Price List

A. Tritium measurement

1. Low-level gas proportional counting of water sample. Required sample volume 15 mL; processing quantity is 4 mL. $225.
   
   Counting will be performed to ± 3.5%, one sigma, or ± 3 TU (10 pCi L^-1), whichever is larger. Minimum detectable activity (MDA) is 3 TU (10 pCi L^-1). Special arrangements will have to be made for undersized or chemically contaminated samples. Advanced notice is required for samples suspected to be above 1000 TU (3200 pCi L^-1).

2. Enrichment and low-level counting of ultra-low activity water sample. Required sample quantity 1000 mL. Normal starting volume is 275 mL. $375.
   
   Accuracy and precision will be 0.1 TU (0.3 pCi L^-1) or ± 3.5%, whichever is larger. MDA is 0.1 TU (0.3 pCi L^-1). Special arrangements will have to be made for undersized or chemically contaminated samples. Advanced notice is required for samples suspected to be above 30 TU (100 pCi L^-1).
   
   NOTE: Stated starting volume is needed for obtaining quoted accuracy: a smaller quantity will usually yield less precise results. We will take no more than one third of the furnished amount of water for the first run unless instructed otherwise by submitter.

3. Pre-testing of sample to determine if enrichment is necessary. Required sample volume 1 L. $125.
   
   Direct counting (as in A.1) will be performed for a set period of time to determine if tritium content is low enough to require prior enrichment. Submitter must provide criterion for enrichment beforehand. If sample does not require enrichment, the counting will continue until the criterion under A1 is met and the total cost is the same as above in A.1. If enrichment is required, we have to start from scratch and the cost is sum of A.2 and A.3, i.e. $500.

4. Direct Liquid Scintillation Counting. Required sample volume 50 mL. $75.
   
   Accuracy and precision will be 40 TU (130 pCi L^-1). MDA is 40 TU. Samples will be counted for a minimum of one hour on a Tricarb 2910TR liquid scintillation counter (LSC) with the low level counting

B. Extraction of water from soils

Extraction of water from soil or rock. $125.00

Water will be removed from sections of soil or rock cores (4 inches maximum diameter, 5.5 inches maximum length) with a vacuum distillation processes. Cost for tritium analysis of extracted water can be found in section I.A.

C. Low Tritium “dead water”

Low Tritium “dead water” (< 0.1 TU) $50.00.

This freshwater is collected from an artesian well that is screened at a depth of ~ 100 m below the water table. Based upon hydraulic conductivity this water has not been in contact with the atmosphere for several thousand years and should therefore contain undetectable amounts of tritium. Analysis of this water by the Tritium Laboratory indicates that the tritium levels are below our detection limit (< 0.1 TU). The Tritium Laboratory uses this water for analytical instrument blanks. This water is suitable for use as analytical instrument, field and equipment blanks. The water will be delivered in 1 liter polyethene bottles. Batch analysis available upon request.

D. CFC-11, CFC-12, CFC-113, and SF₆ analysis

CFC-11, CFC-12, CFC-113, and SF₆ analysis. $225.

Water samples are analyzed for CFCs and SF₆ using a custom-built purge-and-trap gas chromatograph with electron capture detection. This method is extremely sensitive and the limit of detection for the CFCs is 0.001 x10^-12 moles per kilogram of water (pmol kg^-1). The limit of detection for SF₆ is even more sensitive at 0.01 x 10^-15 moles per kilogram of water (fmol kg^-1). Precision values for all three CFCs are 2 % or less. SF₆ precision is 5% or less. The accuracy of CFC and SF₆-derived recharge ages from these measurements is 3 years or less.