As I said its slowly seems to be pumping down. Let it go for 2 weeks. I have had to do that with travelling wave tubes... Cost $2 for electricity. If that doesn't work go for the big guns.
On Sun, Jan 17, 2010 at 5:03 PM, J. Forster <j...@quik.com> wrote: > I just looked at eBay and most everything suitable is well over $200. > > -John > > ============ > > > > The small Bertan modules in particular are extremely stable and > > well-behaved. You get exactly the voltage that you program, accurate to > > within about a tenth of a percent. No spikes, no drift, and no obnoxious > > AF > > whine like you get from the HP modules. > > > > The smaller ones are good for 500 uA, and the larger modules are good for > > 2-5 mA depending on model. > > > > -- john, KE5FX > > > >> -----Original Message----- > >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on > >> Behalf Of J. Forster > >> Sent: Sunday, January 17, 2010 8:00 AM > >> To: Discussion of precise time and frequency measurement > >> Subject: Re: [time-nuts] 4 KV Power Supply Recommendations > >> > >> > >> The small modules are nice, but many PMT supplies do not go to 5 mA. 5 > >> mA > >> @ 4 KV is 20 Watts output, more at the input. That's a lot for a PMT > >> supply. > >> > >> Also, remember that some supplies designed for gas lasers have a HV > >> "kick" > >> at startup that may go to 20-30 KV. > >> > >> -John > >> > >> ============== > >> > >> > >> > > >> >> Since it appears to be making some progress, I'd be tempted to just > >> >> continue. The pump rate of an ion pump varies with the current, so it > >> >> seems you are pumping, just somewhat more slowly than w/ the external > >> >> supply, as long as you are not overloading the internal supply. > >> >> > >> >> If you don't have a lab supply, get an old transformer from some > >> vaccum > >> >> tube gear and use the HV secondary to drive a Cockroft-Walton > >> multiplier > >> >> to get to what you want. Pretty trivial to build these days. Put the > >> >> primary on a Variac to adjust the voltage. > >> >> > >> >> BTW, a commercial supply at that voltage and current is going to cost > >> >> several hundred dollars. > >> > > >> > The nicer Glassman rack-mounted supplies are spendy, but smaller HV > >> > modules > >> > for PMT and laser work are common and inexpensive. Go to eBay > >> and search > >> > for "<manufacturer> supply", where common manufacturers include Emco, > >> > Bertan, Spellman, Fluke, and Glassman. E.g. item 220539685243 . > >> These > >> > smaller modules tend to sell for well under $100, and are handy to > >> have > >> > around. > >> > > >> > -- john, KE5FX > >> > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.