Gamma Spectrometry Forum

Hi

Since my first tests and tryouts where successfull (see my "My first spectrum" topic), i want to share my detector with you. Maybe someone is interested in seeing it ;)

I liked the circuit of the theremino, but I'm more a fan of a "one-case-item", so not a circuit where you have to add a soundcard. So i constructed my own version of it.

Basically i copied the HV-Signal-Detection from the theremino circuit. For the Supply i used a ISEG Power supply which was sitting in a shelf for a few years. It can go up to 4kV, but i limited the way to around 1500V, so i can not accidentially set the voltage to high.

For bringing the signal to the computer, i used a PCM2912 Integrated Circuit from Texas Instruments. This is basically a "USB-Soundcard" as a electric component. The Part does not need a special driver and installs automatically under windows. So i can directly interface my detector driver by USB, and do not have to use a Audio-Wire and Soundcard.

The detector driver runs by 12V Wall-Wart.
I made a relatively compact pcb that will fit into an aluminium case which i have ordered, but its not arrived yet :/.

Attached is a image of the finishied pcb and the schematic.

Jonathan,

Thanks for posting, it looks like a neat job, and I look forward to see how it performs. Building the USB audio codec into the driver has been on my list of things to do. This is going to be more relevant in the future as many of the newer laptops have dropped the line in port in favour of a headset port.

Also interested to see how the ISEG HV unit performs on drift and ripple.

Steven

Here on page 3 there is an english datasheet:
http://iseg-hv.com/files/media/BPx_4Wges-RoHS.pdf

I use the +4000V one.
Since i salvaged this unit i do not know its condition or age, nor the new price. The basic results can be seen in my topic in "spectrum" category.

Hi Jonathan,

Nice pcb you made great job!
Iseg make perfect hv units we use it often price is around 200,- to 300,- depending on model
Luuk

luuk wrote: Iseg make perfect hv units we use it often price is around 200,- to 300,- depending on model
Luuk

Wow.... good that i have salvaged this one :)