Electron beam loss in an electron accelerator leads to production of intense bremmstrahlung photons. Some of the photons interact with nuclei of surrounding material to produce residual induced activity by photonuclear reactions. These facts were effectively used by Health Physics Unit to determine the locations and magnitude of electron beam loss in 20 MeV Microtron and 450 MeV Booster Synchrotron in Indus-1 Complex at RRCAT, Indore. Three methods were employed for beam loss detection viz. (i) on line radiation monitoring using area monitors (ii) integrated dose measurement using pocket dosimeters and chemical dosimeters (off line) and (iii) induced activity measurement using radiation survey meter (off line). These techniques were occasionally used by Beam Physicists to solve the problems related with beam loss detection and efficient operation of the accelerators when needed. The experimental study has proved .the effectiveness of conventional radiation detectors in beam loss detection in electron accelerators. There is plan to use on line signal from PIN Diodes as beam 10$s detectors developed by Electronics Division, BARC
From the results of the beam loss detection experiments, we were able to conclude that significant beam loss takes place in the direction of circulating electron beam within the RF cavity in Injector Microtron. At booster synchrotron, high beam loss was observed near the injection septum during normal operation, Beam loss location, a bellow in Transfer Line of 12 MeV Radiotherapy Machine was determined using this technique. Replacing a bellow with bigger inner aperture improved exit current at treatment head from 10 mA to 20 mA.