Thermal imaging of fusor grid / plasma

For posts specifically relating to fusor design, construction, and operation.
Andrew Seltzman
Posts: 717
Joined: Mon Feb 02, 2004 1:02 am
Real name: Andrew Seltzman
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Seltzman » Thu Jul 17, 2014 6:37 am

Beam expander assembly to reduce beam to size of optical detector
SAM_3182a.jpg
SAM_3185a.jpg
Test setup, soldering iron as heat source collimated through germanium lens
SAM_3187a.jpg
Shadow viewed on detector
MPEG0003-shadow.jpg
Andrew Seltzman
www.rtftechnologies.org

Andrew Seltzman
Posts: 717
Joined: Mon Feb 02, 2004 1:02 am
Real name: Andrew Seltzman
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Seltzman » Sat Jul 19, 2014 8:16 pm

Direct imaging of expanded 10.6um beam from CO2 laser with thermal imager.

Synrad H48-1 with a 9x beam expander that has an internal adjustable iris to prevent reflection of the over expanded beam off the internal walls of the lens tube that cause a halo around the primary beam. Imaged with a thermal eye 2500AS

Before iris was added
MPEG0000-iris-open.jpg
After iris was added
MPEG0000-iris-filter.jpg
Video of adjusting iris
http://youtu.be/5j9_Yv9_eOM

Germanium rear coupler mirror 99.5% reflective, 0.5% transmissive, used as a 200X power attenuator
SAM_3177a.jpg
Coupler mounted on front of thermal imager beam expander
SAM_3191a.jpg
Laser setup
SAM_3194a.jpg
Laser modulation profile, 6% duty cycle, 1khz square wave, for further reduction in laser power
laser-moda.jpg
Bench test imaging of shadow in beam cast by soldering iron tip
SAM_3196a.jpg
Captured image of shadow
MPEG0003-shadow-direct.jpg
Video of moving metal tip through imaging beam
http://youtu.be/x_UALp30oOA
Andrew Seltzman
www.rtftechnologies.org

Andrew Seltzman
Posts: 717
Joined: Mon Feb 02, 2004 1:02 am
Real name: Andrew Seltzman
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Seltzman » Sat Jul 19, 2014 9:15 pm

Imaging setup running with fusor with no plasma.

Laser setup with fusor
SAM_3198a.jpg
Beam aligned with core input window
SAM_3200a.jpg
Thermal imager viewing beam at output window
SAM_3201a.jpg
Shadow from central grid
MPEG0008-grid1.jpg
Shadow from central grid
MPEG0009-grid2.jpg
Videos of viewing the grid while repositioning the thermal imager
http://youtu.be/ZD-UnhpNOC4
http://youtu.be/N12B16Lp1gw

More pictures at
http://www.rtftechnologies.org/physics/ ... ometer.htm
Andrew Seltzman
www.rtftechnologies.org

Andrew Seltzman
Posts: 717
Joined: Mon Feb 02, 2004 1:02 am
Real name: Andrew Seltzman
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Seltzman » Thu Jul 31, 2014 6:13 am

Preliminary testing of the laser system with plasma.


Setup of fusor with quad ion injector system, vacuum system, and CO2 laser probe
SAM_3247a.jpg
Quad injector power supply, 5kV, 3ma per channel for anode layer ion sources
SAM_3266a.jpg
Ion injector power cables
SAM_3267a.jpg
Starmode with ion injectors
SAM_3258a.jpg
Grid with coolant flow off
MPEG00~1-grid-hot.jpg
grid with coolant flow on
MPEG00~2-grid-cool.jpg
Laser density probe of plasma
MPEG00~3-laser-probe.jpg
Overall the laser probe observed nothing, which was expected at this point since the grid power supply is very under powered (5ma max) and can not bring the plasma density above cutoff at 10.6um. A capacitive pulsed system for the grid, and a interferometer setup for the laser are in progress.

The ion injectors work perfectly, however since they can flood the the entire chamber with plasma, they tend to over power the grid power supply when even one is running at maximum output. One interesting observation, by varying the ion injector power individually, the center of the star can be pushed around the inside of the center grid.
Andrew Seltzman
www.rtftechnologies.org

User avatar
Richard Hull
Moderator
Posts: 11335
Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: Thermal imaging of fusor grid / plasma

Post by Richard Hull » Thu Jul 31, 2014 3:21 pm

Andrew, This is some great data collection effort on your part. I am sure most everyone follows this with great interest. As this progresses and when you feel you might be able to issue a final summary report of your work, please do so. Some of your data already given is most intriguing.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Andrew Seltzman
Posts: 717
Joined: Mon Feb 02, 2004 1:02 am
Real name: Andrew Seltzman
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Seltzman » Sat Aug 30, 2014 2:53 am

Plasma at 5mTorr
SAM_3286ba.jpg
Videos of thermal imaging fusor interior, some at 320x240 resolution, turning on and off grid coolant flow
http://www.youtube.com/watch?v=8suOQDY9668
http://www.youtube.com/watch?v=lxMEJhGmrmA
http://www.youtube.com/watch?v=UUihlkrJeQw
http://www.youtube.com/watch?v=8DfPozHL37A

Interferometer beam splitter mount
SAM_3298a.jpg
Grid viewed through interferometer beam splitter
SAM_3300a.jpg
Interferometer reference beam arm
SAM_3305a.jpg
Interferometer reference beam arm
SAM_3306a.jpg
Turning mirrors
SAM_3310a.jpg
All updates so far
http://www.rtftechnologies.org/physics/ ... ometer.htm
Andrew Seltzman
www.rtftechnologies.org

Andrew Seltzman
Posts: 717
Joined: Mon Feb 02, 2004 1:02 am
Real name: Andrew Seltzman
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Seltzman » Fri Sep 19, 2014 5:48 am

Construction of the grid mounted ion collector to measure the distribution of ions hitting the grid surface based on temperature rise of each segment is complete.

Copper disk with one segment machined
SAM_3334a.jpg
Machining down center thickness to 0.2mm
SAM_3342a.jpg
Machining ion collector
https://www.youtube.com/watch?v=ZUyIb7z ... e=youtu.be

Ion collector segments
SAM_3348a.jpg
Ion collector mounted on grid
SAM_3361a.jpg
Ion collector mounted on grid
SAM_3362a.jpg
Ion collector mounted on grid, grid installed in reactor
SAM_3364a.jpg
Andrew Seltzman
www.rtftechnologies.org

Andrew Seltzman
Posts: 717
Joined: Mon Feb 02, 2004 1:02 am
Real name: Andrew Seltzman
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Seltzman » Fri Oct 03, 2014 3:56 am

Report on findings so far
seltzman_us-japan-2014.pdf
(2.58 MiB) Downloaded 259 times
Andrew Seltzman
www.rtftechnologies.org

User avatar
Andrew Robinson
Moderator
Posts: 677
Joined: Sun Aug 11, 2013 5:54 am
Real name: Andrew Robinson
Location: Raleigh, North Carolina
Contact:

Re: Thermal imaging of fusor grid / plasma

Post by Andrew Robinson » Mon Oct 06, 2014 5:39 pm

Impeccable work Andrew. I am following your efforts with great interest.
I can wire anything directly into anything! I'm the professor!

User avatar
Ben_Barnett
Posts: 24
Joined: Tue Sep 25, 2018 9:06 pm
Real name: Ben Barnett

Re: Thermal imaging of fusor grid / plasma

Post by Ben_Barnett » Thu Jan 24, 2019 8:34 pm

A 1 inch (25.4 mm) Zinc Selenide window costs ~$300 USD, and the thermal camera comes up around $500.

Is there a way to do thermal imaging of the fusor grid (to determine plasma/grid temperatures) for under $300 - $400?

Or maybe someone can point me in a different direction.
We are aiming to vary the grid geometry in the fusor, and take measurements to compare the effects of the different geometries. Aside from input voltage, current, and chamber pressure, if possible a measurement of the plasma temperature would be great if for a reasonable price.

Post Reply