Identification and Angular Distribution of Residual Radionuclides Detected on the Wall of BATAN’s Cyclotron Cave

Abstract

Detection and measurement of radiation sources around BATAN's cyclotron facilities in Serpong are required as an early step to avoid radiation impacts on the radiation employees who work with the cyclotron. In this paper, radiation emitted from the wall of the CS-30 cyclotron cave are detected and measured using an NaI(Tl) detector coupled with a pocket multichannel analyzer (MCA) at a counting time of 30 minutes for each sampling point on the wall. The sampling points were in the directions of within ±150 o with respect to the incoming proton beams, and the measurements were conducted at heights between 1.2 m and 1.8 m off the floor for every sampling point. The experimental results indicate that Co-60 and Cs-134 detected on the cyclotron cave wall are major radionuclides that contribute to the emitted gamma radiation. The distribution of the gamma ray intensities given off by Co-60 and Cs-134 depend on the angle and position of the sampling points. In general the highest gamma ray rates can be found in the area around 0 o relative to the incoming proton beams. In addition, no other radioactive sources are significantly detected on the wall. The maximum exposure measured on the wall surface was much less than the permissible occupational exposure for radiation workers and general public.

Dependence of 18F Production Yield and Radioactive Impurities on Proton Irradiation Dose

“…While the Havar window used in this investigation is perpendicularly hit by the incoming proton beam, the silver body is parallel to the beam as discussed in previous studies [14]. Secondary neutrons generated by the (p,n) reactions are most likely to hit any materials perpendicular to the incoming proton beam as highlighted in earlier similar investigation [17]. As a result, it makes the Table 3, at the end of bombardment (EOB), the average ratio between each impurity and 18 F yield ranges between 1.2 and 6.2%.…”

“…A portable gamma ray spectroscopy system which has been described elsewhere [14,17] was used to detect and quantify the radionuclidic impurities. The Amptek-USA made spectrometer included a pocket MCA (Type MCA8000A) with the serial number 2278.…”

Spectral Analysis of Proton-Irradiated Natural MoO3 Relevant for Technetium-99m Radionuclide Production

“…The radioactivities of the solid MoO 3 as well as the NaOH-dissolved MoO 3 target were measured using a portable gamma ray spectroscopy system, which had been described elsewhere [12][13]. The measurement was performed by sampling 10 µL of the NaOH-dissolved MoO 3 solution for a counting time of 5 minutes for each sample, and each spectrum was analyzed after background subtraction.…”

Residual Radioisotopes Generated from Neutron Irradiated Aluminum Capsules

“…A portable gamma ray spectroscopy system consisting of a pocket MCA (Type MCA8000A) made by Amptek, USA with the serial number 2278 coupled to a NaI(Tl) detector was employed to identify the radioactive by-products present in the Al capsules. The energy calibration of the spectroscopy system was performed using 137 Cs, 60 Co and 241 Am standard radioactive sources as discussed elsewhere (Kambali et al 2016;Kambali & Suryanto 2016a;Kambali & Suryanto 2016b). The background-subtracted gamma ray spectrum of the Al capsules was then analyzed for samples irradiated using the G.A Siwabessy nuclear reactor and the 11-MeV cyclotron.…”