Use of single planar Ge(Li) detectors as gamma-ray polarimeters

1970 ◽  
Vol 48 (19) ◽  
pp. 2320-2330 ◽  
Author(s):  
A. E. Litherland ◽  
G. T. Ewan ◽  
S. T. Lam
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Ion Beam ◽  
Quantitative Agreement ◽  
Polarization Sensitivity ◽  
Total Absorption ◽  
Asymmetry Ratio ◽  
Large Volume Detector ◽  
Lead Collimator

The polarization sensitivity of a single rectangular Ge(Li) detector 40 × 25 × 3.5 mm has been studied as a function of energy using gamma rays of known linear polarization produced in (p,p′γ) reactions. The counting rates in the total absorption peaks were measured with the 40 × 25 mm face perpendicular [Formula: see text] and parallel [Formula: see text] to the plane defined by the ion beam and gamma-ray direction. The asymmetry ratio [Formula: see text] was measured using E2 gamma rays with known polarization. From these results the following values of Q for complete polarization were deduced for a series of energies: 0.847 MeV (16.4 ± 1.0)%, 1.368 MeV (13.1 ± 1.0)%, 1.779 MeV (12.4 ± 1.5)%, and 4.43 MeV (6.4 ± 1.0)%. These results were in quantitative agreement with calculations made using the Klein–Nishina formula. A large volume detector 60 × 35 × 6.5 mm was studied in a similar manner. The corresponding results for complete polarization are: 0.847 MeV (16.4 ± 1.0)%, 1.368 MeV (14.3 ± 2.0)%, 1.779 MeV (11.6 ± 1.2)%, and 4.43 MeV (5.8 ± 1.5)%. These values are slightly higher than those obtained in calculations. Tests were also made with a lead collimator 6.25 cm long with an aperture of 1 cm in front of the larger polarimeter. The results for complete polarization are: 1.779 MeV (14.0 ± 1.5)% and 4.43 MeV (9.0 ± 1.0)%. Some recent applications of high-resolution Ge(Li) linear polarimeters are briefly discussed.

THE DECAY OF Pm149

1960 ◽  
Vol 38 (12) ◽  
pp. 1577-1585 ◽  
Author(s):  
Agda Artna ◽  
Margaret E. Law
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Conversion Coefficient ◽  
Beta Spectrum ◽  
Multichannel Analyzer ◽  
Coincidence Spectrometer ◽  
Beta Spectrometer ◽  
Beta Group

The 52.8-hour activity of Pm149 has been investigated using a high resolution beta spectrometer, a lens type coincidence spectrometer, and a scintillation spectrometer in conjunction with a multichannel analyzer. The beta spectrum was found to consist of two groups with maximum energies of 1.072 ± 0.002 Mev and 0.786 ± 0.004 Mev, and intensities of 97.1 ± 0.4% and 2.9 ± 0.4% respectively. A gamma ray of energy 285.7 ± 0.3 kev was found to be in coincidence with the 0.786-Mev beta group. No other gamma rays with intensities greater than 0.1% were found. The K conversion coefficient for the 286-kev transition was measured to be 0.075 ± 0.008. This together with the values of 6.5 ± 0.7 and 4 ± 1 obtained for the K/L and L/M conversion ratios respectively indicate that this transition is M1 in character with less than 10% E2 admixture.

Gamma-ray production in the 170Er(p,n)170Tm nuclear reaction

Open Physics ◽  
2010 ◽  
Vol 8 (4) ◽  
Author(s):  
Alexandru Mihailescu ◽  
Gheorghe Cata-Danil
Keyword(s):  
High Resolution ◽  
Energy Range ◽  
Nuclear Reaction ◽  
Gamma Rays ◽  
Compound Nucleus ◽  
Beam Energy ◽  
Gamma Ray ◽  
Excitation Functions ◽  
Γ Ray ◽  
First Time

AbstractFor the first time discrete gamma-rays following the nuclear reaction 170Er(p,n)170Tm with enriched target were measured with a high resolution GeHP spectrometer. Protons delivered by the Bucharest FN Tandem Van de Graaff accelerator bombarded a thin self-supporting film of enriched erbium. Measured γ-ray energies (Eγ), their relative intensities (Iγ) and corresponding excitation functions for the beam energy range 2.0–3.6 MeV are reported in the present work. The measured excitation functions were fairly well reproduced by compound nucleus calculations based on the Hauser-Feshbach formalism.

Oxygen Ion Induced Charge in SiC MOS Capacitors Irradiated with Gamma-Rays

2011 ◽  
Vol 679-680 ◽  
pp. 362-365 ◽  
Author(s):  
Takeshi Ohshima ◽  
Naoya Iwamoto ◽  
Shinobu Onoda ◽  
Takahiro Makino ◽  
Shinji Nozaki ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Ion Beam ◽  
Gate Oxide ◽  
Peak Amplitude ◽  
Induced Current ◽  
Mos Capacitors ◽  
Oxygen Ion ◽  
Before And After ◽  
Gamma Ray Irradiation

Charge induced in 6H-SiC nMOS capacitors by 15 MeV oxygen ion microbeams was measured using Transient Ion Beam Induced Current (TIBIC) before and after gamma-ray irradiations. The peak amplitude of TIBIC signals decreases and the fall time increases with increasing number of incident ions. The decrease in the TIBIC peak eventually saturated. The TIBIC signal can be refreshed to its original shape by applying a positive bias of + 1V to gate oxide. Small decrease in both the peak amplitude of TIBIC signal and collected charge was observed due to gamma-ray irradiation.

High-resolution gamma-ray study of 185Wm

1970 ◽  
Vol 48 (5) ◽  
pp. 502-510 ◽  
Author(s):  
S. C. Gujrathi ◽  
J. M. D'auria
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Ground State ◽  
Internal Conversion ◽  
Gamma Ray ◽  
X Ray ◽  
Isomeric Level ◽  
Coincidence System ◽  
Internal Conversion Coefficients ◽  
Conversion Coefficients

The decay of 185Wm has been investigated using a high-resolution Ge(Li) X-ray spectrometer and a Ge(Li)–NaI(Tl) coincidence system. The energies and relative intensities (given in parentheses) of the observed gamma rays associated with the decay of the 185Wm (T1,2 = 1.68 min) are: 23.54 (3.3), 42.29 (1.1), 65.857 (100), 93.30 (0.5), 94.59 (2.2), 107.850 (6.8), 122.05 (1.5), 131.554 (84.0), 164.334 (11), 173.675(61.5),and 187.879(15.4) keV. The energy of the isomeric level has been deduced to be 197.41 keV and decays to the ground state through levels at 187.88, 173.68, 93.29, 65.86, and 23.54 keV. In addition, it was deduced experimentally from measured internal-conversion coefficients that the multipolarity of the 131.55 keV transition is E3 while the 65.86 keV transition is an M1 + E2 mixture with a 30 ± 7.5% M1 component.

Low Energy Gamma Transitions in 171Tm

1970 ◽  
Vol 25 (7) ◽  
pp. 1043-1045 ◽  
Author(s):  
M. S. El-Nesr
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Low Energy ◽  
Conversion Coefficients ◽  
Energy Gamma ◽  
Gamma Transitions ◽  
Double Focusing

The low energy gamma-ray spectrum of 171Er has been studied with the use of both Ge (Li) gamma-ray and a high resolution iron free double focusing beta-ray spectrometer. The data provide K-conversion coefficients and multipolarities of eight gamma-rays. Spin and parity assignments 7/2+, 3/2+, 5/2+ and 5/2+ are given to the 636, 676, 738 and 913 keV levels respectively

Decay of 101Mo and 101Tc

1972 ◽  
Vol 50 (17) ◽  
pp. 1957-1977 ◽  
Author(s):  
W. B. Cook ◽  
M. W. Johns
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Energy Levels ◽  
Spin Parity ◽  
Coincidence Data ◽  
Parameter Configuration ◽  
Coincidence Spectrometer ◽  
Gamma Transitions ◽  
Two Parameter

The energy levels of 101Tc and 101Ru have been investigated through a study of the decays of 14.6 min 101Mo and 14.0 min 101Tc. Singles gamma-ray spectra were obtained with high-resolution Ge(Li) detectors having volumes of 0.8 cm3 and 12 cm3. A 36 cm3 Ge(Li)–40 cm3 Ge(Li) coincidence spectrometer operated in a two-parameter configuration (4096 × 4096) was employed in collecting coincidence data. More than 180 gamma transitions have been observed in the two decays: 152 are definitely assigned to the decay of 101Mo, 25 to the decay of 101Tc. These gamma rays have been incorporated into level schemes involving 45 levels in 101Tc and 10 levels in 101Ru. On the basis of beta and gamma selection rules, spin–parity assignments have been suggested for many of the levels.

On the possible gamma-ray source in Cygnus

1967 ◽  
Vol 31 ◽  
pp. 469-471
Author(s):  
J. G. Duthie ◽  
M. P. Savedoff ◽  
R. Cobb
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Right Ascension

A source of gamma rays has been found at right ascension 20h15m, declination +35°, with an uncertainty of 6° in each coordinate. Its flux is (1·5 ± 0·8) x 10-4photons cm-2sec-1at 100 MeV. Possible identifications are reviewed, but no conclusion is reached. The mechanism producing the radiation is also uncertain.

Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

1994 ◽  
Vol 144 ◽  
pp. 635-639
Author(s):  
J. Baláž ◽  
A. V. Dmitriev ◽  
M. A. Kovalevskaya ◽  
K. Kudela ◽  
S. N. Kuznetsov ◽  
...  
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
Gamma Rays ◽  
Pulse Shape ◽  
Gamma Ray ◽  
Pulse Shape Discrimination ◽  
Shape Discrimination ◽  
Solar Neutron ◽  
Low Altitude

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.

FIB Enhancement of Mechanically Polished Cross-sections

2019 ◽  
Author(s):  
Becky Holdford
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Resolution Imaging ◽  
Chemical Attack ◽  
Resolution Imaging ◽  
Scanning Electron

Abstract On mechanically polished cross-sections, getting a surface adequate for high-resolution imaging is sometimes beyond the analyst’s ability, due to material smearing, chipping, polishing media chemical attack, etc.. A method has been developed to enable the focused ion beam (FIB) to re-face the section block and achieve a surface that can be imaged at high resolution in the scanning electron microscope (SEM).

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