Search found 345 matches

by Jim Kovalchick
Thu Apr 09, 2020 12:28 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor V construction - the process long running
Replies: 33
Views: 2334

Re: Fusor V construction - the process long running

Richard, I'm sorry to hear about the fruits and lack there of, if your efforts. My numbers are bad now, but they started out fairly good. My original numbers were higher on my pnc than they were when I held it against your Fusor IV doing a million per second. I was originally bolstered and remain so...
by Jim Kovalchick
Wed Apr 08, 2020 11:32 pm
Forum: Images du Jour
Topic: Jim Kovalchick -My attempt at smaller fusor
Replies: 41
Views: 4549

Re: Jim Kovalchick -My attempt at smaller fusor

My neutron numbers have been dropping steadily over the last several runs. Today I took a series of measurements at various voltages from 30 to 40 kV with constant current. After I was done I went back to my starting voltage and repeated the measurement. The difference was huge. At -30 kV, 5 mA, and...
by Jim Kovalchick
Tue Apr 07, 2020 2:11 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Help using Canberra 8701 ADC for MCA and *more* Neutron Issues
Replies: 6
Views: 460

Re: Help using Canberra 8701 ADC for MCA and *more* Neutron Issues

Luke, So far there hasn't been much difference with the installation on Windows 10. I am not done yet but my issues are mostly hardware.
by Jim Kovalchick
Sat Apr 04, 2020 11:49 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor V construction - the process long running
Replies: 33
Views: 2334

Re: Fusor V construction - the process long running

I sit my pnc on top of one of my beam end blanks. At 40 kV and 10 mA I get about 750 cpm. The same BF3 tube measured 400 cpm held against your fusor IV doing a million n/sec. I'm sure my total neutrons are less, but the effective neutron flux I can get close to seems higher. I think Jon R said that ...
by Jim Kovalchick
Thu Apr 02, 2020 2:23 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Help using Canberra 8701 ADC for MCA and *more* Neutron Issues
Replies: 6
Views: 460

Re: Help using Canberra 8701 ADC for MCA and *more* Neutron Issues

I have been putting together an MCA system using Jay's write up as Scott mentioned. So far, I have a Windows 10 laptop now talking to a 556A AIM. I have a little more work to do before I'm getting spectra through the system, but with Jay's write up, I have come way further than I did first trying to...
by Jim Kovalchick
Wed Apr 01, 2020 1:03 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor V construction - the process long running
Replies: 33
Views: 2334

Re: Fusor V construction - the process long running

With my cross, the xrays are where you might imagine, the view port and feedthrough. At higher voltages, the cross tubes become transparent. The conflat fittings have some bulk them so that helps except out the beam target ends. I have now wrapped the cross tubes with a double layer of lead for a to...
by Jim Kovalchick
Mon Mar 30, 2020 3:04 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor V construction - the process long running
Replies: 33
Views: 2334

Re: Fusor V construction - the process long running

Richard, Congrats on the new fusor. One nice thing about using air to glow clean is the ability to start your work at lower voltages without having to use a massive chamber pressure to light the plasma. To get 7 kV to light with d you would be pushing over 50 microns in that cross. I have to go high...
by Jim Kovalchick
Sat Mar 28, 2020 10:07 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor V construction - the process long running
Replies: 33
Views: 2334

Re: Fusor V construction - the process long running

Richard,
Have you thought about shielding? The crosses can really scream at 40 kV. Of course, my viewpoint is the worst, but I had to shield the cross itself.

I'm curious about your choice of copper for the grid. You're not worried about melting it?

Jim K
by Jim Kovalchick
Mon Mar 23, 2020 8:33 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Window dressing - Trying to clean view port glass
Replies: 5
Views: 497

Re: Window dressing - Trying to clean view port glass

Richard, you might try annealing the radiation browning. Years ago I had a beer glass that I browned in a big cobalt source. One day, it accidentally was put in the dish washer instead if the usual hand was. The heat dry in the washer eliminated a good bit of the brown. Perhaps your view port could ...