Search found 150 matches

by Dan Knapp
Sun Dec 31, 2017 12:38 pm
Forum: New User Chat Area
Topic: Glazed porcelain vacuum container?
Replies: 1
Views: 74

Re: Glazed porcelain vacuum container?

It would depend upon the quality of the glazing. Glazed porcelain is used extensively on vacuum feedthroughs. A glazed porcelain container not made specifically for vacuum use would have a high probability of having pinhole defects, but if you were willing to invest the effort to find the defects, y...
by Dan Knapp
Thu Dec 28, 2017 2:47 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Matsusada Power Supply Cable
Replies: 12
Views: 351

Re: Matsusada Power Supply Cable

You can easily make this type of cable yourself from some RG-8 coax and a PL-259 plug. First attach a banana plug to a metal rod and stick it into the receptacle to measure the needed insertion length. Drill out the center conductor and insulation from the PL-259 plug. Strip enough outside insulatio...
by Dan Knapp
Wed Dec 20, 2017 3:37 am
Forum: New User Chat Area
Topic: Pfeiffer Duo 2.5 Question
Replies: 13
Views: 446

Re: Pfeiffer Duo 2.5 Question

I have a Duo 2.5 that overheats and trips the motor thermal cutoff after about an hour of running (Baldor motor). I’ve tried the obvious of replacing the capacitors, but this did not cure the problem. It appears that the pump is putting an abnormal load on the motor. has anyone else encountered this...
by Dan Knapp
Thu Dec 14, 2017 12:48 pm
Forum: Fusor and/or General Fusion Theory (& FAQs)
Topic: Fusor without inner grid?
Replies: 13
Views: 1871

Re: Fusor without inner grid?

In the area of fusion, like many areas of science, there is not much really new under the sun. It is unfortunate that so many of the people with a “new” idea are unemcumbered by prior work. The “Fenley fusor” looks a lot like the “periodically oscillating plasma sphere (POPS)” that was studied exten...
by Dan Knapp
Sun Dec 03, 2017 6:40 pm
Forum: New User Chat Area
Topic: Pfeiffer Duo 2.5 Question
Replies: 13
Views: 446

Re: Pfeiffer Duo 2.5 Question

I would be very cautious working on this pump if you don't have good information on its history. The additional KF port could have been a vent if the pump was used on a system with toxic gases.
by Dan Knapp
Sat Nov 25, 2017 3:23 am
Forum: The Trading Post
Topic: Conflat to Glass Adapter
Replies: 7
Views: 371

Re: Conflat to Glass Adapter

A cheap source of a 2.75CF to glass adapter is a burned out Bayard-Alpert gauge tube on a 2.75CF if a 3/4” glass tube is big enough.
by Dan Knapp
Sat Nov 11, 2017 9:32 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: What do you need to do to run a vacuum system unattended
Replies: 6
Views: 331

Re: What do you need to do to run a vacuum system unattended

I routinely leave vacuum systems running with no provision for handling a power failure (I've been lucky not to have a problem). I recently had a forevacuum pump motor overheat and activate the thermal cutoff, but I was standing nearby and responded. This may indicate I have used up my luck and need...
by Dan Knapp
Fri Nov 10, 2017 3:19 am
Forum: New User Chat Area
Topic: Diff pump
Replies: 19
Views: 604

Re: Diff pump

You can easily improvise a viewport with just a piece of thick glass and an o-ring on one of your chamber flanges (ideally a flange facing up).
by Dan Knapp
Wed Nov 01, 2017 8:16 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Tensioned Metastable Fluid Detector (TMFD)
Replies: 18
Views: 758

Re: Tensioned Metastable Fluid Detector (TMFD)

The following paper is available online: http://www.taka.qst.go.jp/tokai_center/lcs/wp-content/uploads/2017/01/IEEE-TNS-2017-Ohgaki.pdf It shows a diagram and a picture of the cathode of an IEC neutron source that gave 1.2 x 10e8 n/sec operating at 190 kV and 36 mA in pulsed mode (likely key to avoi...
by Dan Knapp
Wed Nov 01, 2017 6:11 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Tensioned Metastable Fluid Detector (TMFD)
Replies: 18
Views: 758

Re: Tensioned Metastable Fluid Detector (TMFD)

In previous reports, they used a spherical grid cathode made from molybdenum sheet material rather than wire, so I assume that is what they are using now. I don't have any specific information on the current and pressure they are using. They have been working on compact neutron sources for several y...