About INGA

The concept of a national facility for γ-spectroscopy took shape in early 2000 when a formal agreement between the various institutions (TIFR, BARC, SINP, VECC, UGC-DAE CSR and IUAC) was achieved for pooling the available resources. It was conceived that an Indian National Gamma Array consisting of Compton-suppressed Clover detectors with nearly 4π coverage would be set up as a national facility.

This facility would be rotated among the three accelerator laboratories in India with a minimum stay of one year at one place. Major funding for this project has been received from the Department of Science and Technology, Government of India. The Clover detectors that were available with the institutions were designed to be operated at a distance of ∼ 24 cm from the target with the accompanying anti-Compton shields subtending an angle of 30^o at the target. As a result, a maximum of 24 Clover detectors could be accommodated in 4π geometry. The total coverage by Ge crystals is about 25% of 4π, corresponding to a total photopeak efficiency of ∼ 5%. Such a system would be optimized for collecting data at triples (γ-γ-γ) or at higher fold. Three campaigns with a smaller number of Clover detectors were carried out in 2001, 2003 and 2005 at TIFR, IUAC and VECC, respectively, with existing infrastructure.

Fabrication of the mechanical support structure at IUAC for holding 24 Clover detectors was taken up in early 2007 and completed by mid-2007. It was decided that the first campaign with the full INGA during 2007-2008 would take place at IUAC. Installation of the mechanical structure, cabling and electronic modules started by August 2007. The detectors and shields from all the collaborating institutions were received by January 2008. The first facility test to optimize the transport of beam at INGA beam line was carried out in February 2008. During March to June, 2008, the first cycle of experiments with the INGA facility was carried out.