How to hookup a rate meter?

[Steven Sesselmann]

Hi Guys,

Could any of you help me out with a suggestion on how to hook up a simple rate meter to count the clicks from an old Victoreen neutron counter. It only has a "phone" output, which seems to output around 7 mv with each click.

What will I need and how do I wire it?

Any advise appreciated..

Steven

[Richard Hull]

The phone jack is good enough, though it is hard to believe a 7mv click would drive a set of 2K ohm phones. I would stick a buffer audio amp on the jack and then feed it to a digital counter. A single transistor ought to do it.

Probably the cheap and dirty way is to hike down to Radio Crack and buy one of those audio amp/speaker combos in a wall mounted blister pak for about $14.00 and use its output to drive the counter.

Richard Hull

[richnormand]

That will probably work well.
Here is my setup with a 900V PS to drive the GM capacitor coupled to the preamp (that will get replaced by a 50-cent 741 op-amp as soon as I have time). The Ithaco preamp was nice to determine the low and high frequency cutoff and proper amplitude to properly drive the ratemeter. The idea is to ensure that one count is not interpreted as multiple counts by the ratemeter and thus defeating its purpose.

[George Schmermund]

It's probably a good time to start looking for and collecting NIM stuff on eBay. Start with a bin w/power supply and then get a ratemeter, amp, counter/timer, etc. You'll need them all eventually.

[Steven Sesselmann]

Thanks for the advise...

What does NIM stand for?

Steven

[George Schmermund]

Nuclear Instrumentation Module

[Steven Sesselmann]

Thanks,

What does it do?

Steven

[George Schmermund]

Go to www.ortec-online.com. Check products. See Modular Electronics. It represents one of the larger tips of the iceberg.

[Tman]

NIM is just a classification, there is no one nim module.
Start with a small nimbin, which is a rack for nim modules. The nimbin has a built in power supply to power the modules.

Each module is normally around 2-1/2" wide by 8' tall, and plugs right in to the bin.

The first units that would probably be of most use would be a: Rate meter (for cpm) , amp , counter/timer (for total counts).

A nim unit is a good thing to have.

In your case, you would hook the phone jack on your unit to the input of the amp. Then from the output of the amp you would either go to the ratemeter to get your neutron rate (cpm). Or the counter to give you your total counts over time.

hope this answers some of your questions.

-Thiago Olson

[Jon Rosenstiel]

In this forum do a search for "nim faq".

Jon Rosenstiel

[Steven Sesselmann]

Thanks guys for clarifying this for me.

For your information "Nimbin" is also a town on the Australian East coast, famous for it's population of alternative lifestyle people. Basically full of pot smoking hippies on government support.

http://www.tropicalnsw.com.au/aaa_site/ ... imbin.html

A rack in which to place NIM modules is probably more useful!

Steven

[richnormand]

This may be what you need. Works quite well for me once you set the proper mic or aux gain.

viewtopic.php?f=13&t=5676#p34120

[Steven Sesselmann]

George,

You are right, the phone output delivers a very weak click in small headphones.

I will check out that software too.

steven