Constructing and commissioning of a Multi-Grid neutron detector prototype for the European Spallation Source

Sammanfattning: A prototype of a novel 10B-based neutron detector called the Multi-Grid detector has been constructed, tested and commissioned for the European Spallation Source (ESS). The detector is constructed after the specifications set by the CSPEC instrument at ESS and is therefore called the CSPEC Multi-Grid detector. The detector uses multiple layers of solid coating containing 10B4C on the edges of a voxelated proportional counter gas detector. The detector was constructed at the ESS detector workshop Utgård in Lund. Initial tests were also performed at Utgård to ensure the functionality and initial state of the detector. It was then moved to the Source Testing Faculty at the Division of Nuclear Physics at Lund University to test the detector with moderated neutrons and with gamma-rays from radioactive sources. Lastly the detector was commissioned at LET, ISIS, for comparison between the detector and the 3He detectors used in the LET instrument. The tests performed in Lund demonstrated that the Data Acquisition System (DAQ) of the detector and the detector itself was functioning, a discrimination threshold for discriminating gamma-rays was found, as well as that the detector is sensitive to neutrons. The tests performed in LET confirmed that the detector can be used for time-of-flight measurements in the energy range required by the CSPEC instrument, furthermore both line-shape and signal to background ratio of the CSPEC Multi-Grid detector was comparable to the 3He detectors.