PN3-GAMS - High resolution gamma-ray facility PN3-GAMS
PN3 - Gamma-Ray Spectrometers GAMS4 and GAMS5
The high resolution gamma ray facility GAMS makes use of the fact that, at the ILL reactor, one can obtain extremely high specific activities when exploiting thermal neutron capture at an in-pile target facility. This allows us to aim for the application of gamma spectroscopy with the highest possible energy resolution. Many studies on this facility have aimed to contribute to our understanding of the structure of nuclei. Others are devoted to the determination of standards and fundamental constants or to deduce information about short lifetimes of excited nuclear states.
Applications
Spectroscopy: classical "complete" spectroscopy of the decay of excited nuclear states
Lifetimes: measurement of lifetimes of excited nuclear states (by gamma-ray induced Doppler broadening - GRID)
Standards: measurement of fundamental constants ; measurement of standards for x-rays and gamma-rays
Crystal Difraction: detailed studies of crystal diffraction processes
Inter-atomic Potentials: study of slowing down processes of atoms recoiling in matter
Instrument layout
PN3 is in fact a set of two gamma-ray spectrometers GAMS4 and GAMS 5 installed on both ends of the neutron tube H6-H7.
A general view of the instrument
The challenge faced by the GAMS spectrometers is managing to measure angles with a precision of less than one millionth of a degree (the angle of view of an apple seen from a distance of 100 km). In fact, the wavelength of gamma rays is exceptionally short and they are little deviated by matter.
GAMS are double monocrystal spectrometers. The photo shows the Laser interferometer measuring the rotation angle of these crystals which analyze incident gamma rays.
