scholarly journals Accurate Branching Ratio Measurements in 31P(P,g)32S

1975 ◽  
Vol 28 (4) ◽  
pp. 383 ◽  
Author(s):  
SG Boydell ◽  
DG Sargood

The reaction 3 1p(p, y)32S has been investigated in the proton energy range 0'4-1'75 MeV. Gamma ray spectra were measured for 2S resonances with Ge(Li) detectors which were carefully calibrated for relative peak efficiencies. Allowance was made for the effect of anisotropies in all the emitted y-rays. The spectra have been analysed to give branching ratios for bound and unbound levels. Comparisons made with previous work reveal some differences.

1975 ◽  
Vol 28 (4) ◽  
pp. 369 ◽  
Author(s):  
SG Boydell ◽  
DG Sargood

The reaction 23Na(p, y)24Mg has been investigated in the proton energy range O' 3-1' 75 MeV. Gamma ray spectra were measured for 22 resonances with Ge(Li) detectors which were carefully calibrated for relative peak efficiencies. Allowance was made for the effect of anisotropies in all the emitted y-rays. The speCtra have been analysed to give branching ratios for bound and unbound levels.


1957 ◽  
Vol 35 (9) ◽  
pp. 1042-1056 ◽  
Author(s):  
D. A. Bromley ◽  
H. E. Gove ◽  
A. E. Litherland ◽  
E. Almqvist ◽  
E. B. Paul

Information on the low levels in Si29 has been obtained by studying the gamma radiation associated with the Si29(p, p′γ)Si29 inelastic-scattering reaction in the proton-energy range from 2.5 to 3.0 Mev. and with the Al29(β−)Si29 negatron decay. Angular-distribution measurements have shown that the 2.03 Mev. level in Si29 has spin 5/2, and are consistent with a 3/2 assignment to the 1.28 Mev. level. The E2/M1E2 branching ratio for the de-excitation of the 2.03 Mev. state has been measured to be approximately 100. Log ft values of < 5.2, > 6.5, and 5.2 have been determined for the branches of the Al29 decay to the 2.43, 2.03, and 1.28 Mev. states in Si29.


2021 ◽  
Vol 647 ◽  
pp. A127
Author(s):  
Lichang Guan ◽  
Pan Jiang ◽  
Guodong Zhang ◽  
Tonghui Yin ◽  
Min Cheng ◽  
...  

Carbon monoxide (CO) is one of the most abundant molecular species in comets. Its photodissociation by the solar radiation in the vacuum ultraviolet (VUV) region produces excited atomic fragments C(1D), C(1S), and O(1D), which radiate at characteristic wavelengths when they decay to lower states. The fractional rate constants for generating these fragments from CO photodissociation under the entire range of the solar radiation field are key input values in modelling the observed atomic emission intensities from comets. In this study, the branching ratios of the four lowest dissociation channels C(3P)+O(3P), C(1D)+O(3P), C(3P)+O(1D), and C(1S)+O(3P) of the 12C16O photodissociation are measured in the VUV energy range between the threshold of producing the C(1S)+O(3P) channel (~110 500 cm−1) and the ionisation energy (IE) of 12C16O (~113 045 cm−1). We measured these ratios using the VUV time-slice velocity-map ion imaging apparatus. We observe a number of high Rydberg states in the aforementioned energy range, with most of them mainly producing ground C(3P) and O(3P) atomic fragments, and only a few of them producing a significant amount of excited C(1D) or O(1D) fragments. We also observe the excited C(1S) fragment from CO photodissociation and measured its branching ratio for the first time. Based on the photodissociation branching ratios measured in the current and previous studies, we are able to estimate the relative percentages of the excited atomic fragments C(1D), C(1S), and O(1D) from the solar photolysis of 12C16O below its IE. We discuss the implications for the photochemical modelling of the CO-dominated comet C/2016 R2 (Pan-STARRS).


1994 ◽  
Vol 144 ◽  
pp. 635-639
Author(s):  
J. Baláž ◽  
A. V. Dmitriev ◽  
M. A. Kovalevskaya ◽  
K. Kudela ◽  
S. N. Kuznetsov ◽  
...  

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.


1974 ◽  
Vol 52 (23) ◽  
pp. 2329-2342 ◽  
Author(s):  
R. W. Ollerhead ◽  
D. C. Kean ◽  
R. M. Gorman ◽  
M. B. Thomson

All levels below 5.2 MeV in 25Mg have been studied using the reaction 25Mg(p, p′γ). In-elastically scattered protons were detected in an annular surface barrier detector located at 180°; coincidence gamma-ray spectra were obtained at Ge (Li) detector angles of 90°, 45°, and 135°. Level energies were determined from unshifted gamma-ray energies recorded in the 90° spectra. Lifetimes were obtained from the attenuated Doppler shift of gamma-ray energies recorded in spectra taken at forward and backward angles. Branching ratios were deduced from the combined data of all three angles. The identification of levels as members of rotational bands is discussed, and transition strengths deduced from the present measurements are compared with predictions of the simple rotational model.


2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Aoife Bharucha ◽  
Diogo Boito ◽  
Cédric Méaux

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.


1970 ◽  
Vol 48 (7) ◽  
pp. 827-833 ◽  
Author(s):  
S. T. Lam ◽  
A. E. Litherland ◽  
J. J. Simpson

The 1459-keV level of 19F was populated by the 19F(p,p′γ)19F reaction at a proton energy of 2.78 MeV. The E2/M1 mixing ratio for the 1459 → 110 keV transition was determined to be [Formula: see text] from a combination of the γ-ray angular distribution and linear polarization and the nuclear lifetime. The γ-ray angular distribution was measured with a coaxial Ge(Li) detector and the γ-ray linear polarization with a planar Ge(Li) detector. The corresponding E2 and M1 transition strengths for a lifetime of 0.084 ± 0.020 ps are found to be [Formula: see text] and 0.10 ± 0.03 W.u. respectively. They are in good agreement with the particle–hole calculations of Benson and Flowers. The branching ratios of the 1459-keV level agree well with those of Poletti et al. The γ-ray transitions from the 1459-keV level provide a good example for demonstrating the usefulness of a single crystal Ge(Li) polarimeter.


2002 ◽  
Vol 17 (12n13) ◽  
pp. 1799-1808 ◽  
Author(s):  
MARCO TAVANI

Gamma-ray astrophysics in the energy range between 30 MeV and 30 GeV is in desperate need of arcminute angular resolution and source monitoring capability. The AGILE Mission planned to be operational in 2004-2006 will be the only space mission entirely dedicated to gamma-ray astrophysics above 30 MeV. The main characteristics of AGILE are the simultaneous X-ray and gamma-ray imaging capability (reaching arcminute resolution) and excellent gamma-ray timing (10-100 microseconds). AGILE scientific program will emphasize a quick response to gamma-ray transients and multiwavelength studies of gamma-ray sources.


1997 ◽  
Vol 487 ◽  
Author(s):  
E. Caroli ◽  
G. Bertuccio ◽  
G. De Cesare ◽  
A. Donati ◽  
W. Dusi ◽  
...  

AbstractAn important region of the electromagnetic spectrum for astrophysics is the hard X- and gamma ray band between 10 keV and a few MeV, where several processes occur in a wide variety of objects and with different spatial distribution and time scales. In order to fulfill the observational requirements in this energy range and taking into account the opportunities given by small/medium size missions (e.g. on the ISS), we have proposed a compact, wide field camera based on a thick (1 cm) position sensitive CdTe detector (PSD). The detector is made of an array of 128×96 CdTe microspectrometers with a pixel size of 2×2 mm2. The basic element of the PSD is the linear module that is an independent detection unit with 32 CdTe crystals and monolithic front-electronics (ASIC) supported by a thin (300 μm) ceramic layer. The expected performance of the PSD over the operative energy range and some of the required ASIC functionality are presented and discussed.


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