Assessment of neutron dose in Indus accelerator complex using CR-39 SSNTD

Indus accelerator complex (IAC) consists of two synchrotron radiation sources namely Indus-1 and Indus-2. The radiation environment here is mainly due to bremsstrahlung and photo-neutrons. Major problems faced in neutron detection in IAC are the severely pulsed nature and gamma (bremsstrahlung) interference. Thus, to assess the neutron dose rates in the accessible and inaccessible areas of IAC, passive integrating type neutron detectors CR-39 and bubble detectors are used. The dose rates observed at microtron body; booster injection and extraction septum are significant (few mSv/h) when compared to other locations in IAC. From bubble detector data, it can be seen that the dose rate during injection is high (maximum 112 μSv/h) compared with storage mode (maximum 2.6 μSv/h) indicating high beam loss during injection. During the injection, the personnel are not allowed in these areas due to high radiation doses on account of the beam loss. The neutron dose rates observed for accessible areas are three orders of magnitude less than the inaccessible areas in the complex.