Dose assessment on temperature monitoring units in Indus-2 tunnel

Temperature Monitoring Units (TMUs) are installed in Indus-2 storage ring tunnel to measure the temperature on dipole vacuum chamber. Erroneous reading from the TMUs was reported and suspected that radiation damage may be causing the malfunctioning. In order to ascertain the malfunctioning due to radiation damage, a dose assessment on the TMU and nearby locations were performed using CaSO₄: Dy thermo-luminescence (TL) discs. Before the measurement, TL discs were annealed and exposed to ⁶⁰Co radiation for known dose and discs within ±10% were selected for the measurement. The measurement was carried out for 10 days at the TMU locations and surrounding areas which covered total of 12 locations. The results indicate that radiation damage is probable cause of malfunctioning as the projected dose over an year, based on the measurement, is found to cross the damage threshold. The paper describes the details of the measurement and results. (author)