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.
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4851-1024x768.jpg)
Body pipe and crystal adapter. It fits inside the body and have a center hole where I put the crystal
![](https://madexp.com/wp-content/uploads/2019/07/8CB7367B-8D68-4771-8A83-19079168B71F-e1562560362631-576x1024.jpg)
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
![](https://madexp.com/wp-content/uploads/2019/07/1-576x1024.jpg)
Black silicon assembly
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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.
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4864-1024x768.jpg)
Photomultiplier, crystal and front adapter
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4865-1024x768.jpg)
Silicon grease that will couple the crystal to the PMT front window
To assemble the PMT+crystal I’m using an optical coupling grease.
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4866-e1562392484254-768x1024.jpg)
Coupling
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4867-e1562392520430-768x1024.jpg)
Blocking the assembly with some black electrical tape
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4870-e1562392611822-768x1024.jpg)
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.
![](https://madexp.com/wp-content/uploads/2019/07/28D4EEBA-E178-4D7C-B4A7-6D7E300B0C8F-1024x576.jpeg)
Front assembly
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4873-1024x768.jpg)
Voltage divider added
![](https://madexp.com/wp-content/uploads/2019/07/39950D42-A4FB-4AD3-AF9B-95D955958103-e1562392806641-576x1024.jpeg)
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.
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4852-1024x768.jpg)
Ending cap inner view
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4853-1024x768.jpg)
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.
![](https://madexp.com/wp-content/uploads/2019/07/IMG_4855-1024x768.jpg)
Hi-Zinc content into the alluminium alloy makes it darker than standard aluminium
And this is the final result