How to make a scintillation probe with aluminium enclosure? Is not that hard if you have a lathe, a mill and a drill. I start assembling the scintillation crystal with the photomultiplier and measuring them. From standard aluminium pipe size, I choose one for the body and one, as reducer, to fit the scintillator inside the body pipe. From an alluminium round bar I made the ened cap.
Body pipe and crystal adapter. It fits inside the body and have a center hole where I put the crystal
This pic is from another probe… as you can see is easy to scale up my design. In this case the aluminium adapter fits a 36mm crystal into a 40mm pipe
Black silicon assembly
How the crystal + adapter fits the pipe
The crystal adapter is a piece of pipe shaped to fit inside the body pipe and have an inner hole where I put the crystal and photomultiplier. I use silicon black glue to gle everything together. It is strong but can be removed easily if I need to re-open the assembly.
Photomultiplier, crystal and front adapter
Silicon grease that will couple the crystal to the PMT front window
To assemble the PMT+crystal I’m using an optical coupling grease.
Coupling
Blocking the assembly with some black electrical tape
Fixing crystal + PMT inside the adapter with black silicon glue
After silicon glue hardened I assemble the voltage divider board to the photomultiplier wires. The divider board is home made etching it’s circuit on a piece of FR4 or bakelite copper clad board.
Front assembly
Voltage divider added
Bakelite voltage divider board
Now that everything is ready, I close the probe adding the end-cap and soldering the voltage divider + and – at the BNC female connector on the ending cap.
Ending cap inner view
Ending cap BNC connector
Usually I anodize my alluminium parts. Using different kind of alluminium alloys for different probe parts results in different color of the anodized surface.
Hi-Zinc content into the alluminium alloy makes it darker than standard aluminium
And this is the final result
