Gamma Spectrometry Forum

I just acquired a high voltage preamp for a helium 3 tube (rather than rewiring a lower voltage version, with the final justification being that I might use the latter at some later date). The high voltage in is, as I would expect, an SHV connector, but the detector input appears to be a regular BNC. Going inside the device there's not actually enough room inside for an SHV (nor an MHV) on the input side owing to the extended insulator. It's just a regular panel-mount BNC.. I'm now a bit confused as from what I gather BNC connectors are rated for an operating voltage of 500V, but the preamp is rated for 2kV.. Is it the case that the BNC plugs will actually take a much higher voltage than the cables themselves prior to breakdown? Is the MHV socket identical to a regular BNC with only the plug being different? The detector I will be using needs just shy of 2kV and I don't want to pop or short anything the first time I plug it in!

Cheers,

Teyen.

Teyen,

It is correct that BNC connectors are rated for 500V, this rating in most cases includes a pretty generous safety margin, but running them at 2kV is pushing it.

It may not fail immediately, but high voltage has a tendency to creep across surfaces over time, I recommend replacing it with a MHV connector if possible.

Steven

Thanks for that. I had a feeling they might have under-engineered the thing.. Looks like the MHV and SHV have similar "tails" on them, so fitting either is going to be a challenge- hopefully not an insurmountable one!

Teyen.