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Portocarrero Bonifaz A, Bosch Moliné O, Olivares Schneider J, La Rosa La Rosa B, Rojas Hancco J, Guevara Rojas V, Palacios Fernández D, Pereyra Anaya P, López Herrera ME. Simple and low cost alternative method for detecting photoneutrons produced in some radiotherapy treatments using SSNTDs. Appl Radiat Isot 2020; 161:109169. [PMID: 32321701 DOI: 10.1016/j.apradiso.2020.109169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/07/2020] [Accepted: 03/28/2020] [Indexed: 10/24/2022]
Abstract
A simple and low cost alternative which is able to identify thermal and fast neutrons in a clinical environment of radiotherapy is presented. CR-39 and LR-115 Solid State Nuclear Track Detectors (SSNTDs) were used, estimating their viability. In order to register alpha tracks due to thermal neutrons, natural boric acid tablets were placed in close contact to the detector, whereas in order to detect epithermal neutrons, some were additionally covered in a thin cadmium layer. Different configurations were assembled, changing the position of the converter with respect to the detector and the incident neutron fluence, which was evaluated in different positions of a radiotherapy table. The contribution due to environmental 222Rn and its daughters to the track density registered by the detector during the measurements was found to be negligible. It is concluded that the designed experimental set up constitutes a trustworthy and affordable method to carry out neutron measurements with the recommended configurations provided for the CR-39 detector, and not with LR-115.
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Affiliation(s)
| | - Oriol Bosch Moliné
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Jose Olivares Schneider
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Brian La Rosa La Rosa
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Jhonny Rojas Hancco
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Vanessa Guevara Rojas
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | | | - Patrizia Pereyra Anaya
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
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Novel poly (sulfone-carbonate) polymers for rapid revelation of charged particle tracks by chemical etching process. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Influence of external and internal conditions of detector sample treatment on the particle registration sensitivity of Solid State Nuclear Track Detectors of type CR-39. RADIAT MEAS 2012. [DOI: 10.1016/j.radmeas.2012.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bulk etch rate estimation of LR-115 SSNTD using PHOENIX interface. RADIAT MEAS 2011. [DOI: 10.1016/j.radmeas.2011.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Choi VWY, Ng CKM, Lam RKK, Janik M, Sorimachi A, Kranrod C, Nikezic D, Tokonami S, Yu KN. Long-term determination of airborne radon progeny concentrations using LR 115 detectors and the effects of thoron. RADIATION PROTECTION DOSIMETRY 2010; 141:404-407. [PMID: 20833677 DOI: 10.1093/rpd/ncq255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The 'proxy equilibrium factor' (F(p)) method has been developed for long-term determination of airborne radon progeny concentrations using LR 115 solid-state nuclear track detectors. In this paper, the effects of (220)Rn on the F(p) method have been studied. The correction to the track density was related to a parameter α which was the ratio of the sum of activity concentrations of alpha-particle emitting radionuclides in the (220)Rn decay chain to the activity concentration of (220)Rn alone. Under commonly encountered circumstances, α could not be smaller than 2. An attempt was made to verify this using the exposure chamber at the National Institute of Radiological Sciences (NIRS), Chiba, Japan. A most interesting observation of α < 2 for very high (220)Rn concentrations and very low equilibrium factors for (220)Rn in the exposure chambers was made. A possible explanation was the substantial deposition of (216)Po under the extreme conditions inside the exposure chambers.
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Affiliation(s)
- V W Y Choi
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong
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Mireles F, Dávila JI, García ML, Pinedo JL, López H. Evaluation of efficiency calibration parameters of the LR-115 radon detector. HEALTH PHYSICS 2010; 98 Suppl 2:S63-S68. [PMID: 20386194 DOI: 10.1097/hp.0b013e3181d27376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Measurement of 222Rn is an important research concern because of the high-energy alpha emission of its 218Po and 214Po progeny. The LR-115 passive detector is the basis of a solid-state nuclear track detector (SSNTD) whose use for radon measurements has been well established. The usage of the SSNTD technique requires calibration by comparison. The aim of this work is to evaluate the efficiency calibration parameters for the radon measurement system that three steps: (1) irradiation conditions, (2) etching conditions, and (3) track counting. The following parameters were evaluated: breakdown and counting voltages for the spark counter, detector thickness, etching time, temperature and NaOH concentration as etching conditions for the LR-115 detector. Calibrating factors of 0.035 and 0.028 tracks cm-2 Bq-1 m3 d-1 for the open- and closed-chamber radon monitors, respectively, were determined considering the best efficiency calibration parameter values.
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Affiliation(s)
- F Mireles
- Unidad Académica de Estudios Nucleares, Universidad Autónoma de Zacatecas, Ciprés 10, Frac La Peñuela, Zacatecas, Zac., CP 98068, Mexico
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Yip C, Nikezic D, Yu K. Retrospective radon progeny measurements for dwellings based on implanted activities in glass objects. RADIAT MEAS 2008. [DOI: 10.1016/j.radmeas.2008.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ditlov V, Awad E, Hermsdorf D, Fromm M. Interpretation of the bulk etching process in LR-115 detectors by the many-hit model. RADIAT MEAS 2008. [DOI: 10.1016/j.radmeas.2008.03.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Leung SYY, Nikezic D, Leung JKC, Yu KN. Derivation of V function for LR 115 SSNTD from its sensitivity to 220Rn in a diffusion chamber. Appl Radiat Isot 2007; 65:313-7. [PMID: 17029818 DOI: 10.1016/j.apradiso.2006.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 07/12/2006] [Accepted: 08/10/2006] [Indexed: 10/24/2022]
Abstract
The sensitivity of the LR 115 detector inside a diffusion chamber to (220)Rn gas concentration is dependent on the removed active layer thickness during chemical etching. This dependence is related to the V function for the LR 115 detector (where V is the ratio between the track etch velocity V(t) and the bulk etch velocity V(b)) and the geometry of the diffusion chamber. The present paper presents the experimentally determined relationship between the sensitivity of the LR 115 detector inside a Karlsruhe diffusion chamber (determined from the number of etched tracks completely penetrating the active cellulose nitrate layer) and the removed active layer thickness. These data were used to derive the V function for the LR 115 detector, which took the functional form of the Durrani-Green's function, i.e., V=1+((a1e-)(a2R+a3e(-a)4R))(1(-e)(-a5R)), with the best-fitted constants as a(1)=14.50, a(2)=0.50, a(3)=3.9 and a(4)=0.066.
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Affiliation(s)
- S Y Y Leung
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong
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Leung SYY, Nikezic D, Yu KN. Derivation of V function for LR 115 SSNTD from its partial sensitivity to 222Rn and its short-lived progeny. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2007; 92:55-61. [PMID: 17088014 DOI: 10.1016/j.jenvrad.2006.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 09/09/2006] [Accepted: 09/19/2006] [Indexed: 05/12/2023]
Abstract
Solid-state nuclear track detectors (SSNTDs) have been widely applied for measurements of environmental concentrations of 222Rn and its progeny. The V function for an SSNTD is important for understanding the track development in the SSNTD as well as for real life applications. The partial sensitivity rhoi of the LR 115 detector applied in the bare mode to 222Rn and its short-lived progeny is related to the equilibrium factor F through the proxy equilibrium factor Fp. On the other hand, rhoi is also dependent on the removed active layer thickness during chemical etching, which is related to the V function for the LR 115 detector. In the present paper, the experimentally obtained rhoi values of the LR 115 detector for different removed active layer thickness are used to derive the V function for the LR 115 SSNTD, which took the form of the Durrani--Green's function, i.e., [formula: see text] , with the best-fitted constants as a1=14.23; a2=0.48; a3=5.9 and a4=0.077 (a5=1).
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Affiliation(s)
- S Y Y Leung
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong
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Nikezic D, Ng FMF, Yu KN. Theoretical basis for long-term measurements of equilibrium factors using LR 115 detectors. Appl Radiat Isot 2004; 61:1431-5. [PMID: 15388144 DOI: 10.1016/j.apradiso.2004.05.065] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2004] [Revised: 04/18/2004] [Accepted: 05/04/2004] [Indexed: 11/19/2022]
Abstract
In this paper, we propose a method to determine the equilibrium factor using a bare LR 115 detector. The partial sensitivities rhoi of the LR 115 detector to 222Rn and its alpha-emitting short-lived progeny, 218Po and 214Po, were investigated. We first determined the distributions of lengths of major and minor axes of the perforated alpha tracks in the LR 115 detector produced by 222Rn, 218Po and 214Po through Monte Carlo simulations. The track parameters were calculated using a track development model with a published V function, by assuming a removed active layer of 6.54 microm. The distributions determined for different alpha emitters were found to completely overlap with one another. This implied equality of partial sensitivities for radon and its progeny, which was also confirmed through analytical considerations. Equality of partial sensitivities makes possible convenient measurements of the proxy equilibrium factor Fp, which is defined in the present work as (F1+F3) and is equal to the ratio between the sum of concentrations of the two alpha emitting radon progeny (218Po+214Po) to the concentration of radon gas (222Rn). In particular, we have found Fp = (rho/rhoitC0)-1, where rho (track/m2) is the total track density on the detector, rhoi = 0.288 x 10(-2) m, t is the exposure time and C0 (Bq/m3) is the concentration of 222Rn. If C0 is known (e.g. from a separate measurement), we can obtain Fp. The proxy equilibrium factor Fp is also found to be well correlated with the equilibrium factor between radon gas and its progeny through the Jacobi room model. This leads to a novel method for long-term determination of the equilibrium factor.
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Affiliation(s)
- D Nikezic
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong
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Yip C, Ho J, Nikezic D, Yu K. A fast method to measure the thickness of removed layer from etching of SSNTD based on EDXRF. RADIAT MEAS 2003. [DOI: 10.1016/s1350-4487(03)00115-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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