Total bremsstrahlung photon yield and Z-dependence in thick targets produced by beta emitter 45Ca and 147Pm (original) (raw)
The total bremsstrahlung photon yield in thick metallic targets (Al, Cu, Sn and Pb) produced by beta emitter Ca and Pm has been measured by using X-PIPS Si (Li) detector in the photon energy region 5-30 keV. The Z-dependence index ‘n’ and yield constant are determined in the photon energy region 5-30 keV. The Z-dependence index ‘n’ values obtained from experimental bremsstrahlung photon distributions shows better agreement with the index ‘n’ values obtained from the modified Elwert factor (relativistic) Bethe-Heitler theory, which includes the polarization bremsstrahlung into ordinary bremsstrahlung. It was observed, that a yield constant shows exponential decaying dependence on photon energy. Further, it has been found that the Z-dependence index ‘n’ values are not constant and decreases with increasing photon energy. The higher ‘n’ values than unity clearly indicates the inadequacy of theoretical models to represent the dependence of spectral shape of total bremsstrahlung on atomi...
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Asian Journal of Chemistry, 2018
The measurements of bremsstrahlung spectral photon energy distributions produced by continuous beta particles in thick targets, particularly at low and medium photon energy region of 5-30 keV, requires a high resolution Si(Li) detector. The earlier measurements of bremsstrahlung [1,2] were made with the ionization chamber, proportional counters and G.M. Counters. Later, various researchers [3,4] have used the NaI (Tl) detectors having high efficiency and more effective to make the measurements of bremsstrahlung at high energies, particularly above photon energy of 30 keV. Numbers of measurements [5-7] were also reported below 30 keV by using Si(Li) detector. In the present measurement, the complete response of the detector taken into account, while measuring the bremsstrahlung spectra. The present measurements were taken to obtain the total bremsstrahlung (BS) spectral photon distribution, produced by the continuous β-particles of 45 Ca in thick metallic targets of Al, Cu, Sn and Pb, in the photon energy regions of 5-30 keV. So, in view of the range of photon
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017
The total bremsstrahlung spectra in the thick targets of lead acetate trihydrate (Pb(CH 3 COO) 2 Á3H 2 O), lead nitrate Pb(NO 3) 2 and lead chloride (PbCl 2) produced by 90 Sr beta particles have been investigated in the photon energy region of 10-100 keV. The experimental bremsstrahlung spectra have been compared with the theoretical models Elwert corrected (non relativistic) Bethe Heitler theory, modified Elwert factor (relativistic) Bethe Heitler theory for ordinary bremsstrahlung and modified Elwert factor (relativistic) Bethe Heitler theory which includes polarization bremsstrahlung in the stripped atom approximation. The experimental results show better agreement with theoretical model that includes polarization bremsstrahlung in stripped approximation in the photon energy region below 30 keV. However, at higher photon energy region 30-100 keV, the theoretical model which describes ordinary bremsstrahlung is more accurate to describe the experimental bremsstrahlung spectra. The experimental results show positive deviations from the entire theoretical models at higher energy end of the spectrum. The results indicate that polarization bremsstrahlung plays important role in the formation of total bremsstrahlung spectra in lead compounds produced by continuous beta particles at low photon energy region of 10-30 keV.
Applied Radiation and Isotopes, 2014
The internal bremsstrahlung spectrum of 35 S beta emitter, in the photon energy region of 1-100 keV. These measurement are taken by using a Si(Li) detector. Theoretical and experimental results are reported in terms of number of photons of energy k per m 0 c 2 per unit photon yield. The Nilsson theory for IB is more accurate than KUB and Lewis and Ford, particularly at high photon energy region.
Applied Radiation and Isotopes, 2015
Internal bremsstrahlung spectrum of 89 Sr, a unique first forbidden beta emitter, is studied. The measurements are taken in the photon energy regions of 1-100 keV with Si(Li) detector. The measured results are deviating from Lewis and Ford theory and are close to the Nilsson theory. The effect of Coulomb field on the IB process for different end point energy sources is investigated. Effect of Coulomb field is more for low energy beta emitter towards the high energy end.
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Total bremsstrahlung spectral photon distribution in thick compound targets of lead chloride (PbCl2), lead acetate tri hydrate (Pb(CH3COO)2.3H2O) and lead nitrate (Pb(NO3)2) produced by 204Tl beta emitter has been investigated theoretically and experimentally in the photon energy region of 10-100 keV. The comparison of theoretical and experimental results reveals that polarization bremsstrahlung plays a vital role in the formation of total bremsstrahlung spectra in the photon energy region 10-30 keV. The experimental results are in agreement with the FmodBH+PB theory that includes polarization bremsstrahlung in the total bremsstrahlung up to 30 keV and beyond this energy region the results are closer to the FmodBH theory. The polarization bremsstrahlung contribution in the total bremsstrahlung in compounds has been observed to decrease with the increase in photon energy and with the decrease in modified atomic number of compounds.
Pramana, 2010
We present new experimental data on thick target bremsstrahlung spectra generated from the interaction of energetic electrons with bulk matter. The 'photon yields' in terms of double differential cross-sections (DDCS) are measured for pure elements of thick targets: Ti (Z = 22), Ag (Z = 47), W (Z = 74) and Pt (Z = 78) under the impact of 10 keV electrons. Comparison of DDCS obtained from the experimental data is made with those predicted by Monte-Carlo (MC) calculations using PENELOPE code. A close agreement between the experimental data and the MC calculations is found for all the four targets within the experimental error of 16%. Furthermore, the ratios of DDCS of bremsstrahlung photons emitted from Ag, W and Pt with those from Ti as a function of photon energy are examined with a relatively lower uncertainty of about 10% and they are compared with MC calculations. A satisfactory agreement is found between the experiment and the calculations within some normalizing factors. The variations of DDCS as a function of Z and of photon energy are also studied which show that the DDCS vary closely with Z; however, some deviations are observed for 'tip' photons emitted from high Z targets.
Analytical model for the bremsstrahlung spectrum in the 0.25–20 keV photon energy range
Spectrochimica Acta Part B: Atomic Spectroscopy, 2004
A model for the bremsstrahlung spectrum is presented in order to cover photon energies below 1.5 keV, since no reliable description for this energy range allows one to take advantage of the information generated by ultra-thin window Si(Li) detectors. Starting from Kramers formula and assessing a large set of experimental spectra, an analytical expression was fitted as a function of atomic number, incidence energy and photon energy. The expression obtained describes properly the bremsstrahlung spectrum for photon energies ranging from 0.25 to 20 keV and atomic numbers between 4 and 83, at beam energies ranging from 5 to 38 keV. Finally, the proposed model is compared to different expressions for the continuum available in the literature. ᮊ
An experimental setup to determine the K-shell photoelectric cross-section of Dy, Ta, Pt and Au atoms was implemented at the Nuclear Analytical Laboratory (LAN) of the InSTEC. Bremsstrahlung photons, produced by 90 Sr-90 Y beta particles hitting a thin Ni converter, were used to irradiate the target under study. A HPGe detector, coupled to standard nuclear instrumentation, collected the incident and transmitted spectra. A sharp decrease in intensity at the K-shell binding energy was observed in the transmitted spectra. The photon beam divergence effects were corrected with a calibration curve calculated with Monte Carlo simulations (MCNPX 2.6). In order to establish accurately the cross section at the K-edge energy, the obtained data was processed by two methods: fitting the total cross section to a sigmoidal function, as well as the cross section branches around the K-edge to the empirical law σ = (A/E) n. The Empirical Law method was introduced in this work to minimize the detector resolution effects. The results were compared with experimental and theoretical values showing the best agreement when the thinner targets were used. For the first time the photoeffect cross section at the K-edge energy for Pt is reported at first time.
Modified atomic number dependence of total bremsstrahlung spectra incompounds
Turkish Journal of Physics
The total bremsstrahlung (BS) generated in compounds of BaCl 2 .2H 2 O, CuCl 2. 2H 2 O, Pb(CH 3 COO) 2 .3H 2 O, PbCl 2 , Pb(NO 3)2 , and CuSO 4 .5H 2 O by 90 Sr was investigated using a Si(Li) detector to determine the dependence of the BS spectra on the modified atomic number (Z mod) of compounds in the photon energy range of 1-100 keV. A continuous decrease in the Z mod dependence of the bremsstrahlung spectra in the energy range of 1-30 keV was observed, followed by a slow increase thereafter, i.e. in the range of 30-100 keV. The stronger Z mod dependence of the spectra at low photon energy was expected to be the result of the high intensity of polarization bremsstrahlung (PB) at low photon
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