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Sample analysis

Gamma spectrometry — activity from peak area

Model-based estimate. Use the stated geometry, composition and measurement assumptions; see the tool scope for limitations.

Input

Photopeak counts and detector factors

Background counts under the peak for the SAME live time as the sample. If the background was measured for a different time, scale it to the sample live time first.

Absolute full-energy-peak efficiency for this detector and geometry — take it from your calibration.

Gamma yield p_γ
Optional corrections

Result

Activity at measurement time

117.647 Bq
Uncertainty
± 1.18 Bq (1%)
Net counts
10,000

Formula

A = (N_gross − N_bg) / (ε · p_γ · t_live)
Photopeak activity modelEfficiency is detector- and geometry-specific; take it from your calibration.Self-absorption in the sample and true-coincidence summing are not modeled.

Gamma Spectrometry — Activity from Peak Area

Photopeak activity formula

Gamma spectrometry quantifies radionuclide activity from a gamma spectrum. The calculator derives sample activity from a photopeak area: A = (N_gross − N_bg) / (ε · p_γ · t_live), where N_gross is the peak area, N_bg the background under the peak, ε the absolute full-energy-peak efficiency, p_γ the line yield and t_live the live acquisition time.

Database and calibration

The line yield p_γ is entered manually or taken from the radionuclide database for a selected gamma line (element → radionuclide → line cascade). Efficiency ε is detector- and geometry-specific and comes from calibration. Background subtraction, specific activity (Bq/kg, Bq/g), decay-during-counting correction for short-lived nuclides and an uncertainty estimate (counting statistics plus ε and p_γ errors) are supported.

What is not modeled

Self-absorption in the sample and true-coincidence summing are not modeled. Verify the result against a validated method.

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