An Ideal NIM bin.

[Richard Hull]

Revisiting the NIM bin issue, I was assembling a NIM bin for
sale to a friend and he asked what the ideal NIM bin might contain in the way of modules. Nice question!....After musing over it, here is my answer to myself.

If you are measuring a specific thing and nothing else, your needs might be minimal. (3 modules) If however, you are looking at long haul, multipurpose diagnostics and assembly of a number of full blown nuclear instruments with your NIM system,(which is what I do), then here is a short list of what I think are gotta' haves.

1. Power supply high voltage (0-2kv) tightly regulated to .05% or better. The most expensive of all the modules you are likely to encounter.

2. Power supply of the bias type, ultra HV (like 0-5kv) loose regulation.

3. Scaler-timer for counting and timing operations.

4. Ratemeter complements the scaler above via time integration and analog readout.

5. SCA - Single Channel Amplifier A must have item. Get a very good one! A good one will be expensive.

6. Pulse amp and variable gate delay module. Sets up timing chains and alters pulses, if needed.

7. Precision reference pulser A must have for diagnostics and instrument assembly/testing/analysis. Also a boon to normal nuclear instrument repair and calibration.

8. Discriminator/biased amplifier, optional, weird item, but when you need it, there is no substitute.

This cream de la cream of NIM modules and the bin could set you back quite a bundle ($2000+) at normal warranted surplus prices. you might get it all for under $1000 if you are lucky on E-bay. (actually receive working stuff)

In reality, I have all these modules plus many more on my shelves and assemble as needed. The above however are usually permenant residents of my main bin. If I want to assemble a specialized instrument, I will normally grab another unpopulated bin and build the instrument up with off the shelf modules I have on hand, rather than mess with my super bin.

Needless to say, if you don't understand the basics of nuclear instrumentation then having all this stuff would be like a big city executive with an extensive collection of fine weapons who has never fired a weapon in his life. (All the trappings with none of the skills.)

Still, if the wallet allows and a future with the stuff is imagined, a slow and intelligent acquistion program might prove beneficial, in the long term. The knowledge can be acquired on the fly and under the "hands on imperative".

I am considering producing a training video on the NIM system with the actual assembly and use of a few simple instruments illustrated after a precursor of a module tutorial. It is a matter of putting my foot in the path though.

Richard Hull

[r_c_edgar]

I think a NIM training video would be an excellent idea. I've just started really getting serious about obtaining a good in-depth understanding of the nuclear instrumentation I'm going to need, and I have no doubt that such a video would be invaluable.

Do you think you could put a dollar value on some of those parts individually? The kind of prices one could expect from good, reliable surplus sources like you or Don Orie (http://www.oetech.com) , perhaps. I'm thinking in particular the SCA, biasing hv supply, and scalar-timer (which I believe are the absolute basics you'd need for a neutron counter, along with maybe a pre-amp module?)

--Ryan Edgar

[Richard Hull]

In answer to Ryan's query.........

I actually bought my bias supply and ultra stable supply from Don Orie at OE tech and he gave me a slight break on the both. They were $675.00 total

A good SCA of real worth and in excellent shape might run $150-200. A good used one on E-bay of moderate Quality might be had for $75-125. Sclaer timers are a real bug-a-boo! They come in a million flavors and age groups. I have about 6 of 'em and they all work great. The oldest is a Victoreen- Tullmore (circa 1960s) and the newest an ortec 871 (Circa 90's).
They range from a low of about $70 for an E-bay mystery device sold as is to a high for an 871 in warranted condition for about $300 with a vast range in between.

So there you have it. If you can repair electronics, know a bit about instrumentation and digital logic then E-bay can save you money, but not necessarily time or frustration.

That wonderful old victoreen takes up 4 Nim slots and is composed of 6 decades of binary coded decimal lamps per decade. I will throw a shot of it up on Images du jour for a limited time.

Richard Hull

[Tom Dressel]

This weekent I went to my brother's lake cabin in northern Minnesota, and on the way there I stopped off in Brainard for their hamfest. Not much stuff that I could use, but I ran into Al Dieken, the former 3M employee, that I met in in June at the Eau Clare hamfest. He is sort of the "Don Orie of Minnesota" he is a consultant and sels surplus test equipment. He has a bunch of regulated high voltage power supplies, a five foot tall stack of NIM components in his garage (most if not all of the components mentioned on Richard's post),and several NIM crates that he will sell for $100.00 each. I THINK that is a fare price for a working NIM bin.

He lives in the Mpls. metro area, I hope to get to his place this week, and I will use Richard's wish list as a guide to what I need.

[guest]

Humm ... I have a question about Item #8 on your list for the ideal nim bin. Can you elaborate on the uses for this nim module? Another list that would be helpful to neofites would be a list of the test equipment needed to maintain and test a nim bin.
I would be interested in a Nim Bin for Dummies video.

Larry Leins
Physics Teacher

[Richard Hull]

The discriminated biased amp is a bit of an odd fish, but is handy mainly for semiconductor detectors (PIPS, SBDs, etc.)
The amp may or may not have an internal bias supply, but instead a BNC jack on the rear for a variable DC input voltage.

Such amps are designed to distribute a variable voltage to the semiconductor detector and even preamp power via a rear 9 pin plug. It receives the raw preamp signal out and lets you not only set a discrimnator level to determine pulse detection level, but sometimes even lets you establish a DC bias or offset output level for signal out. This can also be used to adjust to zero or null any DC offset out of the preceeding DC preamp. Versatile, but specialized.

The NIM for Dummies video is still a pipe dream and like all of my introductory videos will be very basic and not make the user an expert or show fancy extended or advanced uses, but, instead, how to assemble common instrumentation, care and maintain the units, etc.

If one is serious about NIM and advanced nuclear instrumentation work, only a good storage scope and good DVM would be needed to maintain and adjust systems.

Richard Hull

[Tom Dressel]

Now that I have one, (Tektronix 2230), I can second Richard's advice about getting a digital storage scope, even an old one like mine. I haven't finished reading the manual yet, but being able to capture the fast pulses, has really helped me learn and understand how the various NIM components work togather.

Before getting the scope, I couldn't understand why putting the Cs127 source up aganst the scintillator increased the CPM but not the averaged PMT preamp output pulse height!! When I first got the DSO running, I still saw no increase in the average pulse height. I didn't realize that I had to increase the SCA baseline to SEE the average of the larger pulses.

I am sure that the DSO will provide many hours of play time.

Tom Dressel

[Richard Hull]

Yes. It is like having a time machine window that allows you to capture, see, analize and study the blazingly fast world of atomic events, or at least the electronic reactions secondary to those events. The window freezes a micro second of time that occured over 20 million of the event intervals in the past which becomes a more distant and receding event as you look at the screen. The analysis lets you prepare for the future, wisely.

Every such tool added to your inventory not only furthers and assists your effort, but your education as well.

Richard Hull

[LehighUBoy]

Was the training video for NIM systems ever produced? I've acquired a few modules (3106D, 2022, 8075, & 8222) ... and I'm interested in learning what combination of units are needed for various measurements.

Thanks, Garrett

[Richard Hull]

That video is on hold for a while. I just haven't had the time since my work has been a zoo for over a year. Sorry 'bout that.

I'll make a formal announcement here in the radiation forum when it is done.

Richard Hull

[LehighUBoy]

Would you consider posting a FAQ for basic setups?

Thanks, Garrett

[3l]

Hi Garrett::

He already did.
it this post:
2001-11-09 11:50 FAQ - NIM - SPECS - HISTORY ongoing and updated (Richard Hull) [Latest: ] (3)


Happy fusoring!
Larry Leins
Fusor Tech