A muon detector includes: a chamber having a maximum cross-sectional dimension of 30 cm or less; a gas sealed inside the chamber ionized by the passage of atmospheric muons to form ions in the chamber; a cathode in the chamber at a first position; an anode in the chamber displaced from the first position, the anode including a mesh of wires; a micropattern gaseous detector arranged between the cathode and the anode and proximate to the anode and configured to receive the ions formed in the chamber between the anode and the cathode and generate electrons in response to each ion sufficient to generate a current in one or more of the mesh wires of the anode; and readout electronics in electrical communication with the anode to detect signals in response to the current generated in the mesh wires.

A radiation dose rate monitor system includes an emitting electrode configured to be impinged by radiation radiation; a collecting electrode configured to form an electrical circuit with said emitting electrode, a current measurement device configured to measure a current through said emitting and collecting electrodes indicative of a dose of said radiation radiation, and a chamber enclosing a gas. Emission of secondary electrons from the emitting electrode provides a majority of the current.

A photoelectric tube includes a housing including a light transmitting portion, an electron emitting portion held by a recess provided in the housing, the electron emitting portion including a concave photoelectric surface facing a light transmitting portion side inside the housing, and an electron capturing portion disposed between the light transmitting portion and the photoelectric surface inside the housing. At least a part of the electron capturing portion is located inside a region on an inside of the photoelectric surface.

A photoelectric tube includes a housing including a light transmitting portion, an electron emitting portion held by a recess provided in the housing, the electron emitting portion including a concave photoelectric surface facing a light transmitting portion side inside the housing, and an electron capturing portion disposed between the light transmitting portion and the photoelectric surface inside the housing. At least a part of the electron capturing portion is located inside a region on an inside of the photoelectric surface.

An asymmetric dual-mode ionization chamber measurement system can include a first high-voltage plate, a second high-voltage plate and a readout plate. The first high-voltage plate can be disposed from the readout plate by a first active volume. The second high-voltage plate can be disposed from the readout plate by a second active volume. A high-voltage potential can be coupled to the first high-voltage plate during a first mode, and to the second high-voltage plate during a second mode. Ion pairs generated by a radiation stream passing through the first active volume during the first mode and the second active volume during the second mode can be measured at the readout plate to determine a radiation rate of the ionizing radiation. The asymmetric dual-mode ionization chamber measurement system can advantageously measure different radiation streams that have significantly different ranges of radiation rates flux.

Various embodiments are described herein for sensors that may be used to measure radiation from radiation generating device. The sensors may use a collector plate electrode with first and second collection regions having shapes that are inversely related with one another to provide ion chambers with varying sample volumes along a substantial portion of the first and second collection regions which provides virtual spatial sensitivity during use.

Various embodiments are described herein for sensors that may be used to measure radiation from radiation generating device. The sensors may use a collector plate electrode with first and second collection regions having shapes that are inversely related with one another to provide ion chambers with varying sample volumes along a substantial portion of the first and second collection regions which provides virtual spatial sensitivity during use.

An apparatus includes an ion chamber and a valve assembly. The ion chamber may include a housing enclosing a gas and one or more electrodes. The valve assembly is coupled to the ion chamber allowing control of replacement of the gas within the housing.

A narrow thermal neutron detector includes a slidably receivable ionization thermal neutron detector module within an overall housing body. An active sheet layer of the ionization thermal neutron detector module can be tensioned across its width. The ionization thermal neutron detector module can include module upper major surface extents and module lower surface extents such that, when installed within the housing body, the module upper major surface extents are in a first spaced apart confronting relationship with housing upper major surface extents to define a first clearance and module lower major surface extents are in a second spaced apart confronting relationship with housing lower major surface extents to define a second clearance to accommodate housing flexing due to ambient pressure change. The housing body can be formed with a single opening for receiving the ionization thermal neutron detection module or with opposing first and second opposing end openings.

A narrow thermal neutron detector includes a slidably receivable ionization thermal neutron detector module within an overall housing body. An active sheet layer of the ionization thermal neutron detector module can be tensioned across its width. The ionization thermal neutron detector module can include module upper major surface extents and module lower surface extents such that, when installed within the housing body, the module upper major surface extents are in a first spaced apart confronting relationship with housing upper major surface extents to define a first clearance and module lower major surface extents are in a second spaced apart confronting relationship with housing lower major surface extents to define a second clearance to accommodate housing flexing due to ambient pressure change. The housing body can be formed with a single opening for receiving the ionization thermal neutron detection module or with opposing first and second opposing end openings.