07 Jun 2011



ECLAN - Experimental Chamber with Low Attenuation for Neutrons




The Experimental Chamber with Low Attenuation for Neutrons (ECLAN) is a general purpose scattering chamber.

The chamber was designed and constructed by the NPG for use at the SPIRAL (link opens in a new window) facility at GANIL (link opens in a new window) in Caen, France. The chamber is of 1m diameter, with four remotely controlled, rotatable arms on which beam tracking detectors (drift chambers / PPACs etc.) and charged particle detector arrays (gas ionization chambers / Si position sensitive detectors / CsI scintillators) may be mounted. A remote control linear target drive mechanism will also be incorporated.

The design of the chamber is optimised for the study of light neutron rich nuclei which will be performed at GANIL/SPIRAL, where the detection of neutrons is important. The walls of the chamber are made of thin aluminium alloy (~4mm), with no protruding ports or vacuum flanges in the forward hemisphere. A thin domed lid will enable additional detectors to be placed above the chamber and also contains a large port for TV cameras or recessed gamma-ray detectors which subtend a large solid angle at the target position.

The chamber arms and target drive will be controlled remotely by a computer driven system which will be integrated into the MIDAS software suite. Similarly, the vacuum control will also be incorporated into this software. The chamber will be pumped via two pneumatic 150mm gate valves with two turbo pumps, each with separate roughing pumps. The chamber is also designed to handle up to 350 signals through the vacuum interface, requiring compact but versatile signal feedthroughs such as Socapex and/or Fischer multi-way connectors, as well as a complete installation of patch panels and new cable runs of about 80m from ECLAN to the LISE3 counting room.

For experiments using the fragmentation beams the chamber would probably be mounted on the end of the LISE spectrometer. However, it could also be positioned on other beamlines, especially in operation with SPIRAL beams. An exciting prospect is the LISE200 project, providing a factor of 10 improvements in the intensity of beams from LISE. Thus the chamber can also be sited on the new beamline connected to LISE2000.