Search found 684 matches

by Andrew Seltzman
Sun Mar 17, 2019 5:22 pm
Forum: Announcements and Site Administration Topics
Topic: Commentary on Doing Fusion
Replies: 16
Views: 1294

Re: Commentary on Doing Fusion

I feel that 17 may be a bit high for the minimum cutoff, I would propose 9th grade. Historically fusors have routinely competed in, and done well in the Intel science and engineering fair. 9th grade is the minimum entry grade for the ISEF fair. The astute 9th grader (certainly not all, but definitel...
by Andrew Seltzman
Mon Feb 18, 2019 1:34 am
Forum: New User Chat Area
Topic: Converting CPM to neutron flux
Replies: 7
Views: 630

Re: Converting CPM to neutron flux

Hi Joshua, There's no easy way to calculate the conversion from CPM to neutron flux from the tube sensitivity since it depends on things like energy and moderator geometry. You need to test your neutron counter with a known reference. In my case I calibrated my detector against a known calibrated ne...
by Andrew Seltzman
Sun Feb 03, 2019 5:07 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Mark3 operation 3e-4 torr / quad ion source @ -40kV, 1mA-9mA
Replies: 142
Views: 44581

Re: Mark3 operation 3e-4 torr / quad ion source @ -40kV, 1mA-9mA

Some upgrades to the x-ray camera now include: Diffrent molybdenum pinhole sizes 1.5mm, 1.0mm, 0.5mm to sharpen the image IMG_20190202_184858028a.jpg A 3D printed sensor holder to allow zooming in by varying the distance from the sensor to the pinhole IMG_20190202_185341488a.jpg IMG_20190202_1850197...
by Andrew Seltzman
Sat Feb 02, 2019 4:54 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Mark3 operation 3e-4 torr / quad ion source @ -40kV, 1mA-9mA
Replies: 142
Views: 44581

Re: Mark3 operation 3e-4 torr / quad ion source @ -40kV, 1mA-9mA

I'm planning to do something similar for energy. I have some CZT detectors which I'll mount on an x-y drive to position over the part of the image that I want to probe the energy at.
by Andrew Seltzman
Sat Feb 02, 2019 5:09 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Mark3 operation 3e-4 torr / quad ion source @ -40kV, 1mA-9mA
Replies: 142
Views: 44581

Re: Mark3 operation 3e-4 torr / quad ion source @ -40kV, 1mA-9mA

I have recently added an x-ray camera to one of the fusor's viewports to image the locations electrons are striking the shell through bremsstrahlung intensity distributions. The x-ray sensor is a Hamamatsu S10814 CsI crystal needle array coated on top of a fiber optic plate collimator/shield coupled...
by Andrew Seltzman
Thu Jan 31, 2019 12:20 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Spectrum Recorder PCI-E Card?
Replies: 39
Views: 3510

Re: Spectrum Recorder PCI-E Card?

Some things to think about: You are trying to digitize a stochastic, non-repetitive signal. Frequency domain methods (eg a spectrum analyzer) will not be of much use. The Nyquist rate is the BARE MINIMUM frequency that is theoretically required to reconstruct a REPETITIVE signal. 20 points per perio...
by Andrew Seltzman
Sat Jan 26, 2019 4:19 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Thermal imaging of fusor grid / plasma
Replies: 23
Views: 7424

Re: Thermal imaging of fusor grid / plasma

The Zinc Selenide (ZnSe) lens will replace the glass viewport and seal to the conflat flange with a viton o-ring. ZnSe is transparent in the IR wavelengths, so it will let the thermal camera see into the fusor. You can also use a germanium viewport like I am currently using on the latest upgrade: ht...
by Andrew Seltzman
Fri Jan 25, 2019 4:31 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Thermal imaging of fusor grid / plasma
Replies: 23
Views: 7424

Re: Thermal imaging of fusor grid / plasma

Hi Ben, Seek thermal makes a usb thermal camera for a little over $100 https://www.ebay.com/itm/Seek-Thermal-Compact-XR-BLACK-Infrared-Imaging-Camera-For-Android-UT-AAA/123271639865?hash=item1cb38ff339:g:TwgAAOSwfztbWK3D:rk:2:pf:0 For the window look for ZnSe laser cutter lenses on ebay, you can get...
by Andrew Seltzman
Wed Jan 02, 2019 6:54 pm
Forum: Ion Gun Design and Construction (& FAQs)
Topic: Anode layer ion source. Operation pictures
Replies: 62
Views: 29120

Re: Anode layer ion source. Operation pictures

A patent has been granted on the use of a keep alive electrode to decrease startup time:
http://pdfpiw.uspto.gov/.piw?PageNum=0& ... LRPgD8lPts