Nuclear Physics Home

An array of twenty four HPGe Clover detectors for nuclear structure studies

Electronics and Data Acquisition System

NIM and CAMAC Modules Developed In-house

INGA Clover modules

HV power supplies for Clovers

HV power supplies for ACSs

Home-made Clover modules are used for processing the energy signals from Clover detectors and anti-Compton shields. The timing logic for Compton-suppression along with the generation of required strobes for data collection and pile-up rejection were also incorporated in this module. The gain setting of the shaping amplifiers of Clover segments are kept at 4 MeV range. One NIM bin is used for powering four Clover modules. Eight detectors are grouped into one unit for creating multiplicity of γ-rays and for collecting data through one CAMAC crate. The combined multiplicity from all three crates is used for event selection.

New home-made LPCC CAMAC modules have been fabricated combining the List Processor (LP) and the Crate Controller (CC) which enables the data collection rates up to 1700 kilo bytes per second. Three CAMAC crates each having four 14 bit, 8 channel home-made AD814 ADCs, are used to collect data from all Compton-suppressed Clover detectors. The first CAMAC crate has the trigger generator which entertains the event trigger and transmits it to the other two CAMAC crates via trigger receiver modules of respective crates to maintain the synchronization of data between the three crates. The TDCss (PHILLIPS 7186) are used to create the hardware bit pattern in each CAMAC crate. The hardware bit pattern based data collection (CNAF list changes as per the bits raised for each event in TDC's of each crate) is also enabled to have more data collection due to zero suppression in data readout. The data collection software CANDLE is run in a dedicated PC with local data archival system. All the bias supplies, analogue processing modules and analogue to digital converters (except TDCs) have been fabricated in-house.

Analog to digital converters

INGA data room

INGA array

Trigger Logic

INGA electronics block diagram

INGA master gate

Data Rates

Multiplicity distribution

For multi-crate readout of ∼ 120 parameters, hardware supression is enabled, based on the hardware bit pattern readout of TDC. In the triples (γ-γ-γ) mode, on average the dead time is about 45 μs. Typical coincidence count rates were ∼ 12 kcs (γ-γ) doubles and 3-4 kcs (γ-γ-γ) triples for a total singles (γ) rate of 60-80 kcs. An oscilloscope trace of the multiplicity distribution is shown in the left figure.

Contact us:
S. Muralithar
Inter University Accelerator Centre
Aruna Asaf Ali Marg, Post Box 10502
New Delhi 110067, India
Phone: +91 11 26893955
Telefax: +91 11 26893666
This page is maintained by S. Muralithar ( ). Last updated on January 23, 2012.