scholarly journals Resonance Neutron Capture in 86,87Sr

1982 ◽  
Vol 35 (3) ◽  
pp. 267 ◽  
Author(s):  
GC Hicks ◽  
BJ Allen ◽  
AR de L Musgrove ◽  
RL Macklin
Keyword(s):  
Cross Sections ◽  
Neutron Capture ◽  
High Energy ◽  
P Wave ◽  
High Energy Resolution ◽  
Electron Linear Accelerator ◽  
Resonance Neutron ◽  
Oak Ridge ◽  
Average Resonance ◽  
Capture Cross Sections

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

scholarly journals Resonance Neutron Capture in 138Ba and 140Ce and the Prompt Neutron Correction to ?-ray Detectors

1979 ◽  
Vol 32 (3) ◽  
pp. 213 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Alien ◽  
RL Macklin
Keyword(s):  
Cross Sections ◽  
Neutron Capture ◽  
High Energy ◽  
P Wave ◽  
Prompt Neutron ◽  
High Energy Resolution ◽  
Capture Cross ◽  
S Wave ◽  
Strength Functions ◽  
Capture Cross Sections

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.

scholarly journals Resonant Neutron Capture in 139La

1977 ◽  
Vol 30 (6) ◽  
pp. 599 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Allen ◽  
RL Macklin
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Strength Function ◽  
High Energy ◽  
P Wave ◽  
High Energy Resolution ◽  
Capture Cross ◽  
Electron Linear Accelerator ◽  
Oak Ridge

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.

Resonance neutron capture and transmission measurements and the stellar neutron capture cross sections ofBa134andBa136

1996 ◽  
Vol 54 (3) ◽  
pp. 1463-1477 ◽  
Author(s):  
P. E. Koehler ◽  
R. R. Spencer ◽  
R. R. Winters ◽  
K. H. Guber ◽  
J. A. Harvey ◽  
...  
Keyword(s):  
Cross Sections ◽  
Neutron Capture ◽  
Capture Cross ◽  
Resonance Neutron ◽  
Transmission Measurements ◽  
Capture Cross Sections

scholarly journals Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications

2012 ◽  
Vol 85 (4) ◽  
Author(s):  
C. Massimi ◽  
P. Koehler ◽  
S. Bisterzo ◽  
N. Colonna ◽  
R. Gallino ◽  
...  
Keyword(s):  
Cross Sections ◽  
Neutron Capture ◽  
Capture Cross ◽  
Magnesium Isotopes ◽  
Resonance Neutron ◽  
Capture Cross Sections

THERMAL NEUTRON CAPTURE CROSS-SECTION OF Na23 AND Mn55

1953 ◽  
Vol 31 (3) ◽  
pp. 204-206 ◽  
Author(s):  
Rosalie M. Bartholomew ◽  
R. C. Hawkings ◽  
W. F. Merritt ◽  
L. Yaffe
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Cross Sections ◽  
Neutron Capture ◽  
Half Life ◽  
Capture Cross Section ◽  
Thermal Neutron Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Capture Cross Sections

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.

scholarly journals In-situ observation of trapped carriers in organic metal halide perovskite films with ultra-fast temporal and ultra-high energetic resolutions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kanishka Kobbekaduwa ◽  
Shreetu Shrestha ◽  
Pan Adhikari ◽  
Exian Liu ◽  
Lawrence Coleman ◽  
...  
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
High Energy Resolution ◽  
In Situ Observation ◽  
Trap States ◽  
Tunneling Mechanism ◽  
Photocurrent Spectroscopy ◽  
Metal Halide Perovskite ◽  
Halide Perovskite

AbstractWe in-situ observe the ultrafast dynamics of trapped carriers in organic methyl ammonium lead halide perovskite thin films by ultrafast photocurrent spectroscopy with a sub-25 picosecond time resolution. Upon ultrafast laser excitation, trapped carriers follow a phonon assisted tunneling mechanism and a hopping transport mechanism along ultra-shallow to shallow trap states ranging from 1.72–11.51 millielectronvolts and is demonstrated by time-dependent and independent activation energies. Using temperature as an energetic ruler, we map trap states with ultra-high energy resolution down to < 0.01 millielectronvolt. In addition to carrier mobility of ~4 cm2V−1s−1 and lifetime of ~1 nanosecond, we validate the above transport mechanisms by highlighting trap state dynamics, including trapping rates, de-trapping rates and trap properties, such as trap density, trap levels, and capture-cross sections. In this work we establish a foundation for trap dynamics in high defect-tolerant perovskites with ultra-fast temporal and ultra-high energetic resolution.

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