New mini neutron detector from U of Nebraska?

[TBenson]

Did somebody already post this?

http://www.newswise.com/articles/2002/7 ... R.NEB.html

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"The detector, built around a boron-carbide semiconductor diode smaller than a dime, can detect neutrons emitted by the materials that fuel nuclear weapons.

"This is a leapfrog technology in neutron detection," said Peter Dowben, UNL physicist who was the first to fabricate a boron carbide semi-conductor. Using Dowben's boron carbide semiconductors, the research team built a detector about the size of a Lego block that is much more efficient, lighter, and tougher than existing detectors. "

Oh, and here is another one...

http://www.er.doe.gov/feature_articles_ ... tector.htm

Seems like a horse race, each side trying to get money to commercialize.

[Richard Hester]

Both of these detectors look to be tailored for thermal neutron detection (boron, lithium as active materials), so you still need a big, fat moderator to detect fast stuff.

[DaveC]

Is there any reason to expect Silicon Carbide semiconductors might also respond to neutrons?

One can buy SiC single xtal wafers...not sure of current price... but seems to be coming down. Also I believe the blue LEDS are silicon carbide. Wouldn't be hard to check with a known neutron source.

Dave Cooper

[Richard Hester]

Newer blue leds are GaN or GaN on SiC. The chip size is too small to be of real use as a detector. A better choice might be to butt a piece of mylar (proton radiator) up against a silicon detector. The efficiency probably won't be so hot, as the mylar must be thin enough so that a substantial portion of the recoil protons can get out.

[Carl Willis]

Because of the tiny dimensions of the available single-crystal, relatively defect-free SiC, I doubt it would be useful for neutron detection.

However, I have tried some experiments with SiC rectifiers sold by MicroSemi to see if they will work as beta detectors. No luck. I reverse-biased them to their PIV of about 200 V, through a 1 MOHM resistance; and used a preamp and MCA to look for pulses. Nothing at all (I used a highly radioactive piece of Katanga pitchblende for testing). They are very small, which is undoubtedly part of the problem. SiC should work nicely in principle since it is a high bandgap semiconductor. I might try to get a bigger piece and try again.

[DaveC]

We have some 50 mm diameter doped SiC single crystal wafers about 0.5 mm thick, plus some wafer scraps. I know the wafers make excellent electron screens... glowing bright blue. As yet have not tried them for detection of other particles.

Dave Cooper