The scintillation crystals can be customized by adjusting its chemical composition to optimize its performance for a specific application. For example, adding a small amount of dopant that can enhance the crystal's light output, like Thallium doped Sodium Iodide NaI(Tl) and Cesium Iodide CsI(Tl). Even alert the decay time of scintillation process, like Yttrium doped Barium Floride BaF₂-Y. Co-doping with multiple elements can enable adjustments to the energy response or improve the scintillation efficiency, like Calcium co-doped LYSO(Ce) LYSO(Ca, Ce).

To detect nuclear radiation with a certain efficiency, the dimension of the scintillator should be chosen such that the desired fraction of the radiation is absorbed. The thickness of a scintillator can be used to create a selected sensitivity of the detector for a distinct type or energy of radiation. For example thin (e.g. 1 mm thick) scintillation crystals have a good sensitivity for low energy X-rays but are almost insensitive to higher energy background radiation. Large volume scintillation crystals with relatively thick entrance windows do not detect low energy X-rays but high energy gamma rays are measured efficiently.

Surface treatments such as cutting, lapping, polishing(mechanic and chemical) or coating can be applied to crystals to minimize light scattering, improve its light collection efficiency and acquire good uniformity as well as good energy resolution. For example, a customized scintillation crystal may be grinding into a specific particle size(µm) with different sandpaper W14, W20 or W28 etc. It may also be required mechanic polished to increase the amount of photon that reaches to light sensors, or chemically polished to improve its transparency, S/D and improve the uniformity of the scintillation response across the crystal surface.

Reflector materials, such as Magnesium Oxide(MgO), Titanium Dioxide(TiO₂), Barium Sulfate(BaSO₄), Enhanced Specular Reflector(ESR,3M) or Teflon, when it come to apply on single scintillation crystals, the light collection efficiency can be enhanced. And those reflectors can be applied into pixellated crystals to minimize the cross talk from pixel into neighboring ones. For example, BaSO₄ and ESR used in LYSO(Ce) and BGO for PET/SPECT application, TiO₂ in CsI(Tl), CdWO₄ and GOS for industrial CT or X ray security inspection. And special materials like Lead(PB) or Tungsten(W) were added together to achieve desirable results.

The scintillation crystals can be customized with a specialized encapsulation that optimizes their performance and protects it from environmental factors such as humidity, temperature, shock and vibration. For example the hygroscopic NaI(Tl), LaBr₃(Ce) and CeBr₃, all of them require aluminum housing and optical window to prevent them from moisture attacks. While during the applications with harsh conditions, such as measurement while drilling(MWD), in which it always involve high temperature, shock and vibration, special package by SS or Titanium housing with welded glass is necessary. 

The choice of photo-detector depends on factors like the desired sensitivity, dynamic range, and timing resolution. PMTs and SiPMs are commonly used in scintillation detectors, and customization involves selecting the appropriate photodetector type and size based on the application requirements.

The scintillation crystal needs to be coupled to the photodetector to ensure efficient light collection. Customization can involve selecting an appropriate coupling material, such as optical grease or optical adhesive, and optimizing the geometry of the crystal and photodetector interface to maximize light transmission.

Customization can involve designing or selecting signal readout electronics tailored to the specific requirements of the scintillation detector. This includes preamplifiers, amplifiers, discriminators, and digitizers. The electronics can be optimized for parameters such as gain, noise performance, and timing resolution.