Page 15 of 15

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

Posted: Sat Feb 02, 2019 1:30 pm
by Dennis P Brown
Nice apparatus! A side possibility; you can get single crystal silicon wafers super cheap (even select from the company what plane it was cut - 001, 011 etc.). Set it at the correct angle relative to your camera (maybe a micrometer rotation mount) and use it to get specific energies from the electron x-rays. The wafer need not be in the vacuum just line of sight to the x-ray source. Closer, of course, the better.

A side thought: one could "focus' the x-rays by placing the wafer on a circular vacuum ring and apply a moderate vacuum to deform the wafer into a spherical surface. This will weakly focus grazing x-rays off its front surface to "image" the source and provide an energy spectrum.

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

Posted: Sat Feb 02, 2019 4:54 pm
by Andrew Seltzman
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.

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

Posted: Sun Feb 03, 2019 5:07 am
by Andrew Seltzman
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_185019702a.jpg
Picture taken with a 1.5mm pinhole for 30s:
1.5mm 30s.png
Picture taken with a 1.0mm pinhole for 30s:
1.0mm 30s.png
Picture taken with a 0.5mm pinhole for 60s:
0.5mm 60s.png
Picture taken with a 0.5mm pinhole for 60s (brightened):
0.5mm 60s bright.png
Reducing the pinhole size noticeably sharpens the image at the expense of intensity.