Beta Spectrometry

Performed using either plastic or liquid scintillation spectrometry. A number of analysis options are available depending on the nature of the sample and the level of sophistication required. These options are listed below as methods A, B, and C, but note the differences for solids and liquids, and the additional costs for digestion and chemical separations. For solids, a minimum sample size of 5g is required. For water and aqueous solutions, a minimum volume of 500ml is required.

A) High Energy Beta (150keV - 2.5MeV) Analysis on Plastic Scintillator

Typical radionuclides include 144Ce and 90Sr.

Solids:

• A thin (5 mg/cm2) sample is prepared for plastic scintillation counting. Assuming a single beta emitter, detection limits of 1 Bq/g are typical. Clients are cautioned that activity may be underestimated due to self-absorption in the sample. As an option, solid samples can be acid digested in order to prepare a thin source to alleviate absorption and reduce minimum detectable activities to, typically, 0.1 Bq/g.

Liquids:

• 500ml aliquots are evaporated and then counted using the plastic scintillator. Detection limits of 0.2 Bq/L are typical.

B) Low Energy Beta Analysis (<200keV) on Liquid Scintillator

A maximum of three radionuclides can be determined simultaneously for any given sample. If more than three beta emitters are present, radiochemical separation techniques must be employed. Additional charges are made for radiochemical separations (see section D).

Solids:

• A sample is acid digested to dissolve the beta emitter(s). The acidic medium is then used to prepare a sample for counting. For 63Ni, a detection limit of 10 Bq/g is typical. Volatile species, such as 3H2O, H36Cl, and 14CO2 are also collected and analyzed simultaneously. Detection limits of 20 Bq/g are achievable for 36Cl and 14C. Tritium has a 30 Bq/g detection limit. Isotope separation is required if these limits are to be lowered to typical values of 1 Bq/g.

Liquids:

• Preconcentration techniques are used to reduce typical minimum detection limits to .2 Bq/L.

C) Tritium Analysis

Aliquots from liquid samples are counted using liquid scintillator spectrometry. In the absence of other emitters, a detection limit of 75 Bq/L can be obtained.

D) Radiochemical Separation

To obtain the most reliable estimate of activity, radiochemical separation is required if more than one beta emitter is present in the sample. Samples are digested in acid and each radioisotope is chemically isolated.


Please contact BTI at services@bubbletech.ca for detailed pricing information.