Highly efficient two-dimensional detectors are essential for the performance of modern neutron diffractometers. The NUM Division of PSI and the Technical University Munich TUM jointly develop two identical new 3He gas detectors, one for the diffractometer DMC at SINQ and the other for operation at FRM-II in Munich.
The design is a modification of the detectors currently in operation at the instruments WAND2at ORNL and WOMBAT at ANSTO and reduces the non-active 3He volume, which has become a rare and expensive gas. The Laboratory for Neutron and Muon Instrumentation LIN - with great support from additional groups at PSI - has designed and built two pressure vessels for the gas detectors. The tasks included FEM simulations, design, production and testing. On June 25, the detector tanks were successfully tested by TÜV and certified for operation at 7 bar gauge pressure. This is an important milestone in the detector development project and a major step in the upgrade of DMC.