Internal bremsstrahlung accompanying non-unique second-forbidden β-decay of 36Cl

The internal bremsstrahlung spectrum accompanying the non-unique second-forbidden β-decay of ³⁶Cl is measured using the magnetic deflection technique. The true IB spectrum is obtained with the help of the inverse of the detector response matrix. The experimental data in the energy interval 80 to 700 keV are compared with the theoretical spectra of Knipp and Uhlenbeck, and Bloch, Lewis and Ford, and Chang and Falkoff. The agreement between the measurement and theory is not good throughout the energy region of the present investigation, though the experimental points are close to the second-forbidden scalar theory of Chang and Falkoff.     

Internal Bremsstrahlung accompanying non-unique second-forbiddenβ-decay of36CL

The inner Bremsstrahlung spectrum (I.B.) associated wih the non-unique second forbidden-transition of³⁶Cl was measured using a single channel NaI (Tl) scintillation spectrometer. After making all the necessary corrections, the experimental results were compared with the corresponding theoretical distributions due to the KUB, Lewis and Ford, Nilsson, Ford and Martin and Chang and Falkoff. Also a comparison with those calculated according to Nilsson theory after applying the shape correction factor (M. KUB) was done. The measured spectrum is found to show fairly good agreement with M. KUB theory and its found to deviate therafter from all five theories.The authors would like to thank Prof. Dr. M. El-Nadi and Prof. Dr. O.E. Badawy for their suggestions, interest and encouragement.     

Internal bremsstrahlung from Pr-143

The internal bremsstrahlung (IB) spectrum of¹⁴³Pr is measured in the energy region from 40 to 830 keV by using a multichannel NaI(Tl) scintillation spectrometer and a standard geometrical set up and corrections are applied for various factors. The measured intensity of IB in the investigated energy region is compared with the corresponding theoretical values of Ford and Martin (direct and detour). The present experimental values of IB are coinciding with the direct theory from 40 to 130 keV while from 130 to 500 keV, they are agreeing fairly well with the detour theory. Above 500 keV, the results are deviating positively even from the detour theory.     

The Internal Bremsstrahlung Accompanying the β-Decay from 185W

The internal bremsstrahlung (IB) spectrum accompanying the β-decay from ¹⁸⁵W radionuclide has been measured. The obtained spectrum was analyzed into its constituting gamma lines taking into account all the proper corrections. The analyzed spectrum was compared with those theoretically calculated. The experimental results for the IB probability were found to be in good agreement with theoretical calculations especially with the shape corrected modified KUB theory of Nilsson up to 357.7 keV.     

Total bremsstrahlung spectra in targets of Al,Ti, Sn and Pb produced by complete absorption of 90Sr β particles

Total bremsstrahlung (BS) spectra in thick targets of Al, Ti, Sn and Pb produced by complete absorption of ⁹⁰Sr β particles (0–546 keV) are reported in the photon energy region of 10–30 keV. The experimental BS spectral photon distributions were compared with the theoretical BS spectral photon distributions obtained from Elwert corrected (non‐relativistic) Bethe–Heitler theory, modified Elwert factor (relativistic) Bethe–Heitler theories for ordinary bremsstrahlung (OB) and the modified Elwert factor (relativistic) Bethe–Heitler theory, which include the polarization bremsstrahlung (PB) into OB in stripped atom approximation. It has been observed that the experimental results are showing better agreement with the modified Elwert factor (relativistic) Bethe–Heitler theory having the contribution of PB at photon energy from 10 to 30 keV. This indicates the importance of PB in BS spectra, while studying the spectral photon distributions produced by continuous β particles having energy range of 0–546 keV in thick metallic targets. Further, it is observed that the contribution of PB into OB increases with increase in atomic number of the target and decreases with increase in photon energy. Copyright © 2010 John Wiley & Sons, Ltd.     

The Internal Bremsstrahlung Accompanying the Electron Capture Decay of 57Co

The internal bremsstrahlung (IB) spectrum accompanying the electron capture decay of ⁵⁷Co have been measured. The measured spectrum was then analyzed into its constituting gamma lines. The proper corrections for the analyzed IB (EC) spectrum have been taken into account. A comparison between the present experimental results of the IB (EC) probability per electron capture and those calculated theoretically according to Martin and Glauber theory have been done. This comparison shows a good agreement throught the investigated range of energy (300 up to 650 keV).     

A study of the 75As(n,n'γ)75As reaction

The de-excitation gammas following the inelastic scattering of neutrons from ⁷⁵As have been studied for incident neutron energies from 1300 to 2800 keV in steps of 100 keV. The energy levels and the branching ratios of their decays have been deduced from excitation function measurements: 58 energy levels have been found in the excitation energy region below 2.8 MeV, twelve of which are reported for the first time in this work. The experimental excitation functions and angular distributions have been compared with the theoretical predictions based on the statistical theory of the compound nucleus. Spin and parity assignments for the levels and multipolarities for the decays are proposed for excitation energies of levels up to 2300 keV.     

Kinetic energy release for the collision-induced dissociation of CO<Superscript>+</Superscript>

The kinetic energy release distributions (KERDs) of C⁺ and O⁺ fragments arising from 5 keV collision-induced dissociation (CID) of CO⁺ ions with helium have been measured. The KERDs of C⁺ and O⁺ exhibit different features corresponding to the states that participate in CID processes. We have identified groups of dissociative and predissociative states, and compare them with theoretical and experimental values.     

Role of polarization Bremsstrahlung in the formation of thick target Bremsstrahlung spectra in the energy range of 5–10 keV

Role of polarization Bremsstrahlung in the formation of total Bremsstrahlung (BS) spectra in thick targets of Al, Ti, Sn and Pb, produced by complete absorption of ⁹⁰Sr beta particles having an energy range of 0–546 keV, are studied in the photon energy region of 5 to 10 keV. The theoretical BS spectral photon distributions, obtained from Elwert corrected (nonrelativistic) Bethe–Heitler theory, a modified Elwert factor (relativistic) Bethe–Heitler theory that describe ordinary Bremsstrahlung (OB) and a modified Elwert factor (relativistic) Bethe–Heitler theory for BS spectra that includes the polarization Bremsstrahlung (PB) into OB in stripped atom approximation, were compared with the experimentally measured BS spectral photon distributions. It has been observed that the experimental results are in agreement with the modified Elwert factor (relativistic) Bethe–Heitler theory at photon energy from 5 to 10 keV. It has been also observed that the contribution of PB into OB decreases with increase in end‐point energy of beta emitter and the energy of the emitted photon. Further, it has been found that the contribution of PB into OB increases with increase in atomic number of the target atom. This indicates the importance of PB in the formation of BS produced by continuous beta particle. Copyright © 2012 John Wiley & Sons, Ltd.     

InternalK-conversion coefficients of transitions in182W

TheK-conversion coefficients of seven low energy transitions (～100–400 keV) in¹⁸²W following the decay of¹⁸²Ta have been determined by the NPG method using the newly reported γ-ray intensities measured by Ge(Li) detectors. The results are compared with theoretical values deduced from the tabulations of Rose, Sliv and Band, and Pauli. The weak peak corresponding to theK-conversion line of the 351.3 keV transition could be observed in accordance with the previous investigations, however the existance of the previously reported 146.3 keV transition could not be confirmed. Also theK-conversion line of the recently reported 110.4 transition could not be observed.     

Investigation of the reaction 35Cl(τ, α)34Cl at Eτ = 15 MeV

The ³⁵Cl(τ, α)³⁴C reaction has been used to study the properties of ³⁴Cl levels up to an excitation energy of 5 MeV. Angular distributions of 37 levels were measured with a split-pole magnetic spectrograph, at a bombarding energy of 15 MeV. New levels have been found at 3847, 3964, 4206, 4321 and 4715 keV, all ± 10 keV. There is a strongly excited multiplet at E_x = 5.0 MeV with components at 4939 ± 11, 4958 ± 11, 4971 ± 11, 4998 ± 12 and 5010 ± 13 keV. A DWBA analysis of the α-particle angular distributions yielded l_n values and spectroscopic factors. New spin and parity assignments were obtained. The T = 1 character of the levels at E_x = 4.21 and 4.72 MeV has been determined. Experimental spectroscopic factors are compared with results from recent many-particle shell-model calculations.     

Fast neutron scattering from rubidium

A study was made of the (n, n), (n, n′), and (n, n′ γ) reactions which occur when a natural rubidium scattering sample is exposed to mono-energetic neutron fluxes of energies ranging from 120 to 1910 keV. Total cross sections, elastic scattering angular distributions and excitation functions for inelastic scattering were measured with a neutron time-of-flight spectrometer. Results are compared with Hauser-Feshbach theory. A 40 cc Ge(Li) detector was used in the time-gated mode to measure γ-rays from the (n, n′ γ) reaction. The latter measurements were used to refine and extend the energy level schemes derived from neutron spectroscopy. Several new levels were discovered in the low-lying (below 1900 keV) energy level spectra of⁸⁵Rb and⁸⁷Rb. Gamma decay schemes and branching ratios were determined for the low-lying levels of⁸⁵Rb and⁸⁷Rb.     

Messung der zirkularen Polarisation der Inneren Bremsstrahlung von90Y

The circular polarization of the Internal Bremsstrahlung (IB) of⁹⁰Y was measured with a Compton polarimeter according to Beard and Rose. The results are compatible with the theoretical predictions of Ford and Martin [8], who include “detour transitions” in their calculations of the circular polarization. Measurements ofΒ-γ-correlations of the IB of⁹⁰Y are discussed, which suggest the consideration of detour transitions too.     

Comparison of cluster and shell model wave functions of deformed32S states

The 786 keV beta-286keV gamma angular correlation in the ground state decay of¹⁴⁹Pm is measured for the first time, using the conventional slow-fast scintillation assembly. Integral correlation results characterize the involved beta transition to be of first-forbidden non-unique type. The present results combined with the other experimental parameters, strongly support a 9/2^? spin-parity character to the 286 keV level in¹⁴⁹Sm. The energy independence of the reduced correlation coefficient as found in this work shows the validity ofξ-approximation for the 786 keV beta transition in¹⁴⁹Pm and is also consistent with the logft value and spectrum shape reported by earlier authors.     

Search for missing predicted high-spin states in28Si

New shell model calculations have predicted several high-spin (I ^π=5⁺ and 6⁺) levels in²⁸Si near 10 MeV excitation energy which are missing from or ambiguous in existing experimental studies. Angular distributions, linear polarizations and Doppler-shifts ofγ-rays have been measured for theγ-decay of theE _p=1,911 and 2,073 KeV resonances of the²⁷Al(p, γ) reaction in an attempt to discover these missing states or confirm the discrepancies between experiment and theory. The excitation energies and spin-parities of the resonances were determined as 13,424.4±0.2 keV,I ^π=5⁺ and 13,582.3±0.5 keV,I ^π=6⁺. States populated in theγ-decay of these resonances were assigned spins and parities as follows: 11,777 keV,I ^π=5⁺; 11,331 keV,I ^π=6⁺; 10,417 keV,I ^π=5⁺; 9,417 keV,I ^π=4⁺ and 8,945 keV,I ^π=5⁺. On the basis ofγ-ray transition rates T=1 is assigned to the 13,424 keV level and T=0 to the 10,417 and 11,777 keV levels. With the new data excellent agreement is achieved between the experimental spectrum of²⁸Si and the new shell model predictions. These data provide evidence for aK ^π=3⁺ rotational band comprised by the 6,276, 6,889, 8,945 and 11,331 keV levels. This band emerges also from the shell model wave functions as do theK ^π=0⁺ bands based on the ground state and the 6,691 keV state.     

A study of the93Nb levels populated via the (n,n′ γ) reaction

De-excitation γ-rays from levels in⁹³Nb up to 2203 keV were observed following inelastic neutron scattering at incident energies between 0.6 and 2.575 MeV. The energy level and decay modes of⁹³Nb are deduced. Spin and parity assignments are based on the comparison of the experimental (n, n′) cross sections with calculated cross sections using Hauser-Feshbach theory corrected for level-width fluctuation corrections. The low-lying levels of⁹³Nb have been studied within the framework of the vibration-particle model to account for their energy and spin assignments, as well as the reduced transition probabilities measured in Coulomb excitation experiments.     

Kernspektroskopische Messungen am Zerfall des202Bi

An experimental investigation of the complex γ-decay of²⁰²Pb following the β-decay of²⁰²Bi is presented. Gamma-ray energies and intensities, conversion coefficients and γ – γ-coincidences were measured using mass separated sources. The results supplement and refine previous studies. In particular the measurements of gamma-ray energies aimed at an accuracy as high as possible in order to get reliable energy relations for the ordering of the γ-transitions in a level scheme. More than 200 γ-transitions were observed. New excited levels of²⁰²Pb are proposed at 2185.0, 2235.4, 2324.9, 2360.4, 2517.3, 2916.5, 3682.2, and 3723.5 keV above the ground state. The spin value I=4 for the 1915.1 keV level of²⁰²Pb is confirmed and to the 2289.2 keV level the spin parity assignment (6)^? is given.     

TheK-conversion coefficient near threshold of the 30 keV isomeric transition in108mAg decay

With calibrated Ge(Li) x-ray detectorsK x rays in the conversion of the 30 keV isomeric transition in the decay of^108mAg were observed in coincidence with 79 keV γ-rays. Thus, the fraction of 30 keV transitions which take place byK conversion was measured to be (2.44±0.23) × 10^?2. Making use of a theoretical total conversion coefficient (K conversion contributes only a minor part of the total conversion coefficient), an experimental value of theK-conversion coefficient was obtained, α_K=(1.07 ± 0.10) × 10⁴ (where the error represents twice the standard deviation to which the error in the detector efficiency has been added linearly). This value agrees with the theory of Hager and Seltzer forM4 conversion. The energy of the cascading γ-ray was remeasured to be 79.20 ± 0.05 keV.     

Decay energy of 55Fe from its inner bremsstrahlung spectrum

Several measurements of decay energy using the inner Bremsstrahlung spectrum (IB) due to radiative electron capture in ⁵⁵Fe has been made. But the results are not uniform. Hence another attempt has been made at the same. Experimental data was obtained with a 4.445 cm. dia × 5.08 cm thick Nal (Tl) detector. It was subjected to suitable statistical treatment and various corrections using Liden and Starfelt procedure. The corrected spectrum agrees well with the Glauber and Martin theory for 1s electron capture beyond 100 keV. From the Jauch plot, the decay energy of 232.36±0.64 keV was obtained.