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New SoCal Effort

Posted: Sun Jan 06, 2019 9:50 pm
by Joe Gayo
Hello everyone,

I’m an engineer in Southern California working on a neutron producing fusor. The device is the ultra-compact variety using KF40 fittings and a Pfeiffer Duo 2.5 pump (only, no diffusion or turbo).

Regards, Joe

Re: New SoCal Effort

Posted: Mon Jan 07, 2019 5:57 am
by Dennis P Brown
Welcome. Good luck with your efforts in building a fusor. I'm not aware of a successful fusor that uses only a mechanical pump. Others will likely have more knowledge and comment on this issue.

Re: New SoCal Effort

Posted: Mon Jan 07, 2019 11:06 am
by Joe Gayo
I found this while searching fusor.net -
"Pressure is still 48-58 mTorr during runs. Base pressure has lowered to 3 mTorr (I'm using just a 2-stage rotary pump)."
viewtopic.php?f=18&t=11318&start=25

So it has been done before ...

Re: New SoCal Effort

Posted: Mon Jan 07, 2019 1:20 pm
by John Futter
Joe
What makes you think that Garret only used a mechanical pump
yes the operating point is above the lowest pressure that a mechanical pump can achieve but the pumping speed is almost zero.
you need vacuums before you start of 10^-5 torr or better to remove as much crud especially water vapor from the system otherwise yo will dilute your gas by as much as 80%
please do a lot more reading

Re: New SoCal Effort

Posted: Mon Jan 07, 2019 2:07 pm
by Richard Hull
10e-4 torr is just fine for most fusor run starts, but the deeper you go, the better and more rapid your results. Running pressures as you admit flowing D2 into the chamber against the ultimate low pressure is 5-25 millitorr.

Richard Hull

Re: New SoCal Effort

Posted: Mon Jan 07, 2019 9:18 pm
by Joe Gayo
John Futter,

I found the pictures of the device you have presumably at GNS:

viewtopic.php?f=18&t=9534

Did you ever run D2 with a Ti target? Just curious.

Re: New SoCal Effort

Posted: Tue Jan 08, 2019 1:02 am
by John Futter
No
I was not allowed to ie no good reason to produce ionising radiation
Although If I wanted to do it over a weekend with another staff member on hand to satisfy safety concerns I probably could. 'Recently I have been running high power carbon beams (Butane gas) in the ion source and ion currents of around 20mA to do DLC coatings, DLC = diamond like coating

I can get 1-2 microns per hour coating thickness of DLC over a 6"diameter so it is quite quick

Re: New SoCal Effort

Posted: Tue Jan 08, 2019 7:06 pm
by Dennis P Brown
Diamond like films - interesting. A few coworkers some years ago grew actual diamond films; they impregnated the surface of a copper plate with diamond dust and then use a method very similar to yours.