Beta response of CaSO4:Dy based thermoluminescent dosimeter badge and its angular dependence studies for personnel monitoring applications

Munish Kumar; RB Rakesh; C Sneha; P Ratna; AK Bakshi; D Datta

doi:10.4103/0972-0464.194959

Users Online: 143

ORIGINAL ARTICLE

Year : 2016 | Volume : 39 | Issue : 3 | Page : 132-137

Beta response of CaSO₄:Dy based thermoluminescent dosimeter badge and its angular dependence studies for personnel monitoring applications

Munish Kumar, RB Rakesh, C Sneha, P Ratna, AK Bakshi, D Datta
Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India

Date of Web Publication

30-Nov-2016

Correspondence Address:
Munish Kumar
Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai - 400 085, Maharashtra
India

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/0972-0464.194959

Abstract

Studies on the response of 0.4 mm and 0.8 mm thick Teflon embedded CaSO₄:Dy discs are carried out using different beta sources having energy ranging from 0.224 to 3.54 MeV. Angular dependence of the response for 0.4 and 0.8 mm thick thermoluminescence (TL) discs was also studied for ⁸⁵ Kr and ⁹⁰ Sr/⁹⁰ Y beta sources. The ratio of the response of the open disc to that under 1.5 mm thick Perspex filter (D_Open/D_Perspex) was estimated for 0.4 and 0.8 mm thick TL discs in the energy range from 0.689 to 3.54 MeV. The evaluation of (D_Open/D_Perspex) ratio is necessary as same is used to estimate the energy of beta particles and to apply appropriate correction factor while evaluating beta dose. In addition to above, the optical density and transmission characteristics for 0.4 and 0.8 mm thick Teflon and CaSO₄:Dy Teflon embedded discs are also reported.

Keywords: Angular dependence, beta dose estimation, beta secondary standard calibration setup, D_Open/D_Perspexratios, energy response, personnel monitoring, thermoluminescence glow curve

How to cite this article:
Kumar M, Rakesh R B, Sneha C, Ratna P, Bakshi A K, Datta D. Beta response of CaSO₄:Dy based thermoluminescent dosimeter badge and its angular dependence studies for personnel monitoring applications. Radiat Prot Environ 2016;39:132-7

How to cite this URL:
Kumar M, Rakesh R B, Sneha C, Ratna P, Bakshi A K, Datta D. Beta response of CaSO₄:Dy based thermoluminescent dosimeter badge and its angular dependence studies for personnel monitoring applications. Radiat Prot Environ [serial online] 2016 [cited 2023 May 30];39:132-7. Available from: https://www.rpe.org.in/text.asp?2016/39/3/132/194959

Introduction

For beta particles, there is rapid attenuation in traversing a relatively thin layer of matter. The beta energy loss per unit path length (dE/dx) is a strong function of the beta energy, with the energy deposition greatest near the end of the path. Typical thermoluminescence (TL) dosimeters having a thickness less than the range of the beta radiations act as dE/dx detectors as required by the definition of skin dose whereas thick dosimeters act as total absorption detectors. Hence, to make dE/dx independent of the energy of beta particles, the detector thickness must be small as compared with the ranges of all the electron energies of interest. In addition, a thick dosimeter calibrated using gamma/photon sources say ¹³⁷ Cs or ⁶⁰ Co will yield a beta dose that is averaged over the thickness of the dosimeter.^[1] The beta response of TL dosimeters has earlier been investigated by various researchers.^{[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13]}

At present in India, CaSO₄:Dy Teflon embedded TL discs having a thickness of 0.8 mm are used for personnel monitoring applications.^[6] The TL signal for these discs is recorded using hot gas thermoluminescent dosimeter (TLD) badge reader which utilizes clamped/exponential heating profile. The clamping temperature is ~285°C, and the luminescence is recorded for 30 s. As there are three discs in the presently used TLD badge, the processing time per badge is ~100 s.^[14],[15] Efforts have been made to reduce the recording time of the TL glow curve by reducing the disc thickness from 0.8 to 0.4 mm and same may improve the beta response as well.

The present paper also investigates the advantages of the 0.4 mm thick TL dosimeters for their use in personnel monitoring applications. Since the optical transmission of the discs depend on the composition of the phosphor and Teflon mixture as well as on disc thickness, the optical density (OD) of the disc becomes an important parameter, and same was measured. In addition to above, the beta response of 0.4 mm thick CaSO₄:Dy Teflon embedded discs was studied and compared with the beta response of 0.8 mm thick TL discs. The irradiations were carried out using PTB beta secondary standard calibration setup (BSS2) which has three beta sources, namely ¹⁴⁷ Pm (E_max ~ 0.224 MeV),⁸⁵ Kr (0.689 MeV), and ⁹⁰ Sr/⁹⁰ Y (2.28 MeV).^{[16],[17],[18]} Studies were also carried out with ²⁰⁴ Tl (0.764 MeV),³² P (1.71 MeV), natural uranium (2.30 MeV), and ¹⁰⁶ Ru/¹⁰⁶ Rh (3.54 MeV) beta sources.

In view of better beta energy response as well as the short time required to record the TL glow curves, studies were performed with 0.4 mm thick CaSO₄:Dy Teflon embedded TL discs based badge. The response of 0.4 mm and 0.8 mm thick CaSO₄:Dy (TL) discs under 1.5 mm thick Perspex filter was studied and compared with the response of the open disc. This was necessary as the ratio of the response of the open disc to the response under filter is used to estimate the average energy of beta particles which is used to apply correction factor while evaluating beta dose/design of dose estimation algorithms.^{[7],[8],[13],[19]} The angular dependence of the response of 0.4 and 0.8 mm thick discs based TL badge was also studied for ⁸⁵ Kr and ⁹⁰ Sr/⁹⁰ Y beta sources. These studies will be useful to design and improve the beta dose evaluation algorithm for personnel monitoring performed using CaSO₄:Dy based TLD badge.

Materials and Methods

CaSO₄:Dy Teflon embedded TL discs used in the present study were of thickness 0.4 mm (100 mg/cm ²) and 0.8 mm (200 mg/cm ²) and both have a diameter of 13.3 mm. The mass of 0.4 and 0.8 mm thick discs was 140 and 280 mg, respectively. The maximum variation in sensitivity of 0.4 and 0.8 mm thick CaSO₄:Dy TL discs used in the present study was within ± 5%. [Table 1] gives various details of the 0.4 mm and 0.8 mm thick TL discs. For the measurement of OD of CaSO₄:Dy discs (0.4 mm as well as 0.8 mm thick), well-calibrated Gammasonics densitometer (Model 301X) was used which has a high-efficiency silicon photodiode as a light detector. Moreover, the OD for 0.4 and 0.8 mm thick discs made only from Teflon was also measured. This was carried out to check the increase in OD after addition of phosphor to Teflon. The exposed CaSO₄:Dy Teflon embedded TL discs (0.4 and 0.8 mm thick) were read using a well-calibrated hot gas TLD badge reader which records TL by heating the disc to ~285°C (clamping temperature) using nitrogen gas. The hot gas TLD based reader used has bialkali photomultiplier tube as a light detector.^[14] The recording time of the glow curve for 0.8 and 0.4 mm thick CaSO₄:Dy Teflon embedded TL discs was 30 and 15 s, respectively. All TL measurements were carried out after 5 days following irradiation.

Table 1: Details about 0.4 and 0.8 mm thick CaSO₄:Dy Teflon embedded thermoluminescence discs

Click here to view

Dosimeters were irradiated using PTB BSS2, which contains three beta sources, namely ¹⁴⁷ Pm,⁸⁵ Kr, and ⁹⁰ Sr/⁹⁰ Y and details are given in [Table 2]. Various beta doses in the range from 1 to 500 mSv were delivered to the TLD cards having 0.4 and 0.8 mm thick discs and response was studied. During irradiations, the dosimeters were backed by Perspex phantom having dimensions of 30 cm × 30 cm × 5 cm and dosimeters were kept perpendicular to the irradiation beam unless otherwise mentioned. All dose deliveries were carried out at 30 cm distance from source except for ¹⁴⁷ Pm for which distance between source and dosimeter was kept at 20 cm. Flattening filters as supplied by PTB were used during studies with ¹⁴⁷ Pm,⁸⁵ Kr, and ⁹⁰ Sr/⁹⁰ Y beta sources. Angular dependence of the response of the TL badge based on 0.4 and 0.8 mm thick TL discs was studied only for ⁸⁵ Kr and ⁹⁰ Sr/⁹⁰ Y beta sources.

Table 2: Details about various beta sources in beta secondary standard-2 calibration set up

Click here to view

In addition to above, the TLDs were also irradiated to photons from ¹³⁷ Cs source under free in air geometry. The distance between source and dosimeter was 50 cm and 3 mm Perspex build-up was used during irradiation to establish electronic equilibrium. The response of different beta energies relative to the response at 662 keV photons emitted from ¹³⁷ Cs was also measured. Moreover, the response of 0.4 and 0.8 mm thick CaSO₄:Dy (TL) discs under 1.5 mm thick Perspex filter (D_Perspex) was studied and compared with the response of the open disc (D_Open) for ⁸⁵ Kr and ⁹⁰ Sr/⁹⁰ Y beta sources. The (D_Open/D_Perspex) ratio was also estimated for ²⁰⁴ Tl,³² P, natural uranium, and ¹⁰⁶ Ru/¹⁰⁶ Rh beta sources. No flattening filters were used during studies with ²⁰⁴ Tl,³² P, natural uranium, and ¹⁰⁶ Ru/¹⁰⁶ Rh beta sources; however, the distance between the source and TLD badge was 30 cm.

Results and Discussion

The OD value [Table 3] of 0.4 and 0.8 mm thick Teflon embedded CaSO₄:Dy discs was found to be 0.37 ± 0.02 and 0.64 ± 0.05, respectively. Moreover, the OD values for pure Teflon discs having a thickness of 0.4 and 0.8 mm was found to be 0.20 ± 0.01 and 0.35 ± 0.02, respectively. From [Table 3], it is seen that 0.4 and 0.8 mm thick Teflon embedded CaSO₄:Dy discs have transmission values (at room temperature) of 43% and 23%, respectively, whereas the transmission for pure Teflon disc having a thickness of 0.4 and 0.8 mm are ~63% and 45%, respectively. It should be noted that the OD or transmission values given above are at room temperature; however, during the recording of luminescence signal, the disc temperature can be as high as 240°C at which the transmission of discs is expected to be higher than the values given in [Table 3].

Table 3: Optical density values for 0.4 and 0.8 mm thick Teflon and Teflon embedded CaSO₄:Dy thermoluminescence discs

Click here to view

The relative response of 0.4 and 0.8 mm thick CaSO₄:Dy Teflon embedded discs for different beta ray energy sources;¹⁴⁷ Pm,⁸⁵ Kr, and ⁹⁰ Sr/⁹⁰ Y with respect to ¹³⁷ Cs photons was found to be ~6%, 44%, and 100% and ~4%, 35%, and 100%, respectively [Figure 1]. Summary of the responses of 0.4 mm and 0.8 mm thick discs is given in [Table 4]. The relative response of these TLDs for ¹⁴⁷ Pm is small (≤6%) because the maximum range of beta particles emitted from ¹⁴⁷ Pm is 40 mg/cm ² which is much smaller than the thickness of the 0.4 mm (100 mg/cm ²) as well as 0.8 mm thick (200 mg/cm ²) TL discs. Moreover, for 0.4 mm thick CaSO₄:Dy Teflon embedded discs, the relative response for ⁸⁵ Kr beta particles is better than the response of 0.8 mm thick TL discs although its value is ~45%. The relative response of 0.4 mm thick CaSO₄:Dy Teflon embedded discs is ~12% more as compared to 0.8 mm thick TL discs for ⁸⁵ Kr beta energies. For ⁹⁰ Sr/⁹⁰ Y beta energies, the relative response of 0.4 mm as well as 0.8 mm TL discs is 100%, i.e., response is independent of energy. It should be noted that the response of 0.4 mm thick CaSO₄:Dy Teflon embedded discs is energy independent beyond ~1.6 MeV (E_max), whereas for 0.8 mm thick TL discs the response is energy independent at energy ≥2.0 MeV. The trend of the results reported in [Figure 1] is similar to the work performed by earlier researchers.^{[5],[6],[14],[20]}

Figure 1: Relative response (with respect to ¹³⁷Cs photons) for 0.4 and 0.8 mm thick CaSO₄:Dy discs to various beta energies

Click here to view

Table 4: Relative response (%) of 0.4 and 0.8 mm thick thermoluminescence discs to various beta sources

Click here to view

The angular dependence of the response of TLD badge based on 0.8 mm and 0.4 mm thick TL discs was studied for ⁹⁰ Sr/⁹⁰ Y beta source from 0° to ± 60° in the step of ± 15°. It has been found that for TLD badge based on 0.8 mm and 0.4 mm thick TL discs, the response decreases with increase of the angle of incidence and at ± 60°, the response comes down by ~50% with respect to the response at 0°, i.e., by a factor of 2 for ⁹⁰ Sr/⁹⁰ Y beta particles [Figure 2]a. Similarly for ⁸⁵ Kr, the angular dependence of the response of TLD badge based on 0.8 mm and 0.4 mm thick TL discs was studied. It has been found that for 0.8 mm thick discs the response decreases by ~33% at ± 60° compared with the response at 0°, i.e. the response decreases by a factor of ~1.50 [Figure 2]b. For 0.4 mm thick discs, the response decreases by ~45% at ± 60° compared with the response at 0°, i.e., the decrease in response is by a factor of ~1.8 [Figure 2]b.

Figure 2: (a) Angular dependence (relative) of the response of 0.8 mm and 0.4 mm thick CaSO₄:Dy Teflon embedded discs to ⁹⁰Sr/⁹⁰Y. Beta dose of 5 mSv was delivered. (b) Angular dependence (relative) of the response of 0.8 mm and 0.4 mm thick CaSO₄:Dy Teflon embedded discs to ⁸⁵Kr. Beta dose of 30 mSv was delivered

Click here to view

The angular dependence of the TLD badge based on 0.4 and 0.8 mm thick TLD discs results from the presence of two competing effects.^[10] One is from the variation of the electron fluence which tends to reduce the TL signal and the other effect arises from the variation of the electron path in the detector and tends to increase the signal. It must be noted that with variation in angle (θ) of irradiation, the same beam impinging on the dosimeter at normal incidence is distributed over a wider region and the electron fluence decreases as cos (θ). This is a major factor in decreasing the TL response although the second factor tends to increase the response to some extent. Due to these two competing effects, the decrease in response is relatively slow initially at lower angles of irradiation as compared to the decrease in response at higher values of angles of irradiation. Other factors such as air scattering, beam divergence, attenuation, and backscattering in the source casing, etc., also play an important role in beta dosimetry.

The ratio of the response of the open disc to that under 1.5 mm thick Perspex filter (D_Open/D_Perspex) as is currently used in TLD personnel monitoring badge in India was estimated in the energy range from 0.689 to 3.54 MeV for TLD badges based on 0.4 and 0.8 mm thick TL discs. The (D_Open/D_Perspex) ratios for different beta sources having energy in the range from 0.689 to 3.54 MeV is given in [Table 5] for TLD badges based on 0.4 and 0.8 mm thick TL discs. It may be noted from [Table 5] that (D_Open/D_Perspex) ratio varies from 182 to 1.49 for 0.8 mm thick TL discs whereas for 0.4 mm thick TL discs, the ratio varies from 122 to 1.46. Same is also depicted in [Figure 3]. It may be noted from the field data that the (D_Open/D_Perspex) ratio rarely exceeds 10 in a mixed field of low and high energy beta particles.^[13] The (D_Open/D_Perspex) ratios are lower for TLD badge based on 0.4 mm discs as compared to the badge based on 0.8 mm thick discs as 0.4 mm thick discs have slightly better energy response to beta particles. The angular dependence of the (D_Open/D_Perspex) ratio for ⁹⁰ Sr/⁹⁰ beta source was investigated and is shown in [Figure 4]. It has been found that the (D_Open/D_Perspex) ratio increases from ~1.60 at 0° to ~3.75 at ± 60° for 0.4 mm as well as 0.8 mm thick TL disc based badges. The study also showed that the (D_Open/D_Perspex) ratio for ¹⁰⁶ Ru/¹⁰⁶ Rh beta source increases from ~1.45 at 0° to ~2.0 at ± 60° for TLD badges based on 0.4 mm as well as 0.8 mm thick TL discs.

Table 5: D_Open/D_Perspex ratio for 0.4 and 0.8 mm thick Thermoluminescent dosimeter badges for various beta sources

Click here to view

Figure 3: Variation of D_Open/D_Perspexratio for 0.4 and 0.8 mm thick CaSO₄:Dy discs to various beta sources/energies. D_Perspexrepresents response of 0.4 and 0.8 mm thick discs under 1.5 mm thick Perspex filter, whereas D_Openrepresents the response of open thermoluminescence disc

Click here to view

Figure 4: Angular dependence of D_Open/D_Perspexratio for 0.4 and 0.8 mm thick CaSO₄:Dy discs to ⁹⁰Sr/⁹⁰Y beta source

Click here to view

In view of the energy dependent response of 0.4 and 0.8 mm thick based TLD badges, the beta dose response correction/multiplication factors for different beta sources are required and same is given in [Figure 5]. This factor plays an important role in the evaluation of beta dose. Moreover, for 0.4 mm thick discs, the response is energy independent beyond 1.6 MeV whereas for 0.8 mm thick discs, the response becomes energy independent beyond the beta energy of 2.0 MeV. It may also be noted that no correction factors are required for beta energies beyond which the response of the dosimeter is energy independent. However, the angular dependence of the response of the TLD badges further needs to be compensated, and beta dose correction factors are required even for energy range in which dosimeter exhibits energy independent response. In view of this, the typical values of the beta dose correction factors for ⁸⁵ Kr beta particles is in the range from 2.85 to 4.05 and 2.28 to 3.23, respectively, for 0.8 and 0.4 mm thick TL discs. In addition, the beta dose correction factor for ⁹⁰ Sr/⁹⁰ Y beta particles is in the range from 1.0 to 2 for 0.4 mm as well as 0.8 mm thick discs based TLD badges. It may also be noted that response correction is a must in field conditions as the radiation workers are generally exposed at an oblique irradiation angles and at various distances from the source. Hence, for (D_Open/D_Perspex) ratios having values in the range from 1.4 to 4.0, beta dose correction factor having value 1.0 to 2.0 may be appropriate, and this covers beta sources having energy E_max from ~(1.6 to 3.6) and ~(2.0 to 3.6) MeV, respectively, for 0.4 and 0.8 mm thick disc based TLD badge. For (D_Open/D_Perspex) ratios having values >4.0, beta dose correction factor having values of ~3.25 and ~4.05 may be appropriate for 0.4 mm and 0.8 mm thick disc based TLD badge.

Figure 5: Beta dose correction/multiplication factor for different beta energies/sources. In the inset, the curve fitted using single decaying exponential is shown

Click here to view

Conclusions

The OD values for 0.4 and 0.8 mm thick CaSO4:Dy embedded Teflon TLD discs were found to be 0.37 and 0.64, respectively, whereas the corresponding OD values for 0.4 and 0.8 mm thick Teflon discs were 0.20 and 0.30
The relative responses of 0.4 and 0.8 mm thick CaSO₄:Dy embedded Teflon discs for ¹⁴⁷ Pm,⁸⁵ Kr and ⁹⁰ Sr/⁹⁰ Y beta-ray sources were found to be ~6%, 44%, and 100% and ~4%, 35%, and 100%, respectively
The response to beta particles decreases with the increase of the angle of incidence and at ±60°, the response comes down by a factor of 2 for ⁹⁰ Sr/⁹⁰ Y beta particles for TLD badge based on 0.4 and 0.8 mm thick discs. For ⁸⁵ Kr beta particles, the response comes down by a factor of ~1.5 for TLD badge based on 0.8 mm thick discs, whereas the response for 0.4 mm thick discs come down by a factor of ~1.8
For (D_Open/D_Perspex) ratios having values in the range from 1.4 to 4.0, beta dose correction factor having value 1.0 to 2.0 may be appropriate whereas for (D_Open/D_Perspex) ratios having values >4.0, beta dose correction factor having values of ~3.25 and ~4.05 may be appropriate for 0.4 and 0.8 mm thick disc based TLD badge. These (D_Open/D_Perspex) ratios are helpful in crude identification of the beta sources and to apply an appropriate correction factor for estimation of beta dose. The study may be helpful to improve beta dose estimation algorithms for personnel monitoring application in India.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.	Sherbini S, Sykes J 3^rd, Porter SW Jr., Lodde G. Experimental evaluation of a method for performing personnel beta dosimetry using multi-element thermoluminescent dosimeters. Health Phys 1985;49:55-64.
2.	Cross WG. Empirical expressions for beta ray point source dose distributions. Radiat Prot Dosimetry 1997;69:85-96.
3.	Pendurkar HK, Boulenger R, Ghoos L, Nicasi W, Mertens E. Proceedings 3^rd International Conference on Luminescence Dosimetry, Riso Report No. 249. (Riso: Danish AEC); 1971. p. 1089-6.
4.	Conteno G, Malisan MR, Padovani R. Response of thermoluminescence dosimeters to beta radiation and skin dose measurement. Phys Med Biol 1984;29:661-78.
5.	Lakshmanan AR, Chandra B, Pradhan AS, Kher RK, Bhatt RC. The development of thin CaSO₄: Dy Teflon TL dosimeters for beta dosimetry in personnel monitoring. Int J Appl Radiat Isot 1980;31:107-10.
6.	Vohra KG, Bhatt RC, Chandra B, Pradhan AS, Lakshmanan AR, Shastry SS. A personal dosimeter TLD badge based on CaSO4: Dy Teflon TLD discs. Health Phys 1980;38:193-7.
7.	Nagpal JS, Popli KL, Varadharajan G, Kher RK, Venkatraman G. Individual monitoring and its quality assurance using thermoluminescent CaSO₄: Dy Teflon tape dosimeters in India. Radiat Prot Dosimetry 1994;51:275-82.
8.	Nagpal JS, Varadharajan G, Jakheta AP, Venkatraman G. Selected studies with CaSO₄: Dy Teflon TL dosimeters for beta monitoring. J Med Phys 1996;21:146-8.
9.	Pradhan AS, Bhatt RC. Graphite-mixed CaSO₄: Dy teflon TLD discs for beta dosimetry. Phys Med Biol 1977;22:873-9.
10.	Mancosu P, Ripamonti D, Veronese I, Cantone MC, Giussani A, Tosi G. Angular dependence of the TL reading of thin alpha-Al2O3: C dosemeters exposed to different beta spectra. Radiat Prot Dosimetry 2005;113:359-65.
11.	Akselrod A, Akselrod MS, Agersnap Larsen N, Banerjee D, Bøtter-Jensen L, Christensen P, et al. Optically stimulated luminescence response of Al₂O₃ to beta radiation. Radiat Prot Dosimetry 1999;85:125-8.
12.	Pinto TN, Cecatti SG, Gronchi CC, Caldas LV. Application of the OSL technique for beta dosimetry. Radiat Meas 2008;43:332-4.
13.	Kumar M, Dhabekar B, Menon SN, Bakshi AK, Udhayakumar J, Chougaonkar MP, et al. Beta response of LiMgPO4:Tb, B based OSL discs for personnel monitoring applications. Radiat Prot Dosimetry 2013;155:410-7.
14.	Kulkarni MS, Ratna P, Kannan S. A new PC based semi-automatic TLD badge reader system for personnel monitoring. In: Proceedings of International Radiation Protection Association Conference, Hiroshima, Japan; 14-19 May, 2000.
15.	Kumar M, Alagu Raja E, Prasad LC, Popli KL, Kher RK, Bhatt BC. Studies on automatic hot gas reader used in the countrywide personnel monitoring programme. Radiat Prot Dosimetry 2005;113:366-73.
16.	Ambrosi P, Buchholz G, Helmstadter K. The PTB beta secondary standard BSS2 for radiation protection. J Instrum 2007;2:11002.
17.	Brunzendorf J. Depth-dose curves of the beta reference fields ¹⁴⁷ Pm,⁸⁵ Kr and ⁹⁰ Sr/⁹⁰ Y produced by the beta secondary standard BSS2. Radiat Prot Dosimetry 2012;151:211-7.
18.	Kumar M, Gupta A, Pradhan SM, Bakshi AK, Chougaonkar MP, Babu DA. Response of ionization chamber based pocket dosimeter to beta radiation. Appl Radiat Isot 2013;82:130-2.
19.	Dere AV, Popli KL, Nagpal JS, Kapoor DK, Patel PH. Dose computation algorithm for individual thermoluminescence dosimetry. Bull Radiat Prot 1993;16:54-5.
20.	Popli KL. Lecture Notes on Accreditation Programme for Nuclear Medicine Technologists in Radiation Safety. In: Gaur PK, editor. Radiological Physics and Advisory Division. Ch. 9. Mumbai: Radiological Physics and Advisory Division; 2000. p. 9.1.

Figures

[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

Tables

[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]

This article has been cited by
1	Estimation of Personal dose Equivalent Hp(0.07) Using CaSO4:Dy Teflon Disc-Based Extremity Dosemeter
	Madhumita Bhattacharya, Kasthuri Samuel, Sandeep Patil, Rohit Yadav, A K Bakshi, Sunil K Singh, B K Sapra
	Radiation Protection Dosimetry. 2022;
	[Pubmed] \| [DOI]

2	Investigation of TL characteristics of UV and gamma induced Eu3+ and Sm3+activated Y2O3 phosphors
	Tarkeshwari Verma,Sadhana Agrawal
	Chemical Physics Letters. 2020; 743: 137158
	[Pubmed] \| [DOI]

3	Further considerations on “Towards the origins of over-dispersion in beta source calibration” by Hansen et al., radiation measurements, 2018
	Munish Kumar
	Radiation Measurements. 2019; 126: 106137
	[Pubmed] \| [DOI]

4	SOL-GEL a-Al2O3 detectors: TL and OSL response to beta radiation beams
	Ivón Oramas Polo,Linda V.E. Caldas
	Radiation Physics and Chemistry. 2019;
	[Pubmed] \| [DOI]

5	BETA DOSE EVALUATION ALGORITHM FOR CaSO4:Dy BYSED TLD BADGE USED IN COUNTRYWIDE PERSONNEL MONITORING PROGRAMME IN INDIA
	R. B. Rakesh,Munish Kumar,C. Sneha,P. Ratna,D. Datta
	Radiation Protection Dosimetry. 2016;
	[Pubmed] \| [DOI]