scholarly journals Resonant Neutron Capture in 139La

1977 ◽  
Vol 30 (6) ◽  
pp. 599 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Allen ◽  
RL Macklin

The neutron capture cross section of 139La has been measured with high energy resolution between 2� 5 and 90 ke V using the capture cross section facility at the 40 m station on the Oak Ridge Electron Linear Accelerator. Individual resonances were analysed to 15 keV and the average s- and p-wave radiative widths deduced were <Γγ>s = 55�6meV and <Γγ>p = 4O�7meV. The p-wave neutron strength function obtained was S1 = (0'30�0'1O)x 10-4 ? The s-wave resonances decay strongly to final f-wave states via a postulated doorway state mechanism. The transition strengths for these decays are not correlated with the neutron widths of the initial states.


1982 ◽  
Vol 35 (3) ◽  
pp. 267 ◽  
Author(s):  
GC Hicks ◽  
BJ Allen ◽  
AR de L Musgrove ◽  
RL Macklin

The neutron capture cross sections of 86.87Sr have been measured with high energy resolution from 3 to 200 keY at the 40 m station of the Oak Ridge Electron Linear Accelerator. Individual resonances were analysed to 37 keY for 86Sr and to 14 keY for 87Sr, and average resonance parameters were deduced on the basis of assumed divisions between s- and p-wave resonances. The average radiative widths obtained on this basis are consistent with a capture mechanism which is predominantly statistical



2018 ◽  
Vol 178 ◽  
pp. 04001
Author(s):  
Stephane Goriely ◽  
Stephane Hilaire ◽  
Sophie Péru

Valuable theoretical predictions of nuclear dipole excitations in the whole chart are of great interest for different nuclear applications, including in particular nuclear astrophysics. Here we extend our large-scale calculations of the E1 and M1 absorption γ-ray strength function obtained in the framework of the axially-symmetric deformed quasiparticle random phase approximation (QRPA) based on the finite-range D1M Gogny force to the determination of the de-excitation strength function. To do so, shell-model calculations of the de-excitation dipole strength function as well as experimental data are considered to provide insight in the low-energy limit and to complement the QRPA estimate phenomenologically. We compare our final prediction of the E1 and M1 strengths with available experimental data at low energies and show that a relatively good agreement can be obtained. Its impact on the average radiative width as well as radiative neutron capture cross section is discussed.



1976 ◽  
Vol 29 (3) ◽  
pp. 157 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Allen ◽  
JW Boldeman ◽  
RL Macklin

The neutron capture cross section of 137Ba has been measured to high resolution (AE/E ~ o� 2 %) below En = 60 keY. Average values of resonance parameters, extracted for resonances in the range 2�7 < En < 12 keY, are as follows: s-wave level spacing <D) = 380� 70 eV; s-wave radiative width <Tv). = 80�15meV; s-wave neutron strength function 104 So = 0'57�0'2; and p-wave neutron strength function 104 S1 = 0�45�0�2. The s-wave radiative width and the s-wave neutron strength function appear to be lower for 137Ba than for the other barium isotopes.



1977 ◽  
Vol 30 (6) ◽  
pp. 605 ◽  
Author(s):  
MJ Kenny ◽  
BJ Allen ◽  
RL Macklin

The neutron capture cross section of 45SC has been measured with 0�2 % energy resolution in the range 2�S-100keV. Many new I> 0 resonances are observed and the average s- and p-wave radiative widths and standard deviations are <Γγ>s = 0�84�0�46eV and <Γγ>p = 0�S�0�3eV. No significant correlation is observed between the reduced neutron widths and radiative widths of the s-wave resonances.



1979 ◽  
Vol 32 (3) ◽  
pp. 213 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Alien ◽  
RL Macklin

The neutron capture cross sections of 138Ba and 140Ce have been measured with high energy resolution between 3 and 100 keY using the capture cross section facility at the 40 m station of the Oak Ridge Electron Linear Accelerator. The average s-wave level spacings are <D)s = 6�3 � 1 �7 and 3�2 � 0�8 keY for 138Ba and 140Ce respectively. The deduced s-wave neutron strength functions are 104So = 1�0�0�4 and 1�54�0�53 respectively, and the average s-wave radiative widths are <r,)s = 55�20 and 35�9meY. The p-wave neutron strength functions are 104S1 ~ 0�03 and 0�32�0�12 respectively. The average 30 keY Maxwellian capture cross sections are 3�9�0�8mb for 138Ba and 7�7 � 0�9 mb for 140Ce. A more rigorous treatment of the prompt neutron correction for l'-ray detectors is described, and it is shown that previously published results for 138Ba have underestimated this correction. The 140Ce data provide excellent corroboration for the calculated magnitude and time dependence of the prompt neutron correction.



Author(s):  
Yu Kodama ◽  
Tatsuya Katabuchi ◽  
Gerard Rovira ◽  
Atsushi Kimura ◽  
Shoji Nakamura ◽  
...  


1953 ◽  
Vol 31 (3) ◽  
pp. 204-206 ◽  
Author(s):  
Rosalie M. Bartholomew ◽  
R. C. Hawkings ◽  
W. F. Merritt ◽  
L. Yaffe

The thermal neutron capture cross sections of Na23 and Mn55 have been determined using the activation method. The values are 0.53 ± 0.03 and 12.7 ± 0.3 barns respectively with respect to σAul97 = 93 barns. These agree well with recent pile oscillator results. The half-life for Mn56 is found to be 2.576 ± 0.002 hr.



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