Atomic Physics

General Purpose Atomic Physics Chamber (GPAC)

GPAC is a stainless steel vessel installed at 30^oin one beam line of light ion beam room (LIBR) at NSC. The height of the chamber is 316 mm and its internal diameter is 356 mm. The chamber mounted on rigid raw steel support was designed to carry out atomic physics experiments. With the commissioning of the LINAC at IUAC the chamber is going to be dismantled from LIBR and reistalled in Beam hall-II. The essential features of the chamber include :

Computer controlled movable foil setup mounted on the horizontal rail that can be used for standard time of flight experiments.
An arrangement for holding multiple foils in a ladder is made. Any one of which can be brought in the beam line during the experiment using a remote control setup from the Data-Room. The facility is used for studying the interaction of the excited states with thin foils.
Triple axis target manipulator capable of holding as many as 30 targets for inner shell ionization cross-section measurements.
Two ray detectors can be simultaneously mounted at right angles to the beam axis to observe the decay of excited states in the post-foil beam.
The chamber has an exit port for the post foil beam which facilitates further study of the post-foil beam by using electrstatic analyzer and position sensitive detector for post foil charge state analysis.
The base and the top flange of the the chamber has M6 tapped holes at 15 degrees so as to mount different experimental accessories like mounting arrangement for SSBD detectors, railway track for Time of flight experiments etc.
An option to study the interaction of beam with gas jet or gas-cell has also been incorporated in the chamber the the facility is planned to be explored in the near future.
The chamber has the an option to manually bring a 3 cm diameter quartz in the beam line for beam tuning. The quartz once in the beam line can be viewed through a 40 CF view port at 30^o to the beam axis.
To reduce the SSBD noise level a special 40 CF feed through flange have been fabricated and installed which isolates the output lines from the chamber, it has been observed the noise pickup level is drastically reduced to less 5 mV.
Chamber has been coupled with a dedicated 250l/s turbo-molecular pump to achieve 10^-7 mbar vacuum within two hours time