This can save space and cost, especially when resolution is not of importance. The maximum size of a scintillation crystal varies very much between different materials. This has to do with crystal growing physics related to the physical properties of the material. Sometimes it is easier and less expensive to construct a large detector surface area by combining smaller detectors. We always advise to consult us for the optimum detector configuration for your application.
More complicated geometries are possible but add to cost.
Aluminum has excellent radiation transmission properties but is relatively soft and can corrode, even when anodized. All detectors can be provided with customer defined mounting flanges or other means to support the instrument. The light yield of a scintillation material and the gain of a PMT is a function of temperature. Ce in optical contact with the primary scintillation crystal. The advantage of method 1 is that one calibrates on the true response of the primary crystal.