POLDI upgrade with a ZnS/6LiF scintillation detector
The new detector is developed by the MSS group, in collaboration with the detectors group and the electronics and measuring systems group of the laboratory for particle physics at PSI.
A detection module will possibly consist of 4 sandwiches made of two ZnS/6LiF scintillating layers sandwiching an array of wavelength shifting fibers. The fibers belonging to the same channel are grouped toghether and coupled to a silicon photomultiplier. The use of Silicon photomultipliers instead of photomultiplier tubes is motivated by their high packing fraction and their insensitivity to magnetic fields, two important characterisitcs in this project since the space in the POLDI experimental area is very limited and tests of samples in high magnetic fields are foreseen.
|Current detector||New detector|
|Module size||1 x 0.2 m²||1 x 0.2 m²|
|Number of modules||1||4|
|Horizontal coverage||2θ=75º to 105º||2θ=75º to 105º|
|Spatial resolution||2.5 mm||2.5 mm|
|Detection efficiency at 1.2 Å||65%||65%|
|Time resolution||< 2 μs||< 2 μs|
|Sustainable count rate||4 kHz / ch||4 kHz / ch|
|Gamma sensitivity||No issue||< 10-6|
|Background rate||0.003 Hz / ch||0.003 Hz / ch|