Methods and Apparatus for the Detection of Radioactive Materials

A method for investigating a volume of material for radioactive material potentially associated therewith, the method comprising:

• providing an investigation location;
• providing a first detector, the interaction of cosmic rays and/or one or more types of particle generated by cosmic rays with the first detector causing the first detector to generate first signals;
• providing a second detector, the interaction of one or more types of emission from radioactive material with the second detector causing the second detector to generate second signals;
• providing a volume of material at the investigation location;
• detecting a first signal from the first detector caused by the interaction of cosmic rays and/or one or more types of particle generated by cosmic rays with the first detector, starting a first measurement period at a first time relative to the first signal;
• detecting first signals from the first detector and/or second signals from the second detector during the first measurement period;
• starting a second measurement period at a second time;
• detecting first signals from the first detector and/or second signals from the second detector during the second measurement period;
• processing the signals detected during the first measurement period and the second measurement period to obtain their ratio, the value of the ratio indicating a possibility, wherein the possibility is one or more of the following possibilities:
• a) the presence of radioactive material associated with the volume of material;
• or
• b) the absence of radioactive material associated with the volume of material;
• or
• c) uncertainty as to whether there is radioactive material associated with the volume of material;
• or
• d) the presence of high atomic number material associated with the volume of material.

Apparatus for investigating a volume of material for of interest material potentially associated therewith, the apparatus comprising:

• an investigation location;
• a first detector, the first detector providing first signals;
• a second detector, the second detector providing second signals;
• electronics and/or computer software for handling a first signal from the first detector, electronics and/or computer software for starting a first measurement period;
• electronics and/or computer software for detecting first signals from the first detector and/or second signals from the second detector during the first measurement period;
• electronic and/or computer software for starting a second measurement period at a second time;
• electronics and/or computer software for detecting first signals from the first detector and/or second signals from the second detector during the second measurement period;
• one or more processors for the signals detected during the first measurement period and the second measurement period to give a characteristic value, the value indicating one or more of the possible combinations of radioactive material and the volume of material and/or high atomic number material and the volume of material.

Apparatus for investigating a volume of material for radioactive material potentially associated therewith, the apparatus comprising:

• an investigation location, at which, in use, a volume of material is provided;
• a first detector, the interaction of cosmic rays and/or one or more types of particle generated by cosmic rays with the first detector causing the first detector to generate first signals;
• a second detector, the interaction of one or more types of emission from radioactive material with the second detector causing the second detector to generate second signals;
• electronics and/or computer software for handling a first signal from the first detector caused by the interaction of cosmic rays and/or one or more types of particle generated by cosmic rays with the first detector, electronics and/or computer software for starting a first measurement period at a first time relative to the first signal;
• electronics and/or computer software for detecting first signals from the first detector and/or second signals from the second detector during the first measurement period;
• electronic and/or computer software for starting a second measurement period at a second time;
• electronics and/or computer software for detecting first signals from the first detector and/or second signals from the second detector during the second measurement period;
• one or more processors for the signals detected during the first measurement period and the second measurement period to obtain their ratio, the value of the ratio indicating a possibility, wherein the possibility is one or more of the following possibilities:
• a) the presence of radioactive material associated with the volume of material;
• or
• b) the absence of radioactive material associated with the volume of material;
• or
• c) uncertainty as to whether there is radioactive material associated with the volume of material;
• or
• d) the presence of high atomic number material associated with the volume of material.