Single channel analyzer

[john scint]

hi all,

My name is John and I try to build signal channel analyzer. Espcsially I would like to made instrument to mesure low x-ray energies about 5-10kev.

I have crystal Cs(ti) with PMt tube EMI 9524.

I have negative high voltage power supply -826v , after charge sencitive amplifier which produce an output with 150μS pulse width and the pulse height about 60mv up to 200mv. Also , I build an operational amplifier LM833 which I power it with +/-12v to increase pulses 20 times , it must?

Moreover , I have LM219 and I would like to build window comparator have some one a circuit?

Lust , I upload the noise of circuit and other photos of my board

[Sesselmann]

Hi John,

Thanks for the introduction..

You do not need much gain for sound card spectrometry, instead you need a nice clean pulse of around 100-150 µs with a pulse height of around 150-200 mV from Cs137 (662 keV). It is preferable to run the signal through an RC filter to round off the top of the pulse.

The sound card Line-In port should have a range of -+1.4 Volts.

Why are you running your PMT with negative voltage, is this the recommended bias?

Normal PMT bias is positive to anode and ground to the photocathode.

Steven

[john scint]

Hi Steven,

thank for your quick reply,

I run PMT with negative power supply because I started before years with one other instrument "DT590 scintillation probe - PDR 56F radiac set" and then building some other like this one ... I shop negative power supply and I start stady from this instrument.....

I would like to build a handle instrument which it can adjust the energy which I need every time and then with TTL pulses on output I'll count them.

have some one circuit?

[Sesselmann]

John,

I wouldn't build a single channel analyser, I would just use an iPhone and geigerbot to achieve the same thing.

https://youtu.be/CMav0wHTEMQ

Steven

[john scint]

Dear Steven

May you have a circuit?

[Sesselmann]

No, haven't made one of those, but Google it and something should come up.

Steven

[john scint]

Also, May you know if and how can I know the energy of every element on kev which instrument scintillation probe detect???

[miree]

Hello John

This website might be useful: http://www.nndc.bnl.gov/chart/chartNuc.jsp You can click on any isotop and get a list of the decay radiation (appears on the bottom of the page after selecting a radioactive isotope). The page has also a link to a gamma finder (click on "Levels and Gammas" on the bottom right of the page) where you can search for isotopes with given decay energy.

Michael

[john scint]

Thank Michael ,

Very useful site.
But the first think on my homemade instrument are that, how can I know the level of voltage (mv per element) haves every element which detect my instrument???
I would like instrument detect only one element after calibration (single channel analyser)

How can I do that? Someone told me this can do only with one radiation source. I have Am-241 amerisium from smoke detector which it haves two peaks the one higher about 56 Kev

[Peter-1]

hello John,
i show you the response from my system with Am241.
The pulse is :

Peter