Multifaceted radiation detection and classification system

One or more computing systems comprising:

• one or more computer-readable storage mediums for storing computer-executable instructions, execution of which causes the one or more computing systems to:
• cause a radiation source detector to engage in long-term historical local background radiation measurements;
• cause the radiation source detector to capture a source signature of a measurement of a source of radiation;
• access, by a radiation source detector, the source signature of the measurement of the source of radiation and an estimated background, the estimated background based on historical local background radiation measurements;
• generate a first hypothesis based on the estimated background and an estimated background rate;
• generate a second hypothesis based on the estimated background, the estimated background rate, and the source signature;
• generate a first likelihood for the first hypothesis given a Poisson distribution;
• generate a second likelihood for the second hypothesis given the Poisson distribution;
• generate a projection vector based on the first likelihood and the second likelihood;
• access a measurement of a physical quantity of radiation via a radiation detector;
• and
• generate, by the radiation source detector, a metric based on the measurement, the projection vector, and the estimate background rate;
• and
• one or more processors to execute the computer-executable instructions stored in the one or more computer-readable storage mediums.

A method performed by a computing system for generating a metric for indicating presence of a measurement of a source of radiation in measurements of radiation collected in sequence, the method comprising:

• causing a radiation source detector to engage in long-term historical local background radiation measurements;
• causing the radiation source detector to capture a source signature of the source of radiation;
• constructing hypotheses represented by the following equations:
• H
• 0
• =
• B
• s
• ⁢
• B
• r
• ⁢
• Δ
• ⁢
• t
• H
• 1
• =
• B
• s
• ⁢
• B
• r
• ⁢
• Δ
• ⁢
• t
• +
• S
• s
• ⁢
• k
• ⁢
• B
• r
• ⁢
• Δ
• ⁢
• t
• where H0 and H1 are the hypotheses, Bs represents a background shape, Ss represents a source signature shape, Br represents a background rate estimate, Δt represents change time period, and each shape is a histogram with a total count of 1, wherein the background rate estimate is based on the historical local background radiation measurements of physical quantities of radiation in the predetermined location;
• calculating a likelihood of each measurement given Poisson statistics as represented by the following equation:
• P
• ⁡
• (
• X
• ❘
• H
• )
• =
• ∏
• i
• ⁢
• exp
• ⁡
• (
• -
• h
• i
• )
• ⁢
• h
• i
• x
• i
• x
• i
• !
• where hi represents the i-th element of the hypothesis;
• generating a ratio of the hypotheses as represent by the following equation:
• LRT
• ⁡
• (
• X
• )
• =
• log
• ⁡
• (
• 1
• +
• k
• B
• r
• ⁢
• Δ
• ⁢
• t
• ⁢
• S
• s
• B
• s
• )
• t
• ⁢
• X
• -
• k
• B
• r
• ⁢
• Δ
• ⁢
• t
• =
• T
• t
• ⁢
• X
• +
• M
• .
• generating the metric by as represented by the following equation:
• DM
• =
• (
• T
• t
• ⁢
• X
• +
• κ
• ⁢
• B
• r
• ⁢
• Δ
• ⁢
• t
• )
• vB
• r
• ⁢
• Δ
• ⁢
• t
• where DM represents the metric and K represents a bias term for any difference in the estimated total count in the background and an expected background total count in the background.

A method performed by a computing system for adjusting measurement counts of measurements of a physical quantity of radiation via a radiation detector to account for temporary changes in the measurements, the method comprising:

• causing a radiation source detector to engage in long-term historical local background radiation measurements;
• causing the radiation source detector to capture a source signature of the measurement of the source;
• accessing a plurality of measurements of the physical quantity of radiation;
• for each of the measurements, generating a measurement count of that measurement;
• generating an upper average measurement count that is an average of the measurement counts higher than a threshold count;
• calculating an expected offset for a probabilistic distribution based on the upper average measurement count and the measurement counts higher than the threshold;
• and
• for each measurement, subtracting the expected offset from the measurement count for that measurement.

One or more computing system for adjusting measurement counts of measurements to account for temporary changes in the measurements of a physical quantity of radiation via a radiation detector, the one or more computing system comprising:

• one or more computer-readable storage mediums for storing computer-executable instructions, execution of which causes the one or more computing systems to:
• causing a radiation source detector to engage in long-term historical local background radiation measurements;
• causing the radiation source detector to capture a source signature of the measurement of the source;
• for each measurement of a plurality of measurements of a physical quantity of radiation via a radiation detector, generate a measurement count of that measurement;
• generate an upper average measurement count that is an average of the measurement counts higher than a threshold count;
• calculate an expected offset for a probabilistic distribution based on the upper average measurement count and the measurement counts higher than the threshold;
• and
• for each measurement, subtract the expected offset from the measurement count for that measurement;
• and
• one or more processors to execute the computer-executable instructions stored in the one or more computer-readable storage mediums.