Response function of NaI(Tl) detectors and multiple backscattering of gamma rays in aluminium

Sabharwal, Arvind D.; Singh, Manpreet; Singh, Bhajan; Sandhu, B.S.

doi:10.1016/j.apradiso.2008.03.006

Cited by 23 publications

(26 citation statements)

References 16 publications

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“…On the other hand, number of multiply scattered events decreases with increasing energy of incident photons because the penetration of gamma ray photons increases with increase in incident energy. This behaviour is in agreement with experimental results obtained from the works of Sabharwal et al [1,3,6,14]. The values of the saturation thicknesses, being compared with experiment and MCNP [2], are presented in Table I.…”

Section: Resultssupporting

confidence: 89%

Evaluation of Multiple Backscattering and Saturation Thickness of Gamma Rays

Tarim

2016

Acta Phys. Pol. A

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A Monte Carlo code was written to determine the saturation thickness for multiply scattered gamma rays from aluminium targets. Interactions of incident gamma rays with the energies of 123, 279, 360, 511, 662, 1115, and 1250 keV were simulated. This work aims to design a convenient code which can be used in investigations on gamma backscattering. Obtained results for saturation thickness values have been compared with experimental ones and the Monte Carlo N-particle (MCNP) code results, and showed good agreement. Also, based on the similar behavior of number of multiple scattered photons between these three methods, the expected spectrum of singly or multiply scattered photons which is not possible to observe with experiment has been presented.

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Section: Resultssupporting

confidence: 89%

Evaluation of Multiple Backscattering and Saturation Thickness of Gamma Rays

Tarim

2016

Acta Phys. Pol. A

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“…In the experimental arrangement 7,8 small isotropic radioactive sources (sealed in the form of thin disks in which the position of source was ≈ 1 mm inside the shielding) of 203 Hg, 51 Cr, 22 Na, 137 Cs and 65 Zn of order of micro curies are placed adjacent to the surface of the target (different elements and alloys). The backscattered radiations are detected by a properly shielded NaI(Tl) scintillation detector.…”

Section: Experimental Set-up and Methods Of Measurementsmentioning

confidence: 99%

“…To evaluate the true scattered spectrum for each thickness, the spectra are taken with and without the target in the primary incident beam. In order to determine the contribution due to multiply backscattered photons only, the spectrum of singly backscattered photons is reconstructed analytically, described in detail in our recent work 7 . The subtraction of this reconstructed normalized singly backscattered spectrum from the observed experimental spectrum provides the numbers of multiply backscattered photons under the full energy peak.…”

Section: Experimental Set-up and Methods Of Measurementsmentioning

confidence: 99%

“…The problem is to quantitatively calculate the numbers of multiply backscattered gamma photons from the finite slabs of investigated samples. Our measurements 7,8 provide Z-dependence of saturation thickness along with the survey of analytical and Monte Carlo simulation approaches to study the multiple backscattering, and available experimental data on these processes. The reported experimental data provide useful information about intensity and energy distributions of gamma rays experimentally backscattered from various materials as a function of primary gamma radiation energy.…”

Section: Introductionmentioning

confidence: 99%

“…The present measurements provide saturation thickness of gamma rays of various energies multiply backscattered from the targets of elements and alloys. The response function of NaI(Tl) detector obtained in our earlier work 7 employs an inverse matrix approach, and it does the required spectrum unfolding.…”

Section: Introductionmentioning

confidence: 99%

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Investigations of energy dependence of saturation thickness of multiply backscattered gamma photons in elements and alloys - an inverse matrix approach

Sabharwal

Sandhu

Singh

2011

J. Phys.: Conf. Ser.

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Abstract. In Compton scattering experiments employing thick targets one observes that the numbers of multiply backscattered photons increases with increase in target thickness and then saturate at a particular target thickness called the saturation thickness. The energy of each of gamma ray photons continues to decrease as the number of scatterings, the photon undergoes, increases in the sample having finite dimensions. The present experiment is an independent study of energy and intensity distributions of 279-, 320-, 511-, 662 keV, and 1.12 MeV gamma rays multiply backscattered from targets of different atomic numbers and alloys of various thicknesses, and are carried out in a backscattering geometry. The backscattered photons are detected by a NaI(Tl) scintillation detector. The detector response unscrambling, converting the observed pulse-height distribution to a true photon energy spectrum, is obtained with the help of a 12x12 inverse response matrix. The present experimental results confirm that for thick targets, there is significant contribution of multiply backscattered radiations emerging from the targets, having energy equal to that of singly scattered Compton process. The measured saturation thickness (in units of mean free path) for multiply backscattering of gamma photons is found to be decreasing with increase in energy of incident gamma photons.

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