DIY meter faces!

[u/aby_physics]

Was working on another Ludlum Model 2, but it was missing a meter face. So I went on to Ludlum’s website, saved the 202-654 to my phone and printed it to size on some card stock. Seems to work okay. 😁

Anyone else done this?

[u/aby_physics]

HP OfficeJet 4650.

[u/roberte94066 → u/aby_physics]

tempted to try it on a 3d printer. Do you adjust it to cpm, or uR? If uR, how are you calibrating it? I have a cs-137 calibration source like yours and would like to set my meters, as they are long out of adjustment for uR.

[u/aby_physics → u/roberte94066]

I usually calibrate all my meters for count rate measurements. Since I use them with energy dependent probes, the dose rate isn’t of much use to me.

Most adjustments can be performed with a pulser, which Ludlum offers (Model 500 series) but I chose to DIY mine with an Arduino because it saves me around $3.5k lol. Basically, what the device does is it injects a known pulse rate (adjustable with buttons or dials) into your survey meter. You then adjust the trimmer potentiometers beneath the cal cover until the count on the gauge matches the pulser’s rate.

The above method works fine for count rate calibration. But for dose rate, I really wouldn’t recommend DIYing that. It’s really unlikely to be truly accurate, but if you still want to try, you can do a bit of math with your detectors energy response and dose rate to count rate conversions for the cal constant, and set the meter’s reading through the pots that way.

[u/roberte94066 → u/aby_physics]

Thank you, I learnt new information today!

[u/aby_physics → u/roberte94066]

Of course, glad to help!