Construction and alignment experience of Indus-1 SRS in C.A.T

A 450 MeV Synchrotron Radiation Source, Indus-1 is being constructed at Centre for Advanced Technology at Indore in central India. This paper narrates our experience in construction and alignment of synchrotron machines which was first of its kind for most of us. Careful design, planning and execution of the work yielded modest results so that alignment accuracies between 0.1 to 0.3 mm could be achieved (in booster synchrotron) and, which have proved to be adequate up till now. The building of the SRS complex was constructed such that machine rings have their foundations isolated from rest of the building. A number of 100 x 150 mm size steel plates were embedded in the concrete of floor and walls to serve as base for reference surveying marks which were established later. The pre-injector and booster ring are enclosed in a radiation shielding zone with separate ventilation system. Dipoles, quadrupoles and a few sextupoles were fiducialised during their field mappings; on a CNC Hall-probe manipulator for dipoles and on rotating coil measuring machine for others. Fiducials were of two types- sticker type as well as accurately reamed holes to receive a precision target for alignment measurements with optical instruments. Due to small size of entire machine zone, we decided and used precision surveying method of using ECDS-2 coordinate determination system of KERN (now, Leica) and micrometer type N3 level of WILD. Additionally, accurate spirit levels (10/20 micron per m.) for preliminary leveling and an interferometer to calibrate CNC Hall-probe manipulator were also used. We faced some problems due to instrument failures which were circumvented by mixed use of KERN and WILD theodolites and hand feeding angular readings in the ECDS-2. Of late, the booster synchrotron experiments have established acceleration up to 480 MeV albeit, with very weak current, about 2 mA and first synchrotron light emission was directly observed on 26th Sept. 1995. (J.P.N.)