Search found 136 matches

by Maciek Szymanski
Thu Mar 25, 2021 11:17 pm
Forum: Vacuum Technology (& FAQs)
Topic: Ground terminals for HV feedthrough: chamber as return path
Replies: 14
Views: 1379

Re: Ground terminals for HV feedthrough: chamber as return path

Usually I just drill a blind M3 hole from the vacuum side and mount an eye terminal by a small drilled screw, then solder the ground wire to the eye. Unfortunately I don't have any photograph in hand. It is easier to do it if the KF plug is thicker than standard (for the semiconductor TOF detectors ...
by Maciek Szymanski
Thu Mar 25, 2021 7:24 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Scintillators by Nuclear Enterprises
Replies: 6
Views: 362

Scintillators by Nuclear Enterprises

I'm slowly getting into radiation measurement system. Some time ago I've got few British made neutron detectors (from dumpster at work :-) of course). The scintilators are made by Nuclear Enterprises Ltd at Edinburgh probably in 1970s. There are even no information if these are fast or thermal neutr...
by Maciek Szymanski
Thu Mar 25, 2021 6:08 pm
Forum: Vacuum Technology (& FAQs)
Topic: Ground terminals for HV feedthrough: chamber as return path
Replies: 14
Views: 1379

Re: Ground terminals for HV feedthrough: chamber as return path

A side note - on the Asterix laser system in Prague it is required that all the diagnostic systems are insulated from the interaction chamber and grounded independently as required. It's usually achieved by using plastic KF centering rings and clamps or teflon extension tubes. Lately I've built few ...
by Maciek Szymanski
Sun Mar 21, 2021 9:23 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Some unexpected breakdown voltage measurements
Replies: 10
Views: 1214

Re: Some unexpected breakdown voltage measurements

Things are getting more interesting. I've made a solid aluminum cathode. I will make the drawing later, but the cathode is a ball of 35mm diameter with five tapered holes at right angles. The hole diameter at the ball center is 10mm and the taper angle 15º. 85F2C674-C91B-4705-A06D-DCBB892DF9BA.jpeg ...
by Maciek Szymanski
Sat Mar 20, 2021 10:06 pm
Forum: Vacuum Technology (& FAQs)
Topic: Can somebody check my calculations?
Replies: 6
Views: 559

Re: Can somebody check my calculations?

The pV flow is:

q = C*(p1 - p2) = 15,9*(1e-4 - 1e-7) = 15,9*9,99e-5 =1,59e-3 hPa*l/s

Calculating volumetric flow at spectrometer chamber pressure p2:

q_v = q/p2 = (1,59e-3)/(1e-7) = 15900 l/s
by Maciek Szymanski
Sat Mar 20, 2021 7:56 pm
Forum: Vacuum Technology (& FAQs)
Topic: Can somebody check my calculations?
Replies: 6
Views: 559

Re: Can somebody check my calculations?

Thank you for response. The date is a mistake - I've rewriten the calculations in english to post it here, and written a wrong date. The volume of the spectrometer is small compared to the experimental chamber and for the initial calculation do not matter in my opinion. The point of the calculation ...
by Maciek Szymanski
Sat Mar 20, 2021 4:45 pm
Forum: Vacuum Technology (& FAQs)
Topic: Can somebody check my calculations?
Replies: 6
Views: 559

Can somebody check my calculations?

This is not fusor related, but I hope that someone with the vacuum experience can help me. I was asked to calculate gas load for a spectrometer chamber. This is open system with a large slot pumped differentialy (the spectrometer needs better vacuum than the experimental chamber). The calculation is...
by Maciek Szymanski
Wed Mar 17, 2021 9:57 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Some unexpected breakdown voltage measurements
Replies: 10
Views: 1214

Re: Some unexpected breakdown voltage measurements

I really hate to go trough many levels of options and sub-options to get the right looking chart in a computer program. By hand I can add any marks and annotations with just one tool :-) And I can have a really big screen area to view all the data at once: 29D7A216-DAA0-41B7-8D54-E853108235C2.jpeg T...
by Maciek Szymanski
Tue Mar 16, 2021 10:53 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Some unexpected breakdown voltage measurements
Replies: 10
Views: 1214

Re: Some unexpected breakdown voltage measurements

I don't suppose that the cathode temperature is an issue here. The measurements were made with the grid cold and after breakdown I have not increased the current beyond 2 mA. I'm suspecting surface (deposits etc) of the wire. The 0.6 cathode has seen less discharges than 0.8, but anyway before the m...
by Maciek Szymanski
Mon Mar 15, 2021 8:41 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Some unexpected breakdown voltage measurements
Replies: 10
Views: 1214

Some unexpected breakdown voltage measurements

I’ve finally moved from building to experimenting with my garage fusor. (The vacuum system build is here: https://fusor.net/board/viewtopic.php?f=10&t=13708 and the power supply here: https://fusor.net/board/viewtopic.php?f=11&t=13873). As I mentioned earlier I’m interested in ionization mechanisms ...