Finding an Xray sensor to buy

[krixen]

I am looking for VERY small xray sensors. As small as they come, to provide current for a low power circuit I have designed. For now I am just looking for any type of small device that can provide current based on the dosage of xray it is in.

Size is the most important aspect I am looking for, efficiency will come second.

Thank you in advance, this seems very hard to find.

 

[BradtheRad]

Never heard of a sensor specifically for xrays...

But I recall that xrays were discovered when ordinary photographic film was left in a drawer with an xray source. The film became fogged, even though it was inside an opaque envelope.

Therefore it might be possible for a light sensor to pick up xrays, if they are sufficiently strong.

I guess you know that xrays are a severe health hazard if they are sufficiently strong.

Digitized xray equipment (as used for dental and medical) may contain the type of sensor you're looking for.

 

[dick_freebird]

Any PN junction is an X-ray detector, as long as you don't
package it in an infinite high-Z shell.

Useful, that's another matter. You need substantial gain
to get much signal out of nonlethal levels of X-ray or
gamma.

PIN diodes are used at high dose rate beam lines. They
give tens of mV into 50 ohms at gamma dose rates that
will ruin your day and the city you spend it in. If you are
looking for a small outline element and dentist's office
type dose rates, I'd say cut your losses and pick a new
project (or a lithium battery). Getting a detectable signal
is enough of a design task; powering a chip wants some
orders of magnitude more captured power (which will
go as photovolume, dose rate and the Vf in photovoltaic
mode of your junction). Note that you put volume as a
key requirement. That will lead to some tough choices.

A photovoltaic cell will give you current from X-rays.
You can calculate the volume photocurrent from the
Wirth-Rogers approximation if you know the vertical
construction. You can find this in the literature. The
details touch on That Which Must Not Be Named
(depending on application) and I will not go further
into it here.

You should not expect much current and your circuit
draw should be very, very, very low.

 

[Dominik Przyborowski]

**broken link removed** You have a description of one quite well working student project using PIN photodiode and front-end with CSA and 3rd order filter.

In polish version of site are a few plots with noise characteristic for various photodiodes.

 

[betwixt]

Interesting link but it is for an X-Ray sensor.
Krixen seems to be asking for one to provide power for a circuit, something like a PV but using X-Ray wavelengths instead of visible ones.

Brian.

 

[Dominik Przyborowski]

This "x-ray sensor" is a cheap SFH206K photodiode from electronic shop not any special detector.