Welcome to Physics Group
Variable Energy Cyclotron Centre, Kolkata

Large, Segmented, Horizontal Axis, Reaction Chamber (SHARC) ...

This large, segmented, horizontal axis, reaction chamber (SHARC) is integrated with the beam line in the VECC superconducting cyclotron (SCC) experimental area. It is a cylindrical, three segment, stainless steel chamber  of length 2.2 m, diameter 1 m and wall thickness ~10 mm; the front  (beam-entry) end is hemispherical in shape having a radius  500 mm and the rear end is elliptical dish (2:1) shaped. Inside SHARC, there are two pairs of parallel rails to put a target ladder and a generalized detector mounting table. The whole target assembly can be placed anywhere on the rail with vertical and rotational movement facility controllable remotely. The generalized detector mounting table has precision alignment mechanism on manually movable stands with a locking arrangement. There is no rotating arm inside; users are encouraged to fabricate their own detector stands as per requirement. The  vacuum   (in  empty  chamber)  ~1X10^-7  mbar is obtained in 10 hrs by means of two turbo molecular (1000 litre/sec) and two cryo pumps (2500 litre/sec) backed by  mechanical pumps.  

Neutron Multiplicity Detector

Nutron Multiplicity Detector constitutes a powerful means for the nuclear temperature measurements. It allows to measure, event by event, with high efficiency, the number and total kinetic energy of neutrons emitted in a nuclear reaction. This detector has been developed first time in our country. NMD consists of two stainless steel hemispheres of one metre diameter, filled with 500 litres of 0.5% Gd loaded liquid scintillator BC521. This development involved many sophisticated subsystem developments like, pumping system for liquid scintillator, scintillator testing setup and readout electronic, etc. One of the important characteristics of the above detector is the capture time distribution, which depends on the quantity of the Gd doped in the liquid sctillator.

Neutron Detectors for Time of Flight Measurement

To boost up the experimental nuclear physics research in the country, several detector arrays were planed at VECC under the super conducting cyclotron utilisation project, neutron Time OF Flight (TOF) array is among one of major system. Neutron TOF array has been developed for the precise measurement of neutron energy and angular distribution. The array consists of 50 numbers of neutron detectors, each having 5" diameter and a similar length. Detectors are liquid scintillator based and have been indigenously designed and developed at VECC, after long, involved and careful R & D effort. The primary motivation of the array is to look for answer of the some of today's frontline nuclear physics problems, understand the fission dynamics at near barrier energies, measurement of nuclear level density parameter, multi-fragmentation, exotic fragment studies, etc.

Large Area Modular BaF2 Detector Array (LAMBDA)

It is a high energy photon spectrometer, complete with its dedicated front end electronics & data acquisition system.

Gas detector developement

At VECC, we have an active research program to develop gas detectors for detection of heavy charged particles. After an intensive R and D efforts, few position sensitive Multi-Wire Proportional Counters (MWPC) were designed and fabricated indigenously. These large area detectors (typical area is 20 cm x 6 cm) are proficiently used in experiments at the major accelerator facilities available in our country. The position resolution achieved with these detectors is better than a millimetre and time resolution better than a nanosecond. We have also developed avalanche counters (5 cm x 3 cm active area) that is efficient for ”start time“ measurement in a time of flight setup.

GAMma Multiplicity filter Array (GAMMA)

This array is for the measuring angular momentum of high energy photonevent-by-event.

Penning Trap Developement

Penning trap is a device to store charged ions and sub-atomic particles using a strong homogeneous magnetic field and a weak inhomogeneous electrostatic field. The mass of the trapped charged particle can be determined very accurately by measuring the axial and cyclotron frequencies of the trapped ion. At VECC, we are building a cryogenic Penning trap facility where the trap would be at liquid helium (4 K) temperature and plan to put in radioactive ions in it. In addition to the mass measurements, our emphasis would be on the measurement of the kinetic energies of the recoiled daughter nuclei from the beta decay processes to measure accurately Q-values of the reaction and also try to determine the mass of an electron-neutrino from the end-point of the beta decay spectrum.

High-energy photon spectrometer

Electromagnetic radiation produced in nuclear reactions has been an important subject of study since the beginning of nuclear science. Since, the electromagnetic radiation is not seriously affected by the nuclear medium, it is the most suitable probe of choice to the study the properties of nuclear systems. In order to measure the high-energy gamma rays from hot nuclear systems, the following two detector systems (LAMBDA & GAMMA) have been developed in-house and are currently being used.

Charged Particle Detector Array (CPDA)

A 4pi-charged particle detector array is being developed at VECC. The array will consist of three parts: (a) the forward array covering 7 to 45 degree with silicon-silicon-CsI(Tl) telescopes, (b) extreme forward array covering 3 to 7 degree with phoswich detectors  and (c) the backward array covering 45 to 175 degree with 330 CsI(Tl) crystals.