Abstract: A neutron position detector according to an embodiment includes a tubular enclosure used as a cathode, an anode located at an axial center inside the enclosure, and a gas that includes a 3He gas and an additive gas and is sealed inside the enclosure. The additive gas includes nitrogen as a quenching gas, and argon as a gas that reduces the ranges of reaction products as neutron and 3He gas.

Abstract: A neutron position detector according to an embodiment includes a tubular enclosure used as a cathode, an anode located at an axial center inside the enclosure, and a gas that includes a 3He gas and an additive gas and is sealed inside the enclosure. The additive gas includes nitrogen as a quenching gas, and argon as a gas that reduces the ranges of reaction products as neutron and 3He gas.

Abstract: According to one embodiment, a neutron position detector includes a gas including a 3He gas and an additive gas. The gas has a gas composition being set so that a total of ranges of a proton and a tritium in the gas is 2.0 to 2.7 mm. The partial pressures are in an extent surrounded by a first gas composition point of the 3He gas of 5 atm and the additive gas of 1.6 atm, a second gas composition point of the 3He gas of 5 atm and the additive gas of 2.3 atm, a third gas composition point of the 3He gas of 20 atm and the additive gas of 0.6 atm, and a fourth gas composition point of the 3He gas of 20 atm and the additive gas of 1.3 atm.

Abstract: According to one embodiment, a neutron position detector includes a gas including a 3He gas and an additive gas. The gas has a gas composition being set so that a total of ranges of a proton and a tritium in the gas is 2.0 to 2.7 mm. The partial pressures are in an extent surrounded by a first gas composition point of the 3He gas of 5 atm and the additive gas of 1.6 atm, a second gas composition point of the 3He gas of 5 atm and the additive gas of 2.3 atm, a third gas composition point of the 3He gas of 20 atm and the additive gas of 0.6 atm, and a fourth gas composition point of the 3He gas of 20 atm and the additive gas of 1.3 atm.

Abstract: The gas filled in an envelope contains nitrogen and hydrogen. The nitrogen used as a supplementary gas is not polymerized even when radiation is applied to it, and serves to achieve higher resolution than in the case where carbon dioxide is used as the supplementary gas. The hydrogen can reduce the change of gas gain.

Abstract: According to an aspect of the invention, a radiation spectrum measuring system for measuring a radiation spectrum by using a radiation detection element includes, a radiation spectrum measuring unit for measuring a radiation spectrum by obtaining a pulse signal output from the radiation detection element as data, and a rise time detection unit which detects a rise time of the pulse signal, compares the detected rise time with a preset value, and causes the radiation spectrum measuring unit to exclude from data a pulse signal with a rise time longer than the preset value.