More Questions on Alpha Emitters

["USHINO, TOSH" <ushinot@songs.sce.com>]

     First of all, I would like to thank all those people who responded to 
     my earlier question regarding alpha recoil and dispersion.  You have 
     provide me with valuable information.
     
     I'm looking for a simple, quick and relatively inexpensive method to 
     do alpha spectrum analysis on air filters.  The goal of the analysis 
     is to determine quickly if the detected alpha activity on an air 
     sample filter is due to natural radon daughter products, or if it is 
     due to other isotopes I have to worry about.  Our current method is to 
     evaluate them by alpha/beta ratio, but the ratio is affected by the 
     age of the sample, sampling time and dust-loading on the filter.
     
     I would prefer to use liquid scintillation counter because another 
     dept already has it, but that could involve destruction of the sample 
     (by dissolution of the filter paper), or require other lengthy sample 
     preparation.  I don't know what the the effect of insoluble(?) 
     concrete or other dust is on liquid scitillation counter efficiency 
     and resolution.
     
     I have heard of certain DOE labs using surface barrier detectors 
     directly on filter papers to look for degraded alpha peaks.  I don't 
     know if the peak resolution is good enough to identify isotopes and 
     how or if they account for dust-loading effect on peak degradation.
     
     I have also heard that other DOE labs ar using something that looks 
     like a miniature PERALS liquid scintillation counter in a NIM bin 
     module.
     
     Can anyone tell me what you know (pro and con) of above methods (or 
     others, such as zinc-sulfide screen on filter) that might work for my 
     situation?
     
     Thank you in advance.
     Tosh Ushino
     SONGS
     ushinot@songs.sce.com