Gamma rays from the 3702 keV level in 25Al

1969 ◽  
Vol 47 (23) ◽  
pp. 2609-2619 ◽  
Author(s):  
N. Anyas-Weiss ◽  
A. E. Litherland
Keyword(s):  
Angular Distribution ◽  
Lower Limit ◽  
Gamma Rays ◽  
Doppler Shift ◽  
Gamma Ray ◽  
Decay Modes ◽  
Mirror Nucleus ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
Decay Gamma

The decay modes of the 7/2−, 3702 keV level in 25Al have been studied at the Ep = 1490 keV resonance in the 24Mg(p,γ)25Al reaction. The decay gamma rays were observed using a 25 cm3 Ge(Li) detector. A previously unreported 2% transition from the resonance to the level at 2723 keV has been observed. The angular distribution of this gamma ray admits only a spin of 7/2 for the 2723 keV level. The lifetime of the 2723 keV level was measured with the Doppler shift attenuation method (DSAM) at the 1660 keV resonance and was found to be [Formula: see text]. The lifetime of the 5/2+, 1790 keV level has been measured using the DSAM and has been found to be [Formula: see text]. From Doppler shift measurements a lower limit for the lifetime of the 3/2+, 945 keV level of [Formula: see text] was obtained. From angular distribution measurements at the Ep = 1490 keV resonance, the following multipole mixing ratios have been measured: δ(R → 0) = 0.00 ± 0.02; δ(R → 1790) = −0.02 ± 0.02; δ(R → 2723) = 0.15 ± 0.30; [Formula: see text]; δ(1790 → 945) = −0.15 ± 0.05; δ(945 → 0) = 0.35 ± 0.10 or 1.7 ± 0.2; δ(945 → 451) = −0.15 ± 0.05 or 2.6 ± 0.4. Comparisons with data in the mirror nucleus 25Mg have been made.

scholarly journals Gamma-ray Studies using a Solid Argon Target: Properties of States in 40K and 40Ar

1979 ◽  
Vol 32 (3) ◽  
pp. 195 ◽  
Author(s):  
DJ Beale ◽  
AR Poletti ◽  
JR Southon
Keyword(s):  
Angular Distribution ◽  
Doppler Shift ◽  
Weak Coupling ◽  
Gamma Ray ◽  
Interaction Model ◽  
Substantial Agreement ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
Coupling Calculation ◽  
Solid Argon

The Doppler shift attenuation method was used to deduce lifetimes of levels in 40 Ar and 4�K populated by the reactions 40 Ar(p, n)4�K and 40 Ar(p, p')40 Ar. Spins and mixing ratios in 4�K were also deduced from angular distribution measurements. The target used was solid argon at a temperature of 66 K. Substantial agreement with other recent work has been found. The results are interpreted using a weak coupling calculation and a simple t5 function interaction model.

Lifetimes and decay modes of energy levels in 25Mg

1968 ◽  
Vol 46 (18) ◽  
pp. 2039-2053 ◽  
Author(s):  
J. F. Sharpey-Schafer ◽  
R. W. Ollerhead ◽  
A. J. Ferguson ◽  
A. E. Litherland
Keyword(s):  
Gamma Rays ◽  
Doppler Shift ◽  
Energy Levels ◽  
Branching Ratios ◽  
Collective Model ◽  
Incident Proton ◽  
Crystal Spectrometer ◽  
Decay Modes ◽  
Mirror Nucleus ◽  
Doppler Shift Attenuation

Lifetimes of energy levels in 25Mg have been measured using the Doppler-shift attenuation method. The levels were exicted by the 25Mg(p, p′γ) reaction with incident proton energies between 3.8 and 7.0 MeV. The gamma rays were detected in a three-crystal spectrometer consisting of a 40 cm3 Ge(Li) detector surrounded by a large NaI(Tl) crystal in the form of a split annulus. Mean lifetimes found, given in fs, are: τ(1611-keV level) = [Formula: see text], τ(1962) = [Formula: see text], τ(2565) = 59 ± 26, τ(2736) = 288 ± 20, τ(2803) = 27 ± 6, τ(3399) = 33 ± 19, τ(3408) < 20, τ(3903) < 20, τ(3969) = 24 ± 11, τ(4055) = 53 ± 10, and τ(5005) < 26. The decay modes and branching ratios of levels up to 4055-keV excitation are given. The results are compared with the mirror nucleus 25Al and discussed in terms of the collective model.

Lifetime measurements of the six lowest lying levels in 35Cl

1969 ◽  
Vol 47 (12) ◽  
pp. 1295-1306 ◽  
Author(s):  
F. Ingebretsen ◽  
T. K. Alexander ◽  
O. Häusser ◽  
D. Pelte
Keyword(s):  
Gamma Rays ◽  
Doppler Shift ◽  
Gamma Ray ◽  
Level Structure ◽  
Branching Ratios ◽  
Distance Method ◽  
Lifetime Measurements ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
Recoil Distance

The energies, gamma-ray branching ratios, and mean nuclear lifetimes of the six lowest lying levels in 35Cl have been measured. Gamma rays following the reaction 32S(α,pγ)35Cl were studied using two Ge(Li) detectors with 15-cm3 and 40-cm3 active volumes respectively. The lifetimes of the five lowest lying levels were measured using the Doppler shift attenuation method, with the results: 1219 keV, [Formula: see text]; 1763 keV, 0.55 ± 0.15 ps; 2646 keV, 0.30 ± 0.09 ps; 2695 keV, <0.03 ps; and 3003 keV, <0.05 ps. The lifetime of the 3163-keV level was measured to be 60 ± 7 ps, using a recoil distance method. The level structure is discussed taking into account known lifetimes, spins, parities, and gamma-ray mixing ratios.

Gamma-Ray Angular Distribution, Angular Correlation, Linear Polarization, and Doppler-Shift Attenuation Measurements in the 46Ti(α, nγ) 49Cr Reaction

1977 ◽  
Vol 43 (3) ◽  
pp. 741-754 ◽  
Author(s):  
Jirohta Kasagi ◽  
Shigeru Nakagawa ◽  
Norio Kishida ◽  
Yuichi Iritani ◽  
Hajime Ohnuma
Keyword(s):  
Angular Distribution ◽  
Angular Correlation ◽  
Linear Polarization ◽  
Doppler Shift ◽  
Gamma Ray ◽  
Doppler Shift Attenuation

Properties of the 9.699 MeV level in 28Si

1969 ◽  
Vol 47 (16) ◽  
pp. 1725-1729 ◽  
Author(s):  
N. Anyas-Weiss ◽  
A. M. Charlesworth ◽  
L. E. Carlson ◽  
K. P. Jackson ◽  
R. E. Azuma
Keyword(s):  
Lower Limit ◽  
Gamma Rays ◽  
Large Volume ◽  
Doppler Shift ◽  
Branching Ratios ◽  
Doppler Shift Attenuation ◽  
Doppler Shift Attenuation Method

The decay of the 9.699 MeV level in 28Si has been studied using the reaction 27Al(p,γ)28Si at Ep = 1724 keV. Gamma rays from the decay of the 9.699 MeV level were observed with large-volume Ge(Li) detectors. Branching ratios for the decay of the 9.699 MeV level have been obtained and a lower limit for the lifetime of this level has been measured to be [Formula: see text] using the Doppler-shift attenuation method.

Lifetimes in 32S

1970 ◽  
Vol 48 (1) ◽  
pp. 47-55 ◽  
Author(s):  
R. W. Ollerhead ◽  
T. K. Alexander ◽  
O. Häusser
Keyword(s):  
Gamma Rays ◽  
Ground State ◽  
Doppler Shift ◽  
State Transition ◽  
Gamma Ray ◽  
Branching Ratio ◽  
Dipole Transition ◽  
Average Lifetime ◽  
Line Shapes ◽  
Doppler Shift Attenuation

Lifetimes have been measured for five levels in 32S. The levels were populated by inelastic scattering of protons, and the gamma rays were detected at angles between 0° and 127° using a 40 cm3 Ge(Li) detector mounted inside a split annular NaI(Tl) crystal. The spectrometer was used simultaneously as both an escape-suppressed and a three-crystal pair spectrometer. Decay schemes and lifetimes have been determined using thick targets of PbS, MoS2, and sulfur cooled to 77 °K. Lifetime information was obtained both from analysis of the observed gamma-ray line shapes and from analysis of the Doppler shift attenuation in the different target materials. The two methods of analysis agree within the errors. A weak ground-state transition was observed from the J = 3 level at 5.012 MeV, establishing its parity as negative. Analysis of the line shape observed at 0° and the Doppler shift attenuation gave an average lifetime of 7.5 ± 0.5 × 10−13 s. The observed branching ratio (4 ± 0.4% to the ground state) implies an E3 enhancement of 20 ± 2.4 Weisskopf units (W.u.). A similar analysis gave a lifetime of 4.9 ± 0.9 × 10−13 s for the J = 1 level at 4.699 MeV, which implies that the dipole transition to the ground state is highly retarded. Lifetimes have also been measured for levels at 3.780 MeV [Formula: see text], 4.288 MeV (7.4 ± 0.6 × 10−14 s), and 5410 MeV (1.9 ± 0.2 × 10−13 s); the transition strengths are tabulated and discussed.

Transition rates in 29P

1970 ◽  
Vol 48 (22) ◽  
pp. 2683-2691 ◽  
Author(s):  
C. F. Monahan ◽  
H. C. Evans ◽  
J. H. Montague ◽  
W. R. Paulson ◽  
W. M. Zuk
Keyword(s):  
Excited States ◽  
Gamma Rays ◽  
Doppler Shift ◽  
Resonance Level ◽  
Transition Rates ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
The Mean ◽  
Doppler Shift Attenuation Method ◽  
Mean Lifetimes

Lifetimes of three of the low-lying excited states in 29P, populated in the 28Si(p,γ) reaction, have been determined using the Doppler shift attenuation method. The mean lifetimes of states at 4.085, 1.956, and 1.385 MeV were found to be 15 ± 4, 370 ± 80, and 200 ± 60 fs.Angular distribution measurements have also been performed on gamma rays resulting from the decay of the 4.085 MeV resonance level. The decay was found to go via states at 3.107 MeV (3%), 1.956 MeV (54%), and 1.385 MeV (43%). The spin of the resonance level was uniquely assigned as 7/2 and the multipole mixing ratios of the 2.129 and 1.385 MeV transitions as + 0.17 ± 0.05 and + 0.303 ± 0.050 respectively. The consequent transition rates indicate that the parity of the resonance level is positive.

Study of Low-Lying Levels in 37Ar

1972 ◽  
Vol 50 (11) ◽  
pp. 1182-1194 ◽  
Author(s):  
P. Taras ◽  
A. Turcotte ◽  
R. Vaillancourt
Keyword(s):  
Angular Distribution ◽  
Gamma Rays ◽  
Linear Polarization ◽  
Ground State ◽  
Solar Neutrino ◽  
Gamma Ray ◽  
Capture Rate ◽  
Mixing Ratio ◽  
Excitation Energies ◽  
Decay Gamma

The properties of the first five excited levels in 37Ar were investigated via the 37Cl(p,n)37Ar reaction at Ep = 3.98, 4.17, 4.38, and 4.81 MeV and via the 34S(α,n)37Ar reaction at Eα = 8.00, 8.50, and 8.60 MeV. The following excitation energies were obtained: Ex = 1409.7 ± 0.4, 1611.5 ± 0.4, 2217.8 ± 0.8, 2491.4 ± 0.8, and 2797.0 ± 0.8 keV. These levels were found to decay almost entirely to the ground state. The angular distribution and the linear polarization of the decay gamma rays of these levels were measured. From these measurements definite spin–parity assignments as well as values of the mixing ratio of the ground state gamma-ray transitions were obtained. These are: Ex(Jπ, δ) = 1612 ([Formula: see text], +0.11 ± 0.02), 2218 ([Formula: see text], 0.0 ± 0.02), 2491 ([Formula: see text]), and 2797 ([Formula: see text], −0.16 ± 0.03 or +8.0 ± 1.5, the value of −0.16 being more probable). The measurements were also consistent with a spin of [Formula: see text] for the 1410 keV level. The results are compared with a recent shell-model calculation and are discussed in the context of the solar neutrino capture rate in 37Cl.

Nuclear g Factors in 55Fe

1973 ◽  
Vol 51 (7) ◽  
pp. 707-712 ◽  
Author(s):  
P. G. Kerr ◽  
A. W. Gibb ◽  
J. A. Cameron
Keyword(s):  
Excited States ◽  
Gamma Rays ◽  
Target Material ◽  
Internal Field ◽  
Angular Distributions ◽  
Mixing Ratios ◽  
Decay Gamma ◽  
G Factors

The (α,n) reaction on natural chromium has been used to study levels in 55Fe up to 2.5 MeV excitation. Intensities and angular distributions of the decay gamma rays were measured, yielding branching and E2/M1 mixing ratios. In a magnetized target of the alloy Cr20Fe80, the rotation of the angular distributions was observed. Using recently determined lifetimes for the excited states and the average internal field of 277 kOe measured in the target material by Mössbauer absorption, the following g factors are obtained:[Formula: see text]

scholarly journals Partial and total thermal neutron capture cross sections for non-destructive assay and transmutation monitoring of 99Tc

2002 ◽  
Vol 90 (8) ◽  
Author(s):  
G. L. Molnár ◽  
T. Belgya ◽  
Zs. Révay ◽  
Syed M. Qaim
Keyword(s):  
Gamma Rays ◽  
Cross Sections ◽  
Neutron Capture ◽  
Gamma Ray ◽  
Cold Neutron ◽  
Production Cross ◽  
Radioactive Product ◽  
Non Destructive ◽  
Decay Gamma ◽  
Capture Cross Sections

SummaryAccurate partial gamma-ray production cross sections were determined for the prompt and radioactive product decay gamma rays following cold neutron capture in

Sign in / Sign up

Export Citation Format

Share Document