Search found 651 matches

by Andrew Seltzman
Sun Mar 24, 2019 3:13 am
Forum: Announcements and Site Administration Topics
Topic: web site problem
Replies: 18
Views: 10728

Re: web site problem

Could we modify the "search restrictions" to allow viewing of "active topics" without having to log in?
search.php?search_id=active_topics
by Andrew Seltzman
Sat Mar 23, 2019 7:48 pm
Forum: Ion Gun Design and Construction (& FAQs)
Topic: Anode layer ion source. Operation pictures
Replies: 70
Views: 69901

Re: Anode layer ion source. Operation pictures

I have a mass-producible base-plate design for the anode layer ion source using an aluminum cutout from Front Panel Express IMG_20190320_235610180a.jpg A hermeticallly sealed Pasternack PE4077 BNC connector is used as the HV feedthrough. It's rated to 500v with a dielectric withstanding voltage of 1...
by Andrew Seltzman
Sat Mar 23, 2019 4:42 pm
Forum: Announcements and Site Administration Topics
Topic: web site problem
Replies: 18
Views: 10728

Re: web site problem

I would like to weigh in strongly against #1 "1. Not all categories are visible without being signed in." and suggest that for #2: "2. Search functions and other parsing functions are not accessible without being signed it" should be modified to allow users that are not signed in to search after sol...
by Andrew Seltzman
Sun Mar 17, 2019 5:22 pm
Forum: Announcements and Site Administration Topics
Topic: Commentary on Doing Fusion
Replies: 17
Views: 9444

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
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: 65163

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: 65163

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: 65163

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: 18188

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: 28
Views: 19907

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...