Evaluation of polymer-coated CsI:Tl as an alpha/beta pulse shape discriminating flow cell
- Nuclear Regulatory Commission, Washington, DC (United States)
- Clemson Univ., SC (United States)
A pulse shape discriminating flow-cell radiation detection system constructed with polymer-coated CsI:Tl was evaluated for simultaneous gross alpha/gross beta quantification. The CsI:Tl scintillator was crushed and sieved to 63--90-{micro}m particle size and encapsulated with Parylene C to slow its dissolution rate. Averaged over the first hour of use, the pulse shape discrimination figure of merit was 1.4, and the detection efficiencies ({+-}1{sigma}) were 64.9 {+-} 5.7%, 52.5 {+-} 4.5%, and 4.5 {+-} 0.2% for {sup 233}U, {sup 90}Sr/{sup 90}Y, and {sup 14}C, respectively. The typical background count rates in the alpha and beta pulse shape window were 0.004 and 0.17 cps, respectively. The resultant minimum detectable activities ({+-}1{sigma}) for a 30-s count time were calculated to be 0.19 {+-} 0.01 Bq, 0.9 {+-} 0.1 Bq, and 11.4 {+-} 0.6 Bq for {sup 233}U, {sup 90}Sr/{sup 90}Y, and {sup 14}C, respectively. Although the 3-{micro}m-thick encapsulation slowed CsI:Tl dissolution, the detection efficiency declined by a factor of two after 4.8 h, while the pulse shape resolution degraded slightly. With an appropriate coating, CsI:Tl is a good candidate for a heterogeneous pulse shape discriminating flow-cell.
- Sponsoring Organization:
- USDOE Morgantown Energy Technology Center, WV (United States)
- DOE Contract Number:
- AR21-95MC32110
- OSTI ID:
- 531499
- Journal Information:
- IEEE Transactions on Nuclear Science, Vol. 44, Issue 4Pt2; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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