Some time ago I’ve won a 63×63 NaI(Tl) crystal for around 80€ at eBay. It is an SDN52 a special crystal designed to be heat and vibration resistant. Let’s build a probe with it and a 76mm photokatode XP2421/SQ PMT

63×63 Scintillator

First problem to solve was how to tightly couple this heavy crystal with this PMT? I’ve solved it with the help of my 3D printer: I’ve designed and printed a fitting with TPU that’s a kind of rubber filament material. STL zip file: gasket  password: madexp

And now let’s put all togheter.

The PMT

The crystal

The assembly

Finally I’ve soldered in place the dynode chain voltage divider PCB.

After covering the tube with black tape I am ready to test it.

The result is a nice 7.5%-8% FWHM @ Cs137 peak