Search found 842 matches

by Jerry Biehler
Mon Feb 18, 2019 6:00 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: A semi-DIY preamplifier for radiation detectors
Replies: 5
Views: 242

Re: A semi-DIY preamplifier for radiation detectors

You could use a cheapish isolated DC/DC converter module. They have basically no ripple. You definitely wont see any 60hz!
by Jerry Biehler
Mon Feb 11, 2019 5:12 am
Forum: Vacuum Technology (& FAQs)
Topic: Poor performance of old diff pump.
Replies: 11
Views: 1293

Re: Poor performance of old diff pump.

The gauge heads ought to be able to be cleaned to get them working again. I would probably start by washing them out with mineral spirits to dissolve the oil and then acetone. I would be surprised if the filament on the ion gauge ever even turned on at the pressure you were getting.
by Jerry Biehler
Wed Jan 16, 2019 7:52 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Integrated Lab Measuring and Controlling (Labview, Labjack, ...)
Replies: 38
Views: 2470

Re: Integrated Lab Measuring and Controlling (Labview, Labjack, ...)

No, I didn't hack the sensors, they come with analog out as standard, in the manual they tell you how to decode the voltage signal to get useful information. I just apply the math in labview and I get my pressure reading out. I have a 2465 too, good scope. If it is the original 2465 they have an iss...
by Jerry Biehler
Sat Jan 12, 2019 2:05 am
Forum: FAQs: Vacuum Technology
Topic: FAQ - Never turn on a turbo or diff pump until....!!!
Replies: 2
Views: 395

Re: FAQ - Never turn on a turbo or diff pump until....!!!

If you are direct pumping to a chamber with a turbo you can start the roughing pump and turbo at the same time with newer turbos. Even says so in the manual, they are power limited and will not come up to anywhere close to speed until they have a good enough vacuum to run. I would still pump down a ...
by Jerry Biehler
Fri Jan 11, 2019 9:06 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Integrated Lab Measuring and Controlling (Labview, Labjack, ...)
Replies: 38
Views: 2470

Re: Integrated Lab Measuring and Controlling (Labview, Labjack, ...)

I used labview to control my vacuum system that I have been building for ebeam deposition. I needed to talk to things like my VAT valve which is controlled through RS-232 so it was really the simplest way. I used something similar to a labjack to handle the analog outputs from the pressure sensors I...
by Jerry Biehler
Fri Jan 11, 2019 8:48 am
Forum: The Trading Post
Topic: End of HSC (Halted Specialties) electronics surplus store in Santa Clara, CA
Replies: 2
Views: 453

Re: End of HSC (Halted Specialties) electronics surplus store in Santa Clara, CA

I went there when I was down in the area summer of 2016 when they had just moved into the new location. Tiny and a lot of high prices. That and rent just squeezed them out. They offered to sell out to a friend of mine who runs SurplusGizmos up here but he just can't justify it. I hit Excess Solution...
by Jerry Biehler
Sat Jan 05, 2019 1:01 am
Forum: New User Chat Area
Topic: Someone give me some exact specs
Replies: 19
Views: 1317

Re: Someone give me some exact specs

You are not ever going to break even with a fusor, just not happening. Uranium is not a big deal, it is mostly an alpha emitter which does not even make it through your skin, about the only time you need to really worry about it is if you ingest or inhale it. The x-rays from a fusor at 40kv are way ...
by Jerry Biehler
Tue Jan 01, 2019 11:23 am
Forum: Vacuum Technology (& FAQs)
Topic: The Importance of TC Gauge Calibration
Replies: 10
Views: 1525

Re: The Importance of TC Gauge Calibration

The 531 is a full range tube, 1 mtorr to atm, can't tell what the other tube is but it may have a shorter range which will give better accuracy at the lower end. But are you sure the televac controller and the tube you have matches?
by Jerry Biehler
Tue Jan 01, 2019 11:15 am
Forum: New User Chat Area
Topic: Someone give me some exact specs
Replies: 19
Views: 1317

Re: Someone give me some exact specs

You could put together a part list to make a fusor, but it wont be possible to do it under $1000, possible an order of magnitude larger. With this kind of stuff it is pretty difficult to find an exact part used so you have to scrounge, find used, modify, etc to keep the costs down. When you have par...
by Jerry Biehler
Fri Dec 21, 2018 5:54 am
Forum: New User Chat Area
Topic: Regrind the seal face of a flange of a turbo pump for better vacuum
Replies: 4
Views: 448

Re: Regrind the seal face of a flange of a turbo pump for better vacuum

I doubt if you even need any grease. Worse case you can sand any scratches smooth. O-rings are compliant, they dont care too much about flat, sharp scratches are the biggest problem.