This is a cool tube! The MSTR-4 is a mica end-window all glass geiger tube. Is so rare to find out there but once you can find one the problem is shipping, is so fragile! Is extremly sensible, the seller told me that it’s natural background is 25000CPM!!! I need to test it but… the trouble that it need 1200V to operate. Some photo and info sight down there on the page.
- Working Voltage 1200V – 1350V
- Plateau Length 200V Plateau Slope 5% / 100V
- Interelectrode Capacitance 25pF
- Load Resistance 8 – 15 MOhms
- Working Temperature Range +5 +35 С
- Length 180 mm
- Diameter 35 mm
Take care about the round electrodes. They could easily be detached from the glass if handled roughly. Don’t try to solder on it contacts or the glass will break. Use round clip from a PCB fuse holder.
The mica window makes this tube to be very sensible. It can detect weak alpha rays too!
Stay tuned, I’ll try to feed his 1.2Kv needs and make a video of it @ work.