Fusor Forums

I may have an opportunity to buy one of these neutron detectors. Does anyone have any experience with them or comments? Suggested value based on condition?

Chris,

I've been working in the Nuclear Industry for over 20 years, and the PNR-4 is the old standby for neutron detection. Used to use one everytime I went into the Containment Building - until we got some new compact, liteweight instrument called the REM500. I, myself, have my eyes on a SNOOPY (Navy Neutron Detector) that has been lieing around here for the past 10 years.......replaced the batteries, and it works fine. I might grab one of the PNR-4s also, if I can get one out - they all have a small amount of fixed contamination on them - but that won't be much of a problem. If you do buy one, and need some parts, letme know, we have a few broken ones around here.

Gregg

Gregg,

From what I have heard, the REM500 is a great instrument. I also heard that us common folk could never get one because it contains around a half a micro Curie of Cm 242 which requires a source license. Do you know if that is true and if the REM500 does have a built in neutron source and how is it shielded to make a measurement without counting the source.

Yes, the REM500 is lightyears ahead of the PNR-4. Its small, compact, and lightweight. It is, however, slower in responding to neutron radiation. It updates its digital display every 10 seconds, which gives you a slight delay, but it doesn't cause much of a problem - just takes a little getting used to. Its alot easier to carry when climbing up ladders, than the PNR-4! The only thing I don't like about it, is that the display light only stays on about 10 seconds, then goes out - you have to keep pressing the button. Most of the time when I make an entry into the Containment Building, half of the lightbulbs are out.

As far as the source, the ones we have, have a 1 uCi CM-244 source in them. The licencable quantity of CM-244 is .001 uCi, therefore, even I can't take it home (that's why I've snagged one of the older neutron meters - and I don't have any ladders to climb at home!

I couldn't find a tech manual on it, (I think its in training - we have 4 of these, and only 1 tech manual?), but I think the source is located just outside the detector in a small 1"x2" box. It is used, not to source check the instrument, but to see if the electronics are functioning properly. During the check, a small door opens up to let the detector see the source. We also source check ours with an AM-241 source. I'll try and get my hands on the tech manual if you're still interested.

Gregg

I have 3 PNR-4s and no tech manual. If it could be xerox'd I would be more than willing to pay to have a copy.

Richard Hull

We have a few Tech Manuals at work. I'm working this weekend, and if its slow, I'll see if I can't put one into pdf format and post it here. Also, I'm trying to get a copy (also pdf format) for the Snoopy (NP-2 or AN/PDR-70) from the company. If I get that, I'll post it, also. Mine has a problem with the High Voltage board. We did have 3 others, but they got thrown away about a year or two ago (I must have been on vacation at the time...)

Very interesting. I have a Tracerlabs "Snoopy" that I have been meaning to restore for some time. Right now, it is lacking the battery holder, so I need to add that and go from there. I got a manual that includes schematics from NRC, but I don't know if the circuitry is the same. I'd welcome an older manual.

OK, I uploaded a copy of the PNR-4 tech manual. Its in the files section. I had to scan each page, then convert over to .pdf format, but I did not have the ability to combine all the pages. You would think that if you worked at a multi-million dollar Nuclear Plant, that they could afford the whole Adobe Acrobat program (and not just the reader). Anyway, I zipped all the pages together, so hope that helps.

Richard, I'd appreciate a copy of your "Snoopy" manual (if possible). Mine is a NRC.