Precise measurement of energy of the first excited state of 115Sn (Eexc = 497.3 keV)

Single beta decay of 115In to the first excited level of 115Sn (Eexc = 497.3 keV) is known as beta decay with the lowest Q value. To determine the Q precisely, one has to measure very accurately the Eexc value. A sample of tin enriched in 115Sn to 50.7% was irradiated by proton beam at the U-120 accelerator of INR, Kyiv. The 115Sb radioactive isotope, created in 115Sn(p,n)115Sb reaction, decays with T1/2 = 32 min to 115Sn populating the 497 keV level with ~ 96% probability. The total statistics of ~ 10^5 counts collected in the 497 keV peak in series of measurements, exact description of the peak shape and precisely known calibration points around the 497 keV peak allowed to obtain the value Eexc = 497.342(3) keV, which is the most precise to-date. This leads to the following Q* value for the decay 115In to 115Sn*: Q* = 147 +- 10 eV.Comment: 6 pages, 3 figure

Isomer ratios and mean angular momenta of photonuclear reaction products

Isomer ratios and mean angular momenta are obtained both for photofission products of 237Np, 238U and for nuclei 122,120m,gSb and 117m,gIn. Photonuclear reactions 121Sb(γ,n)120m,gSb, 123Sb(γ,n)122m,gSb, 118Sn(γ,p)117m,gIn were studied in the last cases. The technique of gamma-ray spectrometry for isomeric ratio determination was used. Target nuclei were irradiated by bremsstrahlung spectrum of microtron M-30. Comparison of isomer ratios calculated by Empire II code with experimental data was performed. Effects of the nuclear structure model parameters on values of isomer ratios are discussedДосліджено ізомерні відношення та визначено середні кутові моменти для продуктів фотоділення ядер 238U і 237Np, а також виміряні ізомерні відношення для ядер 120,122m,gSb и 117m,gIn в реакціях (γ,n) та (γ,p). Опромінення проводилося гальмівними γ-квантами мікротрону М-30 з максимальною енергією спектру 16 та 15 МеВ. Досліджено залежності ізомерних відношень від кутових моментів збуджених ядер з використанням програми Empire II для розрахунку характеристик ядерних реакцій.Измерены изомерные отношения и извлечены средние угловые моменты для продуктов фотоделения ядер 238U и 237Np, а также измерены изомерные отношения для ядер 120,122m,gSb и 117m,gIn в реакциях (γ,n) и (γ,p). Облучение проводилось тормозными γ-квантами микротрона М-30 с максимальной энергией спектра 16 и 15 МэВ. Исследованы зависимости изомерных отношений от угловых моментов возбужденных ядер с использованием программы Empire II для расчета характеристик ядерных реакций

Investigation of Nuclei Properties in Region Z=40 and Interaction Thereof with Nuclear Shell

Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Investigation of (γ,p)-reactions on zirconium and molybdenium nuclei

The flux-weighted average yields of the 92Mo(γ,p)91mNb, 96Mo(γ,p)95Nb, 97Mo(γ,p)96Nb, 98Mo(γ,p)97Nb, 94Zr(γ,p)93Y, 91Zr(γ,p)90mY and 92Zr(γ,p)91mY reactions were measured for the first time at an bremsstrahlung end-point energy of 20 MeV. They are equal 10,700(1600), 1920(200), 708(70), 980(100), 1067(187), 85(8) and 143(15) µb, respectively. It is shown that the semi-direct mechanism, which is taking into account the isospin splitting of the giant dipole resonance makes a much greater contribution to the mechanisms of the above reactions than the statistical one calculated using the TALYS-1.9 code

Non radiochemical technique for

Nondestructive methods of 90Sr determination were developed for small biological objects, such as small rodents, to keep biological object going for further research even in presence of essential contamination of the same object by 137Cs. To carry out 137Cs input registration in proper way, we used 2 different methods: a) The method of Cs and Sr electrons filtering using thin filters with subsequent measurement of residual Y-spectrum. Comparative results of measurements for calibrated and studied samples were found not hard to obtain the amount of 90Sr. Obtained result is close to the real one if the ratio between Cs and Sr is comparable. In opposite case the method requires several measurements depending on 137Cs/90Sr relation b) Method of beta-gamma spectrometry with specially elaborated beta-gamma spectrometer and corresponding software. General distinction of this spectrometer from the standard one is using the special procedure of experimental spectrum operation, and the use of thin (~1mm and 0,1mm) scintillator as a detector that allows to have the effectiveness of registration of gamma quanta of 661 keV in one-two orders less than for electrons with the same energy. The experimental spectrum operation was realised by the method of inserting into one of the calibrated spectrums, which had been measured on the same spectrometer from specially fabricated phantoms of mice with known contents of 137Cs and 90Sr+90Y. Method provides contemporary content of 90Sr and 137Cs. Procedure of standard radiochemical determination for 90Sr contents conducted in 13 mice on the final stage of studies has confirmed the method reliability

Precise energy measurements of the first-excited state in

The energy of the first-excited state in 197Au has been measured with high precision using conventional γ-ray spectroscopy with HPGe detectors. A γ77 keV line of 197Au and Kβ lines of Au are overlapped almost completely and such measurements present a very serious challenge. The coincidence measurements have been applied, first, with the γ77 keV line for the precise energy calibration using Kα and Kβ lines of Au, secondly, with Kα lines of Au for the precise energy measurement of the first-excited state in 197Au. Our current result is 77.339± 0.003 keV, confirming the observations of the recent 197Au NEET experiment performed at SPring-8, while, according to available nuclear data, the energy of the first-excited state in 197Au is 77.351±0.002 keV

180mTa excitation by positrons

For the first time the 180mTa excitations cross-sections have been measured at the photonless annihilation of the positrons. The effective cross-sections have been obtained: σef(180mTa) = (4,0 ± 1,0) · 10-25 cm2, and σef(180mTa) = (1,7 ± 0,3) · 10-27 cm2 for the end point energies of the positrons about: 3,9 and 1,0 MeV, accordingly. From the effective cross-sections, the differential cross-sections σph have been calculated. The value of the differential crosssections considerably differs from the existing theoretical calculations. The comparison of the integral cross-sections dependence both the photonless annihilation and (γ γ')-reaction with bremmsstrahlung photons from energy was done. The correlation of the experimental data was shown

Anomalous internal conversion of the K-forbidden 55 keV E1-transition in

The precise γ-ray intensities of the transitions following the decay of the 160.44 day isomeric state in 177Lu have been measured by using four different types of semiconductor photon detectors. The values of the internal-conversion coefficient and penetration parameter λ1 for E1-transition with the energy of 55 keV were determined from intensity balance of 21/2− 1260 keV level in 177Hf

Excitation of

For the first time the flux-weighted average yields of $$^{\mathrm{180}}\hbox {Hf}^{\mathrm{m}}$$ in ($$\gamma$$,p)-reaction were measured at the bremsstrahlung end-point energies of 20, 40 and 55 MeV, respectively by activation and off-line $$\gamma$$-ray spectrometric technique. The comparison of the theoretical with using of the TALYS-1.9 code and the experimental yields demonstrates the dominance of non-statistical processes. Considering of the isospin splitting for the semi-direct mechanism shows qualitative agreement of the experimental and calculated data