| Popis: |
Future high luminosity spallation neutron sources put strenuous demands on detector performance. This research has focused on applying the Gas Electron Multiplier (GEM) to meet most criteria, most notably mm spatial resolution, 1 MHz local countrate (per pixel) and 70% efficiency for 0.18 nm neutrons. The choice for this detector type was made based on the advantages in both local and global countrate the GEM has over wire-based detectors, in part due to the possibility to implement a 2D pixel readout. Because the high required spatial resolution implies working at a high partial pressure of stopping gas in a He-3 filled detector, the behaviour of the GEM at high pressure was investigated in a series of possible stop gases. One of these gas mixtures (xenon-trimethylamine or Xe/TMA) allows operation at a high enough gas gain with a proposed 1D prototype with 1 mm spatial resolution, which is ready for construction complete with readout electronics. |
