Abstract: A radiation detector which registers the radiation absorbed during the Prt Initial Radiation (PIR) phase following the detonation of a battlefield nuclear device is disclosed. The dose and dose rate attributable to gamma rays may be measured when the dose rate is low, and the total dose attributable to neutron and gamma ray radiation can be determined separately when the dose rate is high. Two silicon photodiodes are arranged on opposite sides of a slab of polyethylene to gather protons scattered by the incident neutron flux. A third photodiode is set next to a slab of silicon such that its depleted layer is surrounded by silicon. All three diodes are sensitive to gamma ray radiation. When the dose rate is low, the three diodes gather gamma ray dose information. When the dose rate is high, the two diodes adjacent to the polyethylene register combined neutron and gamma ray dose information while the remaining diode registers predominantly gamma ray dose information.