(but I don't know wheter this foil also acts as a szintillatior). Mylar is not scintillating, not as far as I know. It�s being used as very thin and therefore good window substance of ordinary counting tube.
BTW: The east German army had a -in that time, 1980�s , very sophisticated radiation monitor, bulky piece, 2 kg, water proof aluminum case, fully digital uC (!!!) LED readout etc. But all the literature says about the sensor is "semiconductor sensor". I always thought it�s a photodiode +scintillator but maybe it�s a diode only. IF (!!) this diode was Russian, the typecode could be WRWR-30 or VRVR30 in latin letters. The "-" between letters and number of designation isn�t typically Russian. Why don�t you get yourself some cheap photodiodes from www.reichelt.de or wheresoever and find somebody with a "good" radioactive probe substance, maybe at the next university ? Keep us updated, this sounds like an interesting discussion:-) Jan I would really like to give this > MR> circuit a try before looking for such a special detection diode. > > MR> Further researches about the author braught up the following results: > MR> The article was published in "Electronics Designer's Casebook No.3 for > MR> the period Feb 16, 1978 to Jan 4, 1979". The author doesn't work for the > MR> indicated institute in poland any more, not quite a surprise. So I can't > MR> contact him directly. > > MR> But this tells us that the diodes are at least 25 years old and probably > MR> of eastern europe type (former CCCP I think, but not sure). So if anyone > MR> of the list members has an old data book on the shelf, please take a > MR> look ... > > MR> Today's photodiodes should have a higher performance/sensitivity, so > MR> would a general purpose type (which one?) be ok for a simple test of the > MR> circuit? > > MR> Best Regards > MR> Markus > > May I clean up a bit? > Indeed any pn junction is sensitive to ionizing radiation, independent > of the type of radiation. alpha, beta and gamma do all create > electron-hole pairs in the semiconductor material, while loosing some > energy themselves. The energy loss per created eletron-hole pair is > about 3x the band gap energy of the material, i.e. 3x 1.2eV in the > case of silicon. If the electron-hole pair is created in or near the > depletion region of the junction, the external field will separate > electrons and holes and accelerate them towards the oppositely charged > electrodes. These carriers appear then as an electric current through > the diode. > There are special diodes for these purposes around which have an > extremely wide depletion region by the in-diffusion of lithium into > the semiconductor material - they can even fully stop an alpha > particle in the active region and the full energy of the particle will > be converted. This allows an accurate measurement of the energy of the > incoming alpha particles. A normal pn or even pin diode will only > absorb part of the energy in the sensitive region and can still be > used to detect the presence of radiation. > > For Markus' project _any_ pn or pin diode will do if he can expose the > junction to the incoming radiation. As described in the article a > diode in a metal can with glass window is easiest to use, since you > can remove the front window and replace it by an alpha-transparent > material, such as the mylar foil described in the article - of course > it has to be really light-tight, otherwise you will detect anything > else as well. > > Gamma and X-ray radiation has very little energy loss in most > semiconductor materials, requiring very thick depletion regions to be > detected. Since these are hard/impossible to manufacture and also very > sensitive to thermal noise, scintillator materials are used to convert the > incoming radiation into visible light which is easily absorbed in the > junction. > > Just a rough estimation of the absorption depth in semiconductors: > alpha 1-10um > beta 5-50um > gamma several mm > > Uwe. > > -- > Author: Uwe Zimmermann > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB CHIPDIR-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). > mit freundlichen Gruessen---best regards Frag'Jan Zuerst -----Ask Jan First Jan Philipp Wuesten Elektronik Rodauer Strasse 38 D- 64372 Ober Ramstadt, Germany Phone: +49-6154-575556 Fax : +49-6154-575557 <http://www.die-wuestens.de> (German and English) mail to <[EMAIL PROTECTED]> or <[EMAIL PROTECTED]> -- Author: Jan Wuesten INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
