Tensioned Metastable Fluid Detector (TMFD)
Re: Tensioned Metastable Fluid Detector (TMFD)
That indeed is how the acoustic TMFD works as well as the bubble detector tubes.
Re: Tensioned Metastable Fluid Detector (TMFD)
The ATMFD looks like something within the realm of the home brew builder. Even if one had to buy the transducers, they are not outrageously expensive, and the driver electronics could be pretty simple (the published version used about 4.5 watts of 18.3 kHz power). Oscillator and amplifier kit modules (e.g. Velleman kits) should work. If there is someone among the readers knowledgeable in ultrasonic acoustic design, they might have a suggestion for a simpler resonant cavity that could be used.
-
- Posts: 147
- Joined: Wed Jun 28, 2006 7:17 pm
- Real name: Silviu Tamasdan
- Location: Connecticut
Re: Tensioned Metastable Fluid Detector (TMFD)
I suspect that the design of a resonant cavity will be strongly depemdent on the working fluid chosen, in particular of the speed of sound in said fluid.
There _is_ madness to my method.
Re: Tensioned Metastable Fluid Detector (TMFD)
The speed of sound in the fluid will definitely affect the reflector spacing. I failed to mention that they used acetone as the fluid in the ATMFD.
- Finn Hammer
- Posts: 298
- Joined: Sat Mar 05, 2016 7:21 am
- Real name: Finn Hammer
- Contact:
Re: Tensioned Metastable Fluid Detector (TMFD)
Dan,Dan Knapp wrote: ↑Sun Oct 22, 2017 4:59 pm
The TMFD shown at the meeting is being used by Kai Masuda’s group at Kyoto University in a detection system for “special nuclear materials” being developed for the Tokyo Olympic Games. They are using a portable fusor with a 17 cm diameter water cooled chamber operated at 120 kV to generate 5 X 10e7 neutrons per second to actively interrogate suspicious objects.
"a 17 cm diameter water cooled chamber operated at 120 kV to generate 5 X 10e7 neutrons per second"
I cannot seem to get my mind off these numbers, and have to ask: What is in the center of that 170mm diametre fusor.
What does a grid supporting this power level look like?
And do you have any data describing the current and pressure in that fusor.
Cheers, Finn Hammer
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 years, and Masuda has made other meeting presentations on this work; so a Google search might yield more details.
Re: Tensioned Metastable Fluid Detector (TMFD)
The following paper is available online:
http://www.taka.qst.go.jp/tokai_center/ ... 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 avoid melting the whole thing at these power levels). The operating pressure is not stated.
http://www.taka.qst.go.jp/tokai_center/ ... 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 avoid melting the whole thing at these power levels). The operating pressure is not stated.
-
- Posts: 147
- Joined: Wed Jun 28, 2006 7:17 pm
- Real name: Silviu Tamasdan
- Location: Connecticut
Re: Tensioned Metastable Fluid Detector (TMFD)
That seems to be a different device though. The chamber diameter is about 3 times bigger (56cm vs the stated 17cm). Even the grid is 20cm diameter.
There _is_ madness to my method.
- Finn Hammer
- Posts: 298
- Joined: Sat Mar 05, 2016 7:21 am
- Real name: Finn Hammer
- Contact:
Re: Tensioned Metastable Fluid Detector (TMFD)
Dan,Dan Knapp wrote: ↑Wed Nov 01, 2017 4:16 pm The following paper is available online:
http://www.taka.qst.go.jp/tokai_center/ ... Ohgaki.pdf
Thank you, for taking the time to dig out this PDF. I appreciate it.
Cheers, Finn Hammer