Re: Track etch on glass

["Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>]

Private:

Franz Schoenhofer

Habicherg. 31/7

A-1160 Vienna, AUSTRIA

Phone: -43 699 11681319

e-mail: franz.schoenhofer@chello.at



Office:

MR Dr. Franz Schoenhofer

Federal Ministry for Agriculture, Forestry, Environment and Water Management

Dep. I/8U, Radiation Protection

Radetzkystr. 2

A-1031 Vienna, AUSTRIA

phone: +43-1-71100-4458

fax: +43-1-7122331

e-mail: franz.schoenhofer@bmu.gv.at



Maybe I misunderstood everything in your posting or I understood nothing at

all. I cannot find out, what you actually want to measure, except that you

mention "glass dosimetry", so it is probably a dose. External dose rates

from gammas? I would be more than surprised, if they could cause tracks in

glass (or in CR-39). Is it thought for measuring high fluxes of some kind of

charged particles? What would create tracks in glass?



Regarding "radon tracks", better "tracks caused by radon daughters":

"Etching" as I know it, refers to treating the CR-39 or similar with basic

solutions or use an electric current to make the tracks visible and not to

etch off a layer! Track etch detectors are still very widely used as a

reliable passive mean to determine the concentration of radon (and sometimes

daughters) in indoor air and is of course used for sensitive measurements

down to very low levels, using an integration time of usually three months.



The only case, in which I know about "glass and radon" is the use of old

glass surfaces (like mirrors or glass covering a photograph), which had been

exposed for years to the radon in the same room, to retrospectively

determine the  radon concentration average over a long time period in houses

to be used in health studies on radon and lung cancer. But then the

principle is, that Pb-210 plates out at the surface and attaches strongly to

it, so that its activity can be measured usually by low-level gas-flow

counters.



Regards,



Franz



-----Ursprüngliche Nachricht-----

Von: Robert J. Gunter <rjgunter@chpconsultants.com>

An: radsafe@list.vanderbilt.edu <radsafe@list.vanderbilt.edu>

Datum: Dienstag, 08. Jänner 2002 19:12

Betreff: Track etch on glass





>Greetings All,

>

>What type of control methodology is used for track etch on glass

>dosimetry.  I assume it is similar to that for CR-39 where there are

>batch controls that account for the variability between batches to the

>point at which you can account for the location on the pane of glass

>from where the detector was taken.  Is this so?

>

>I could see how this would differ in that with using CR-39 for neutrons

>you etch off the outer layer to eliminate the radon tracks.  Are the

>alpha tracks on glass obscured by high backgrounds?   After all, you can

>use CR-39 for radon too, though I am unsure how effective it is at low

>levels.







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