W-187 Spectrum with FWT Rainbow

[Geoff]

Here is a spectrum of tungsten 187 that I made with a 7.5Ci AmBe source. 20e8 neutrons per second for 12 hours. Spectrum collected for 6 hours, no background subtracted. My set up resulted in very little background, using two tungsten metal shields to surround the detector and a bag of lead shot to cover the end. Far West Technology Rainbow I model 7010 MCA and 1 inch NaI (Tl) detector.

The small grey metal to the right is the sample.

[Steve Dubyk]

Interesting spectrum....how pure is the tungsten sample? There is a Fe-59 peak at 192 keV, could the sample be ferro tungsten? Ferro tungsten is a common commodity.

Steve Dubyk

[Sesselmann]

Geoff, thanks for bringing us some cool neutron activation spectra. That's quite a hot neutron source you are playing with over there, hope you are keeping it at a safe distance. What were you using as a neutron oven or moderator?

What detection equipment do you have for detecting neutrons?

Recently there were some small Li6 scintillators for sale on eBay, I picked up a couple and made nice neutron detectors to work with the GS. I don't have a source myself, but there is a 2.5 x 10^6 AmBe source at University of Sydney, which I can get access to if I need it.

[Geoff]

I suspected it was Fe 59. The sample is a broken piece of a tungsten carbide bushing. I don't know the exact composition, but iron is a common additive.

The handling tool I use is 15 feet long. The source was loaded in to a water tank and water was the moderator. I also had 10 and 12 Ci AmBe sources at work. My primary neutron detector was a Ludlum model 12-4 REM Ball. Now that I'm unemployed, I don't have a neutron detector or source. I'm going to mix up an RaBe source, but need to make a detector first. I have an He3 tube, just need to build the rest. Maybe I can pick up some bubble detectors.