Application of HIDEX LSC in Mobile Nuclear Laboratory for Rapid Sample Screening Nadereh St-Amant, Sonia Johnson, Kurt Ungar 55th Radiobioassay & Radiochemical Measurements Conference San Antonio, Texas October 26-30/2009 Radiation Protection Bureau Health Canada Canadian Radiological Monitoring Network •Founded in 1959, our ISO 9001-2008 certified group manages 26 environmental stations: •Air sampling •precipitation, and •TLD & OSL •Several reactor sites monitoring stations (ON, QC, and N.B.) •Additional sampling of tritium cells to monitor releases of tritium in atmospheric water vapour Filter Station and Lab Operations Total : 2694 samples in FY 07-08 •1664 air filters •290 precipitation •240 water samples •176 atmospheric water vapour (H-3) •140 TLDs •162 total diet study and milk samples •22 intercomparison and 20 emergency exercise samples  Special projects: Canadian Lab Network Direct ALPHA Field Spectrometry for Forensic samples Nuclear Forensics Intercomparison Programs and Emergency Exercises  One of 16 Radionuclide Labs certified by CTBT  4-6 monthly network samples  Yearly CTBT proficiency test  Annual Federal and Provincial Emergency exercises  2 MAPEP ICPs per year:  air filters, water, soil  Gamma, Sr-90, H-3, Gross alpha/beta  ICP-MS  Yearly IAEA proficiency test:  water, spinach, soil/Moss, Phosphogypsum  NRIP/NIST 8 hr emergency ICP:  air filter, water, urine, soil  FERN/FDA ICP  Po-210/water One of Health Canada’s Mobile Labs How do we achieve this? Laboratory Operations: •4 Gamma analysts with auto samplers (500 samples/day for 6 hour counting time) •CTBT certified laboratory (high efficiency Ge detector) •3 low background LSCs, 2 Hidex LSCs, and Gas Proportional counter •Alpha analyst and high resolution ICP/MS On-Line Separations and Detection of Actinides Advantages:  Increase sample throughput  Small volume needed for urine sample (<10 mL)  Multiple actinides can be measured on one sample (Am/Pu/U/Th)  Resolution of Pu‐239 and Pu‐240 HIDEX LSC, a potential addition to a MNL Features:  HC purchased two in May 2008, upgraded in May 2009 with new re-designed alpha/beta separation module, the cooling unit, and upgraded software  Has an automatic sample changer  Small footprint, portable  Weighs less than 100 kg  Alpha/beta separation with 2 MCA  Quench correction with TDCR Method Triple Double Coincidence Ratio Ct: triple coincidence counts Cd: double coincidence counts ratio of triple to double (all) coincidence is ≈ efficiency for a pure beta emitter Efficiency = k * TDCR K≈ 1 (±15%) Separation Setup Using a Mixed Standard Alpha/beta separation is achieved on the basis of the pulse length index (PLI) Equipped with 2 MCAs, long alpha pulses are measured in the alpha channel and the shorter beta pulses in the beta channel A pure beta and a pure alpha standard is used to establish the optimum PLI limit where counts above the limit are classified as alpha, and counts below the limit as beta Separation of a recent intercomparison Sample •Alpha/Beta separation is seen in a 2 dimensional graph with the x‐axis as channel or energy, the y‐axis as pulse length, and the z‐ axis as intensity • The horizontal line is the pulse length index PLI, which discriminates alpha and beta pulses GPC Hidex MDC (Bq/L) MDC (Bq/L) Gross alpha 0.07 0.1 Gross beta 0.1 0.3 Background alpha 0 cpm; efficiency=100% Background beta ≤ 20 cpm; efficiency>90% Alpha and Beta ROIs Beta I n t e n s i t y Channel Gross alpha activity = 0.92 Bq/L Channel Gross beta activity = 7.2 Bq/L Likely due to Sr-90 and Y-90 The LSC result is in good agreement (99%) with that of the GPC. Sr-90 Measurements Sr-90 Expected Activity (Bq/L) GPC (Bq/L) Hidex (Bq/L) Standard #1 (15) Standard #2 (20) 14.43 23.10 14.01 20.39 Standard #3 (50) 44.35 47.58 Standard #4 (50) Standard #5 (50) 61.97 54.53 56.72 52.45 Intercomparison (8.90) 9.68 9.47 Intercomparison (10.80) 11.34 11.61  TDCR (Efficiency) ≥ 0.85 H-3 Measurements Channel MDC = 10 Bq/L Background = 11 cpm Expected dpm Measured dpm % Difference 159 155 3 405 414 2 952 942 1 1512 1558 3 Spiked urine sample Urine sample spiked with Am-241 Blank and sample counted for one hour 0% difference between measured and spiked activity Summary  Hidex is potentially a useful tool for radioactivity screening of samples in a mobile laboratory setting  low-level counting can be achieved without the use of the external standards through automatic TDCR method and alpha/beta separation is possible without the prior knowledge of pulse length  Preliminary results for H-3, Sr-90, gross alpha/beta in water and Am-241 in urine samples are very promising  Future work is to develop protocols for various alpha and beta emitters in different matrices and develop SOPs for emergency response/exercise THANK YOU Acknowledgments: • Ville Haaslahti from Hidex • Jessica Vanderveen for sample preparation