In 259Rf, the electron capture/total decay branching ratio was measured to be 0.15+-0.04. The measured half-lives for 258Rf, 259Rf and 260Rf were 14.7+1.2-1.0 ms, 2.5+0.4-0.3 s and 22.2+3.0-2.4 ms, respectively, in agreementmore » with literature data. The systematics of the alpha decay Q values and of the partial spontaneous fission half-lives were evaluated for even-even nuclides in the region of the N = 152, Z = 100 deformed shell. The influence of the N = 152 shell on the alpha decay Q values for rutherfordium was observed to be similar to that of the lighter elements (96<_ Z<_ 102). However, the N = 152 shell does not stabilize the rutherfordium isotopes against spontaneous fission, as it does in the lighter elements (96<_ Z<_102).« less
  • This article presents a new analysis of primary projectile-like fragments produced in peripheral and mid-peripheral collisions in the reaction [sup 40]Ca+[sup nat]Cu at 35 MeV/nucleon. The data were obtained using the charged particle AMPHORA array. The distributions of multiplicity, inclusive charge, and heaviest fragment charge of the deexcitation products as well as the moments characterizing the single event charge partitions are remarkably well reproduced by a statistical sequential binary decay model even up to excitation energies of more than 8 MeV/nucleon. The results produced by the sequential binary decay model and a simple bond percolation model are qualitatively very similar.more » However the sequential binary decay mechanism leads to charge fluctuations which are in better agreement with the data than those predicted by the percolation model.« less
  • It has been controversial whether {eta}{sub b} can be discovered in Tevatron Run 2 through the decay {eta}{sub b}{yields}J/{psi}J/{psi} followed by J/{psi}{yields}{mu}{sup +}{mu}{sup -}. I clear this controversy by an explicit calculation which predicts Br[{eta}{sub b}{yields}J/{psi}J/{psi}] to be of order 10{sup -8}. It is concluded that observing {eta}{sub b} through this decay mode in Tevatron Run 2 may be rather unrealistic. The {eta}{sub b} may be observed in the forthcoming CERN LHC experiments through the 4-lepton channel, if the background events can be significantly reduced by imposing some kinematical cuts. By some rough but plausible considerations, I find that themore » analogous decay processes {eta}{sub b}{yields}VV, D*D* also have very suppressed branching ratios; nevertheless it may be worth looking for {eta}{sub b} at LHC and Super B factory through the decay modes {eta}{sub b}{yields}K{sub S}K{sup {+-}}{pi}{sup {+-}}, D*D.« less