Patent Number: 048572594
Section: claims

1. A neutron dosimeter comprising: (a) a first layer, made of a fissile material, for producing energetic ions in response to neutron radiation; and  (b) a second layer positioned to receive the energetic ions from said first layer, said second layer comprising a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose;  (c) means, electrically connected to said second layer, for indicating the conductivity of said material.  (a) a first layer, made of a fissile material, for producing energetic ions in response to neutron radiation; and  (b) a second layer positioned to receive the energetic ions from said first layer, said second layer comprising and organic polymer material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose;  wherein said organic polymer is from the group consisting of PPS, PTCDA, NTCDA, NiPc, and Kapton H.  (a) generating in said first layer energetic ions in proportion to a neutron flux;  (b) irradiating in said second layer a material, the electrical conductivity of which permanently varies as a function of its cumulative ion radiation dose of said energetic ions; and  (c) measuring an electrical conductivity change in said material induced by said cumulative ion radiation dose.  (a) means for generating ions in proportion to a neutron fluence to be measured; and  (b) means, disposed adjacent and opposite to said generating means, comprising a material for permanently changing electrical conductivity as a function of cumulative ion radiation dose;  (c) means, electrically connected to said means for permanently changing electrical conductivity, for indicating the conductivity of said material.  (a) a reactor core;  (b) a thermal shield surrounding said reactor core;  (c) a pressure vessel surrounding said thermal shield;  (d) a neutron dosimeter positioned outside of said thermal shield, said neutron dosimeter comprising a layer of fissile material and a second layer made of a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose; and  (e) means, outside said pressure vessel and electrically connected to said layer of second material, for measuring electrical conductivity of said layer of second material. 2. A neutron dosimeter as claimed in claim 1 wherein said second material comprises an organic polymer. 3. A neutron dosimeter comprising: 4. A neutron dosimeter as claimed in claim 1 wherein said fissile material is from the group consisting of .sup.235 U, .sup.239 Pu, .sup.238 U, and .sup.237 Np. 5. A neutron dosimeter as claimed in claim 1 further comprising an electrically insulating layer between said first and second layers. 6. A neutron dosimeter as claimed in claim 1 wherein said fissile material comprises an electrically insulating ceramic material. 7. A method of measuring neutron fluence using a dosimeter having first and second layers comprising the steps of: 8. A method as claimed in claim 7 wherein said generating step further comprises irradiating a fissile material with said neutron flux. 9. A neutron dosimeter comprising: 10. A nuclear reactor comprising: