TC 950 Bias Supply

[Cai Arcos]

Hi:

I recently acquired a TC950 bias supply, and I've got some questions about it which I hope someone could help me with.

1.- The output connectors seem like BNC but with more attention paid to insulation. Does anyone know the name and where to buy this connector?

2.- Similarly, is it possible to acquire the NIM connectors separately? I don't plan on having many modules and racks are expensive due to shipping, so it would be really great for me if I could buy those connectors.

3.-. The LEDs on the face over mention negative and positive polarity, but the two 5000 output terminals are actually linked together and the ten turn pot goes from 0-50. Is the polarity chosen internally.

And finally, If someone has or know where to find a manual, I would be most grateful.

Thanks:
Cai

[Joe Gayo]

1. SHV (https://www.digikey.com/catalog/en/partgroup/shv/2292)

2. Yes, expensive - AMP 202516-3 (https://www.te.com/usa-en/product-202516-3.html look at page 74 of the catalog for pin information), here is the NIM standard https://www.osti.gov/servlets/purl/7120327 for pinout

Look for a small crate like http://www.wiener-d.com/sc/powered-crat ... -150w.html

3. It's either negative or positive output and the pot is x100

[Cai Arcos]

Joe:

You just solved pretty much all of my questions.

Many thanks!

[Richard Hull]

Once powered up, one of the polarity lights will light. If it is not your correct polarity, remove the covers and you will see a board that can be unplugged and can be turned around and re-plugged-in to reverse the polarity. These are common in bias supplies.

Richard Hull

[Cai Arcos]

Richard:

You are correct! I attach a photo, where the polarity changing plug in can be seen.

The supply seems to work fine (I've tested both polarities up to 1kV, without proper connectors I am comfortable going any higher). I thought I had made a great score for this (about 110 euros including shipping), but seeing how simple the circuit seems to be, not so sure.

In any case, I will try to learn how the circuit works to a satisfying degree and what techniques were used (like the costing and layout) so that I can build one better and cheaper myself.

[Richard Hull]

This NIM supply uses a standard high voltage oscillator type supply where near zero currents are necessary. The precision control and regulation is the real issue. That is usually handled via op-amp feedback loop. I designed my own little 400 volt supply (unregulated and fixed) for my little GM counters around a 555 timer. GM supplies are never critical like PMT supplies are. I later turned the 555 out to pasture and used the timer1 feature on the Arduino, itself, to feed the little HV transformer. I attach a couple of images. of the tiny first supply I used before using the Arduino.

Richard Hull