PMT Help/Information.

[James Luck]

Hello all,

As one who frequents Ebay quite often i found a deal I couldn't resist, but now its coming back to bite me.
I came across some Hamamatsu photomultiplier tubes that was new old stock and relatively cheap, couldn't resist buying and stocking up. Although I haven't been able to find a definitive Spec sheet for them. I originally thought they were gonna be like my go to small PMT's P/N: R1166p, although i was mistaken.

These are the same sized as the Hamamatsu R1166p and appear to share the same window type.
size: 19x90ish mm.

The unknown PMT type is P/N:6812241 on box.

I have been unsuccessful at pulling any good documentation on them. closest i got was a sheets saying the unknown type shares the same pinout as the R1166p. After asking around i got mixed information from others that all seem to point to people making assumptions that these are just rebranded R1166p's.

I did hook two up with a 10Mohm divider chain and started at 300v then worked my way up to 1200v while using a BC412 block and a cesium source to try and test its preferred voltage, but i never received any counts. which makes me suspect that either these do not share the same pinout, or that i got a bad batch, although as for vacuum tubes and even PMT's they appear to be fine. I did have one send a signal in a vary brief test where i used a UV lamp to test its sensitivity to UV light but of course long duration it bad, and at that point i was irritated and didn't mind risking killing one.


well any help locating documents on them or trouble shooting will be appreciated, take care.