Relative Intensities Of Gamma Rays Research Articles

Prompt gamma rays of terbium induced by inelastic scattering of fission neutrons

AbstractPrompt gamma rays of terbium emitted after (n,nʹγ) inelastic scattering reactions induced by irradiation of a terbium(III) hexahydrate (TbCl3·6H2O) sample with a beam of fission neutrons were investigated with the instrument FaNGaS (Fast Neutron-induced Gamma-ray Spectrometry) at an angle of 90° between neutron beam and detector. At sample position, the fast-neutron flux was 1.13 × 108 cm−2 s−1 and the neutron beam has an average energy of 2.30 MeV. We identified 124 prompt gamma lines from the 159Tb(n,nʹγ)159Tb reaction. Presence of prompt gamma rays from oxygen and chlorine was used for a concise verification of recently published results. Relative gamma-ray intensities, effective cross sections and fast-neutron spectrum-averaged partial production cross sections of the gamma lines are given including comparisons with available literature data. We found a reasonable agreement and the multitude of unreported lines adds decisive value to nuclear spectroscopy. Additionally, we estimated the detection limit of terbium as 1 mg for a counting time of 12 h.

A Technique of Efficiency Calibration of HPGe Detector

In this work, a technique for the determination of efficiency calibration of hyper-pure germa-nium detector was obtained using four different concentrations of KCl in Bq/l for different
 geometrical configurations. The relative intensities of Gamma-rays from 226Ra with its Gamma-Emitting daughters were used in addition to the normalizing factor relative to the intensities of
 gamma-rays photo peaks. The results of this method were compared to standard samples ofIAEA-373 and they were found to be in good agreement.

Standardization of the emerging medical positron emitter 89Zr

89Zr is a beta plus and electron capture decaying radionuclide. This paper presents: (1) Absolute standardization by the 4πβ(PC)-γ coincidence method: a new equivalent decay scheme, the mathematical formalism applied to it and the choice of the optimal measurement conditions. (2) Measurements by HPGe gamma-ray spectrometry, to determine the possible impurities, to measure the activity and the relative intensities of the emitted gamma rays. (3) Calibration of the CENTRONIC IG12/20A ionization chamber, by two methods: direct measurement using the absolutely standardized solution and linear least square modelling, as well as their comparison. (4) Comparisons of results of all measurement methods.

Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

Primary radioactivity standardization and gamma intensities determination of 124Sb

A solution containing 124Sb was primarily standardized by the 4πβ−γ coincidence and anticoincidence extrapolation methods in the frame of the EUROMET 907 international comparison organized by Laboratoire National Henri Bequerel (LNHB)/France, in 2007. The main purposes of this exercise are the improvement in the uncertainties on the gamma-ray emission intensities and they clarify the discrepancies verified among the intensity values for many weak gamma rays reported in the literature. In this work the results of the activity obtained were used to determine the absolute and relative gamma-ray intensities using a planar and coaxial HPGe detectors calibrated by 152Eu and 116mHo multi-gamma standard sources covering the energy range from 20 to 1408 keV. Additionally the half-life of 124Sb was determined following the decay of a solution of 124Sb contained in a glass ampoule over a period of three half-lives using two 4πγ ionization chambers.

Highly precise measurements of the relative gamma-ray intensities for 56Mn and 72Ga

Precise relative γ-ray intensities of 56Mn and 72Ga produced by neutron irradiation of natural Mn 3O 4 and enriched 71Ga 2O 3 (99.8%) were measured by an HPGe detector with highly-precisely calibrated detection efficiencies. As both nuclides exhibit no β branch to the ground state, the absolute emission probabilities of the 846.8 keV γ ray for 56Mn and 834.0 keV γ ray for 72Ga were determined to be 0.9888±0.0014 and 0.9553±0.0005, respectively.

Studies on the decays of 153Sm and 153Gd to 153Eu

The relative intensities of x-rays and gamma rays emitted in the decays of 153Sm and 153Gd have been measured precisely using a set of five HPGe and Si(Li) detectors. The intensities of L x-rays from 153Gd and K and L x-rays from 153Sm decays have been measured for the first time. In addition, the level scheme of 153Eu following 153Sm decay was also investigated using high resolution HPGe-HPGe coincidence set-up (2 τ = 7 ns).

Precise measurement of relative gamma ray intensities in the decay of 182Ta

Energies and relative intensities of γ rays in the decay of 182Ta- 182W have been measured precisely using a 64.1 cm 3 Ge(Li) detector. This isotope is suggested as a calibrating source for the efficiency of Ge(Li) detectors in the region from 85 to 300 keV and from 900 to 1400 keV.

Gamma transitions and their relative intensities in153Eu

A careful search for the weak transitions in153Eu nucleus is made following the electron capture decay of153Gd with a high-resolution Si(Li) detector system. Two new transitions with energies 14.07 and 19.8 keV are observed. The energies and relative intensities of different gamma-rays are computed and given.

X-ray and gamma-ray intensity measurements in 210Pb, 177Lu, 170Tm and 141Ce decays

Relative intensities of X-rays and gamma-rays in the decays of 177Lu and 210Pd were precisely measured using a 28.27 mm 2 × 5.0 mm vertical planar HPGe and a 28.27 mm 2 × 5.5 mm vertical Si(Li) detector. The intensities of the X-rays measured in the decays of 177Lu and 210Pb agree reasonably well with the theoretically calculated results. The intensities of K and L X-rays in the decay of 177Lu are measured for the first time. In addition, the revised measured intensities in the case of 141Ce and calculated X- and gamma-ray intensities in the 170Tm and 141Ce decays are also reported.

Precision measurements of X- and gamma-ray intensities in 192Ir, 160Tb, 169Yb and 152Eu decays

The relative intensities of X-rays and gamma-rays in the decays of 192Ir, 160Tb, 169Yb and 152Eu have been measured with better precision using a coaxial 64.1 cm 3 high-purity Ge(HPGe) detector, a 28.27 mm 2 × 5.0 mm vertical plane HPGe detector and a 28.27 mm 2 × 5.5 mm vertical Si(Li) detectors. The intensities of different K and L X-rays in 160Tb decay and different L X-rays in 152Eu and 169Yb decays are measured for the first time. This set of sources can be used for the efficiency calibration of semiconductor detectors over the energy range 5–1400 keV.

X-ray and gamma ray intensity measurements in 141Ce and 170Tm decays

Relative intensities of X-rays and gamma rays in the decays of 141Ce and 170Tm were precisely measured using a 28.27 mm 2 × 5.0 m vertical planar high purity Ge (HPGe) detector and a 28.27 mm 2 × 5.5 mm vertical Si(Li) detector. The intensities of the different X-rays measured in the decays of 141Ce and 170Tm agree reasonably well with the results calculated using the formulation of Verma and Pal [1] in most of the cases. The measured value of the L β1.3.4 X-ray intensity from 141Ce is found to differ considerably from the calculated value, which could be due to wrong values of some of the parameters used in the theoretical calculations.

Precision measurements of gamma-ray intensities VI. 120Sb, 124Sb and 125Sb

Relative intensities of gamma rays in the decays of 120Sb, 124Sb and 125Sb were measured precisely with a calibrated Ge(Li) detector. Experimental errors for strong gamma rays are (0.3–1)%. Relative intensities of gamma rays below 450 keV for 125Eu, 154Eu and 192Ir were also measured. Gamma-ray intensities per decay of these nuclides were determined by using the relative intensities and other decay information.

Precision measurements of gamma-ray intensities IV. Low energy region: 75Se and 133Ba

Relative intensities of gamma rays were measured in Hiroshima and Nagoya in the region of 122–356 keV. Two Ge(Li) detectors were calibrated with four kinds of standard sources and a cascade gamma-ray source. The disintegration rates of the standard sources were determined by means of the coincidence method. Relative intensities of 75Se and 133Ba were obtained with estimated errors less than 1% for strong gamma rays. Gamma-ray intensities per decay were also extracted.

Precision measurements of gamma-ray intensities V. 160Tb, 168Tm and 182Ta

Relative intensities of gamma rays in the decays of 160Tb, 168Tm and 182Ta were precisely measured with a calibrated Ge(Li) detector. Experimental errors for strong gamma rays are 0.5–1%. A few new weak gamma rays for 168Tm and 182Ta were observed. Gamma-ray intensities per decay of three nuclides were derived from each of the relative intensities. These long-lived nuclides which emit multi-gamma-rays are useful for calibration of the gamma-ray spectrometer.

The decay of100Ag

The gamma rays emitted in the decay of sources of 100Ag produced in the 102Pd(p,3n) and 92Mo(12C,p3n) reactions have been studied in singles and coincidence. Comparison of the measured relative intensities of gamma rays from sources produced in the two reactions confirms the existence of two beta-decaying isomers in 100Ag with spins and parities 5+ and 3(+). Decay schemes for the two isomers were constructed on the basis of gamma-gamma coincidences. The half-life of 100Ag was found to be 2.06+or-0.25 min and no difference was found in the half-lives of the two isomers. The decay energy was determined to be 7.17+or-0.25 MeV from studies of positron-gamma-ray coincidences. Measurements of log ft values and gamma-gamma angular correlations allowed the assignment of spins and parities to levels in 100Pb.

Gamma-Ray Spectroscopy of166Er

Relative intensities of gamma rays of 166 Er from the decays of 166m Ho were precisely measured with a calibrated Ge(Li) detector. Errors of relative gamma-ray intensities are about 0.5% for strong gamma rays. Angular correlations for 11 cascades were measured with Ge(Li) and NaI(T1) detectors. The B (E2) ratios were deduced from the relative gamma-ray intensities and the adopted values of the M1 components. These ratios were satisfactorily explained by means of the band mixing treatment between the ground-state band and the gamma-vibrational band.

Gamma-Ray Spectroscopy of 156Gd Following the Decays of 156Eu and 156Tb

Relative intensities of gamma rays of 156 Gd from the decays of 156 Eu and 156 Tb were measured precisely with a calibrated Ge(Li) detector. Errors of relative intensities for strong gamma rays are about 0.5%. Ratios of reduced E 2-trarnsition probabilities in 156 Gd were deduced from the relative gamma-ray intensities. A perturbation band-mixing treatment was applied for the first excited K π =0 + and K π =2 + rotational bands but the B ( E 2) ratios were not satisfactorily explained.

Precision measurements of gamma-ray intensities. II. 152Eu, 154Eu and 192Ir

Relative intensities of gamma rays in the decay of 152Eu, 154Eu and 192Ir were measured precisely with a calibrated Ge(Li) detector. Errors of relative intensities for strong gamma rays are 0.3–0.5%. These multi-gamma-ray sources are useful for the calibration of the Ge(Li) detector. Gamma-ray intensities per decay of 192Ir were derived from the relative intensities.

Precision measurements of gamma-ray intensities I. 56Co, 88Y, 110mAg, 134Cs and 207Bi

To determine relative intensities of gamma rays in the region of 280–2750 keV, Ge(Li) detectors were calibrated with eight kinds of standard sources and four kinds of cascade gamma-ray sources. The disintegration rates of the standard sources were determined by means of the coincidence method. Intensity measurements were performed with two Ge(Li) detector systems. Experimental conditions were improved, especially for source positions and the dead time. The total number of calibration measurements was 437. Gamma-ray spectra were carefully analyzed, and the sum effect was corrected. Relative gamma-ray intensities of 56Co, 88Y, 110mAg, 134Cs and 207Bi were obtained with errors less than 0.5% for strong gamma rays.