Performance of Indian National Gamma
Detector Array
(INGA) Coupled with a Fast Digital Data Acquisition System for
Nuclear Struture
Studies, R. Palit.
S. Saha, J.
Sethi, T. Trivedi, B. S. Naidu, P.B. Chavan, R. Donthi, S. Jadhav
for INGA
collaboration, Tata
Institute of
Fundamental Research, Mumbai-400005, INDIA − Discrete gamma
ray
spectroscopy using large array of Compton suppressed high purity
germanium
detectors continues to provide new insights on the structure and
dynamics of
the nuclear systems. The Indian National Gamma Detector
Array(INGA) is set up
at TIFR-BARC accelerator facility at Mumbai, as a part of a
collaboration
between BARC, IUAC, SINP, TIFR, UGC-CSR-KC, VECC and different
Universities.
The array is designed for 24 Compton suppressed clover detectors
providing
around 5% photopeak efficiency. INGA along with other ancillary
detectors using
analogue electronics and CAMAC based data acquisition system has
been used for
the investigation of variety of nuclear structure phenomena, e.g.,
shape
coexistence, magnetic/anti-magnetic rotation, chiral rotations,
coupling of
gamma vibration with other modes, high spin states of neutron rich
nuclei in
sd-shell, and isomers near shell closure. Recently, a digital data
acquisition
system with 96 channels (based on Pixie-16 modules developed by
XIA LLC) has
been implemented for this Compton suppressed clover array. The
system has been
tested with 64 channels with the event rate up to 125 kHz with
2-fold
coincidence rate among any two crystals.The timing properties of fast scintillator detectors with
the existing
DDAQ have been investigated. This facilitates the lifetime
measurements of
isomeric states from 1 nsec to few microsec during the usual
gamma-gamma
coincidence measurement. Conventional systems with analog shaping
has being
replaced by digital system that provides higher throughput, better
energy
resolution and better stability for the multi-detector Compton
suppressed
clover array. The results from the initial in-beam experiments of
the complete
set-up and scope for the future nuclear structure and reaction
measurements
will be presented.