Internal Bremsstrahlung Spectrum Research Articles

Internal Bremsstrahlung emission during 32P decay

The aim of this work is to experimentally investigate the role of Internal Bremsstrahlung (IB) in the decay of 32P, a pure β-emitter with end-point energy of 1.71 MeV and half-life of 14.28 days. IB is a continuous electromagnetic radiation occurring in β-decay, that had been widely studied in the past years. Its contribution, even if appreciable, is neglected in Monte Carlo (MC) simulation as well as in dosimetric and radiation protection calculations.Ionization current measurements were carried out using a well ionization chamber and compared with MC simulations, performed in the GAMOS (GEANT4-based Architecture for Medicine-Oriented Simulations) framework. Two experimental data sets of 32P IB spectra, taken from the literature, were used to model the IB photon spectral distribution and to include IB emission as an additional source term in MC calculation.Without IB, MC simulations underestimate up to about −18% the measured exposure, whereas the inclusion of IB according to either of the two spectra lead to differences of +2% or +8%. Consequently, the IB process is relevant for high-energy pure β-emitters such as 32P, and its contribution should be considered in all the dosimetric and radioprotection calculations.

Svd Approximation to the Continuous Internal Bremsstrahlung Spectrum of 14c Isotope

Svd Approximation to the Continuous Internal Bremsstrahlung Spectrum of 14c Isotope

Enhancement of radiation exposure risk from β-emitter radionuclides due to Internal Bremsstrahlung effect: A Monte Carlo study of 90Y case

Employment of β-decaying radionuclides, used in many fields (industrial, clinical, research) requires a correct assessment of the operators’ radiological exposure. Usually, in the dosimetric evaluation, the contribution coming from Internal Bremsstrahlung (IB) accompanying the β-decay is not kept into account; nevertheless, this negligibility does not always appear justified, at least for high-energy β-emitters. By means of Monte Carlo (MC) simulations, we showed how the contribution from IB photons is noteworthy for the evaluation of the overall radiation absorbed dose in the case of 90Y source. We evaluated an increase of the absorbed doses, respectively for a point source and the considered receptacles, up to + 34% and + 60% or + 15% and + 28%, depending on the adopted model of IB spectrum. These results demonstrate the relevance of IB phenomenon in radiation protection estimations and suggest extending future theoretical and experimental studies to other β-decaying radionuclides.

Measurement of the activity and spectrum of internal bremsstrahlung of a 51Cr source

The activity of the 51Cr source in the BEST experiment searching for sterile neutrinos is planned to be determined by measuring the spectrum of internal bremsstrahlung. The measurements of activity and the spectrum of internal bremsstrahlung of point low-activity 51Cr sources with Ge semiconductor detectors are discussed. The accuracy and errors of this measurement method are examined.

Measurement of the spectrum of the internal bremsstrahlung from 51Cr

The activity of the intense artificial neutrino source in the experiment BEST will be determined by measuring of the internal bremsstrahlung (IB) spectrum from 51Cr. The paper describes the measurements of the IB spectrum from unsealed point-like 51Cr source using spectrum recovery method, and the main sources of uncertainties are discussed.

Determination of activity of 51Cr on gamma radiation measurements

A method of determining the activity of intensive distributed -sources on the measurement of the continuous spectrum of radiation, for example the internal bremsstrahlung, is developed. The recurrent formula for reconstructing of a continuous spectrum, registered in a Ge detector, at distorting it in the detector. The method of precise measurements of the spectrum of 51Cr internal bremsstrahlung using two point sources of low activity is described.

Internal bremsstrahlung of strongly interacting charged particles

A universal theoretical model intended for calculating internal-bremsstrahlung spectra is proposed. In this model, which can be applied to describing nuclear decays of various type (such as alpha decay, cluster decay, and proton emission), use is made of realistic nucleus–nucleus potentials. Theoretical internal-bremsstrahlung spectra were obtained for the alpha decay of the 214Po nucleus, as well as for the decay of the 222Ra nucleus via the emission of a 14C cluster and for the decay of the 113Cs nucleus via proton emission, and the properties of these spectra were studied. The contributions of various regions (internal, subbarrier, and external) to the internal-bremsstrahlung amplitude were analyzed in detail. It is shown that the contribution of the internal region to the amplitude for internal bremsstrahlung generated in nuclear decay via proton emission is quite large, but that this is not so for alpha decay and decay via cluster emission. Thus, a process in which strong interaction of nuclear particles affects the internal-bremsstrahlung spectrum if found.

Measuring the activity of a 51Cr neutrino source based on the gamma-radiation spectrum

A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of 51Cr is presented.

Measurement of the internal bremsstrahlung spectrum of a 89Sr beta emitter in the 1–100 keV photon energy regime

The internal bremsstrahlung (IB) spectrum of 89Sr, which is a unique first forbidden beta emitter, is studied in the 1–100keV photon energy regime. The IB spectrum is experimentally measured using a Si(Li) detector, which is efficient in this photon energy regime, and is compared with the IB distributions that are predicted by the Knipp, Uhlenbeck and Bloch (KUB), Nilsson, and Lewis and Ford theories. In the soft energy regime up to 15keV, the measured results are in agreement with all the aforementioned theories. However, from 16–30keV, the experimental results are in agreement with the Lewis and Ford theory, which applies to forbidden transitions, and at higher photon energies, the Nilsson theory best describes the measured results. The differences among the different theories also increase with the photon energy. The effect of the electrostatic Coulomb field on the IB process for beta emitters with different end-point energies is investigated by comparing the ratio of the IB probabilities predicted using the KUB and Nilsson theories for 35S and 89Sr, i.e., soft and hard beta emitters, respectively. The Coulomb effect is shown to be significant in the high photon energy regime and for beta emitters with low end-point energies.

Study of the continuous internal bremsstrahlung spectrum from 204Tl by using singular value decomposition

Internal bremsstrahlung (IB) accompanying the β− decay of 204Tl was measured using a 5.08×5.08cm2 NaI(Tl) detector employing a magnetic deflection method in the range of 10–760keV. A novel approach, the Singular Value Decomposition (SVD), is applied to unfold the raw detector spectrum of 204Tl. Unfolded IB spectrum is compared with the KUB theory. The measured spectrum is found to show fairly good agreement with the KUB theory in the energy range of 100–600keV. The distribution beyond the 600keV takes a positive deviation from the theory.

Studies of internal bremsstrahlung spectrum of 35S beta emitter in the photon energy region of 1–100 keV

The internal bremsstrahlung (IB) spectral photon distribution, produced by soft beta particles of 35S (Wmax=164keV), in the photon energy region of 1–100keV, is measured by using a Si(Li) detector, having high energy resolution and efficiency at low energy region. The measured spectral IB photon distribution is compared with KUB theory and Coulomb corrected IB theories given by Nilsson, and Lewis and Ford. After applying the necessary corrections, the experimental and theoretical IB spectral photon distributions are compared in terms of the number of IB photon of energy k per moc2 per unit photon yield. In the low energy region (below 10keV), the experimental results are in agreement with all the theories. However, in photon energy region of 10–50keV, experimental results are in agreement with Coulomb corrected Nilsson theory only, within the experimental errors. Further, beyond 50keV, the Nilsson theory is more close to the experimental results than the KUB, and the Lewis and Ford theories. Hence, the Nilsson theory is more accurate than the other theories given by KUB and Lewis and Ford, particularly at a high energy end. The experimental results reported here with Si(Li) detector are free from number of ambiguities in earlier measurements reported with NaI(Tl) and HPGe detectors. The present results are indicating a relook into the theoretical considerations, given by different theories, while taking into account the Coulomb corrections for predicting the IB spectrum, particularly at high photon energy region.

Studies on Internal Bremsstrahlung Radiation Accompanying Second Forbidden β-Decay of 36 Cl and 99 Tc

The internal bremsstrahlung (IB) radiation accompanying the β-decay of the second forbidden β- transtionof 36 Cl and 99 Tc sources are Studied. The IB measured using a scintillation -spectrometer. It was analyzed by the variable width peeling-off-method, and then corrected applying the proper corrections. The analyzed and corrected IB spectrum was compared with those calculated according to Monte Carlo simulation and modified KUB calculations(M.KUB).It was found that the present experimental results have a better agreement with the theory than the previous work. Also It was found that the present experimental results are in a better agreement with M.KUB calculations than Monte Carlo simulation. This may be due to that the effect of Coulomb-charge(Z) on the IB process is treated in a more refined manner in M.KUB calculations than Monte Carlo Simulation.The 36 Cl and 99 Tcsources have the same degree of forbiddness but different values of Coulomb charge (Z)and different values of β-endpoint energy( 709 KeV and 292 KeV respectively). Therefore the effects of Coulomb charge (Z) and values of β-endpoint energy on the IB-processare studied. It was found that these effects have a large contribution into IB-spectrum for the sources of larger Coulomb charge (Z) and lower β-endpoint energy , as in the case of 99 Tc-source.

Investigation of internal bremsstrahlung radiation accompanying forbidden β-decay of 169Er and 170Tm

The internal bremsstrahlung (IB) spectrum accompanying the β-decay of the first forbidden β-transitions of 169Er and 170Tm is studied. The IB was measured using a scintillation γ-spectrometer. It was analyzed by the variable width peeling-off-method, and then corrected by applying the proper corrections. The analyzed and corrected IB spectrum was compared with those calculated according to the original theories of Knipp and Uhlenbeck (1936) as well as of Bloch (1936) (KUB), the coulomb corrected theory of Nilsson (1956), Lewis and Ford (1957), and detour transitions of Ford and Martin (1969). Also, a new trial was carried out by applying the shape correction factor C 1 of the first forbidden β-transition suggested by Konopinski and Uhlenbeck (1935, 1941) on the Fermi β-decay theory to the calculated IB based on Nilsson's theory. It is called modified KUB (M.KUB). The experimental results are in a good agreement with the theoretical calculations of forbidden β-transition of Ford and Martin (1969), and M.KUB. It is observed that the Coloumb contribution into IB spectrum is larger for lower β-endpoint energies in case of the sources of same Coulomb charge ( Z) and different β-endpoint energies.

Study of the 35S internal bremsstrahlung spectra by the threshold detector method

The spectra of internal bremsstrahlung accompanying the 35S β decay, have been experimentally studied in the lateral geometry by the threshold-detector method. It is shown that this method can be used to reconstruct continuous spectra.

Deconvolution of continuous internal bremsstrahlung spectra of 32P, 85Kr and 143Pr

AbstractAn efficient method of deconvolution of the internal bremsstrahlung (IB) spectra accompanying the β‐decay in 32P, 85Kr and 143Pr is presented. Experimental data is taken from the literature. The usual experimental values are folded with the response matrix of the detector system, and the Gold iteration technique is employed to deconvolve the detector response function for the continuous IB photon spectra. The response function of the detector is calculated using the peak to total ratio and the energy resolution of the detector. The results of the deconvolved IB spectra along with the theoretical calculations are presented. Copyright © 2007 John Wiley & Sons, Ltd.

UNFOLDING CONTINUOUS PHOTON SPECTRUM EMITTED FROM 90Sr-90Y IN EQUILIBRIUM

This paper presents an experiment with the 2×2 inch NaI(Tl) detector to measure the internal bremsstrahlung of 90 Sr -90 Y in equilibrium beta particle emitters using the beta-stopper method in the range 10–1750 keV. The Gold algorithm is applied to unfold the internal bremsstrahlung spectrum of 90 Sr -90 Y beta source. Unfolded IB spectrum is compared with the KUB theory. There is good agreement between the theory and the unfolded measured spectrum in the energy range below 1000 keV. Beyond this energy, there are discrepancies between the theory and unfolded spectrum.

Internal bremsstrahlung spectra of $beta;$minus; particle emitters using the Monte Carlo method

A Monte Carlo code has been developed which obtains internal bremsstrahlung (IB) spectra accompanying β− particles of β− particle emitters. For the IB spectra of β− particle emitters, a simple formula has been also proposed by using the theory of Knipp, Uhlenbeck and Bloch (KUB). The IB spectra of 1532P, 3786Rb, 3889Sr, 3890Sr, 3990Y, 4399Tc, 69170Tm and 74185W obtained by using this code and the KUB theory were compared with experiments.

Internal bremsstrahlung spectra of β− particle emitters using the Monte Carlo method

A Monte Carlo code has been developed which obtains internal bremsstrahlung (IB) spectra accompanying β − particles of β − particle emitters. For the IB spectra of β − particle emitters, a simple formula has been also proposed by using the theory of Knipp, Uhlenbeck and Bloch (KUB). The IB spectra of 15 32 P , 37 86 Rb , 38 89 Sr , 38 90 Sr , 39 90 Y , 43 99 Tc , 69 170 Tm and 74 185 W obtained by using this code and the KUB theory were compared with experiments.

INTERNAL BREMSSTRAHLUNG SPECTRUM OF204TlIN THE X-RAY REGION

The internal Bremsstrahlung spectrum from204Tl has been measured, using magnetic deflector method, in the X-ray region. The corrected spectral intensity is compared with the Coulomb-corrected KUB theory in the energy region of 10 to 30 keV. The good agreement between experiment and theory in this energy region, suggests that "detour effects" are negligible in the low energy region.

Internal bremsstrahlung endpoint energy of54Mn

For {sup 54}Mn there is a discrepancy between the Q{sub EC} obtained from the endpoint energy of the internal bremsstrahlung (IB) spectrum which accompanies the electron capture decay (Q{sub EC}=1353{+-}8 keV) and that obtained from the accepted mass differences (Q{sub EC}=1377{+-}1 keV). This Q value is needed to deduce the partial-half life of the astrophysically interesting {beta}{sup -} decay of {sup 54}Mn from the recently measured {beta}{sup +} partial half-life. To resolve this discrepancy, we have remeasured the endpoint energy of the IB spectrum, by recording coincidences between the IB and the 835-keV {gamma} ray, both detected in Compton-suppressed Ge detectors. The Q{sub EC} we deduce is 1379{+-}8 keV, in agreement with the accepted mass differences. (c) 2000 The American Physical Society.