1. bookVolume 59 (2014): Issue 3 (August 2014)
Journal Details
License
Format
Journal
eISSN
1508-5791
First Published
25 Mar 2014
Publication timeframe
4 times per year
Languages
English
access type Open Access

Occupational exposure to Am-Be neutron calibration source mounted in OB26 shielding container

Published Online: 12 Sep 2014
Volume & Issue: Volume 59 (2014) - Issue 3 (August 2014)
Page range: 97 - 103
Received: 11 Feb 2014
Accepted: 21 Jul 2014
Journal Details
License
Format
Journal
eISSN
1508-5791
First Published
25 Mar 2014
Publication timeframe
4 times per year
Languages
English
Abstract

Laboratory for Dosimetric and Radon Instruments Calibration which is a part of Central Laboratory for Radiological Protection (CLRP) in Warsaw is equipped with 241Am-Be neutron calibration source with activity of 185 GBq since 1999. The capsule was mounted in the OB26 type shielding container. The control room is separated from the above source by a concrete wall of 0.5 m in thickness. The calibration hall is adjacent to one side of the offi ce room. To comply with the requirements of the radiological protection system, the occupational exposure of persons that are working both in the offi ce and control room needs to be assessed. Two methods were involved for ambient dose equivalent rate determination. The active instrument measurements (AIMs) performed with the Berthold LB6411 neutron probe and the Monte Carlo simulation method (MCS) based on MCNP5 code. These estimations were completed for fi ve reference points. Additionally the γ radiation component was measured by RSS131 ionisation chamber. An increased value of the ambient dose equivalent rate from neutrons was observed in two reference positions. The fi rst observation was done in the control room while the second one in the offi ce room. Expected individual dose equivalents were evaluated based on the results of the AIM and on the expected working time in particular reference points. The annual individual dose equivalent associated with calibration activities using mentioned neutron source was estimated at maximum 0.8 mSv.

Keywords

1. International Organization for Standardization. (2001). Reference neutron radiations, part 1: Characteristics and methods of production. Geneva, Switzerland. (ISO 8529-1).Search in Google Scholar

2. Jozefowicz, K., Golnik, N., & Zielczynski, M. (2004). Standard fi elds of old neutron sources - parameters and traceability. Radiat. Prot. Dosim., 110(1/4), 107-110.10.1093/rpd/nch19415353631Search in Google Scholar

3. Jozefowicz, K., Golnik, N., Tulik, P., & Zielczynski, M. (2007). Radionuclide neutron sources in calibration laboratory - neutron and gamma doses and their changes in time. Radiat. Prot. Dosim., 126(1/4), 134-137.10.1093/rpd/ncm02917513855Search in Google Scholar

4. Schuhmacher, H. (2004). Neutron calibration facilities. Radiat. Prot. Dosim., 110(1/4), 33-42.10.1093/rpd/nch21515353618Search in Google Scholar

5. Mazrou, H., Sidahmed, T., & Allab, M. (2010). Monte Carlo investigation of radiation beam quality of the CRNA neutron irradiator for calibration purposes. Appl. Radiat. Isot., 68(10), 1915-1921.10.1016/j.apradiso.2010.04.02220471278Search in Google Scholar

6. X-5 Monte Carlo Team. (2003). MCNP - A General Monte Carlo N-Particle Transport Code. Version 5. Volume I: Overview and theory. Los Alamos: Los Alamos National Laboratory.Search in Google Scholar

7. Mazrou, H., Sidahmed, T., & Allab, M. (2010). Neutron fi eld characterisation of the ob26 crna irradiator in view of its use for calibration purposes. Radiat. Prot. Dosim., 141(2), 114-126.10.1093/rpd/ncq16620554579Search in Google Scholar

8. McConn Jr, R. J., Gesh, C. J., Pagh, R. T., Rucker, R. A., & Williams III, R. G. (2011). Compendium of material composition data for radiation transport modeling - radiation portal monitor project. Washington: Pacifi c Northwest National Laboratory Richland.Search in Google Scholar

9. Berthold Technologies. (1996). Neutron probe LB6411 - operating manual. Bad Wildbag, Germany.Search in Google Scholar

10. Blizard, E. P., & Miller, J. M. (1958). Radiation attenuation characteristics of structural concrete. Oak Ridge: Oak Ridge National Laboratory. (ORNL-2193).10.2172/4300525Search in Google Scholar

11. Murata, I., Tsuda, I., Nakamura, R., Nakayama, S., Matsumoto, M., & Miyamaru, H. (2014). Neutron and gamma-ray source-term characterization of AmBe sources in Osaka University. Progress in Nuclear Science and Technology, 4, 345-348. 10.15669/pnst.4.345Search in Google Scholar

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