A boron neutron capture therapy system includes a neutron capture therapy device, a photon emission detection device and a treatment bed. The photon emission detection device includes a detecting portion surrounding the periphery of the treatment bed and detecting gamma rays generated after irradiating a boron-containing drug with neutrons; the detecting portion includes a first detecting portion and a second detecting portion moving away from or close to the first detecting portion so that the detecting portion forms a ring with the radius being increased or decreased; and the ring surrounds the treatment bed. The photon emission detection device for use in the boron neutron capture therapy system can change the radius of the ring, surrounding an irradiated object, of the detecting portion according to the actual condition in the boron neutron capture therapy so as to improve the detection precision of the photon emission detection device.

Disclosed is a moderator for moderating neutrons, including a substrate and a surface treatment layer or a dry inert gas layer or a vacuum layer coated on the surface of the substrate, wherein the substrate is prepared from a moderating material by a powder sintering device through a powder sintering process from powders or by compacting powders into a block, and the moderating material includes 40% to 100% by weight of aluminum fluoride; wherein the surface treatment layer is a hydrophobic material; and the surface treatment layer or the dry inert gas layer or the vacuum layer is used for isolating the substrate from the water in the environment in which the substrate is placed. The surface treated moderator can avoid the hygroscopic or deliquescence of the moderating material during use, improve the quality of the neutron source and prolong the service life.

Disclosed is a moderator for moderating neutrons, including a substrate and a surface treatment layer or a dry inert gas layer or a vacuum layer coated on the surface of the substrate, wherein the substrate is prepared from a moderating material by a powder sintering device through a powder sintering process from powders or by compacting powders into a block, and the moderating material includes 40% to 100% by weight of aluminum fluoride; wherein the surface treatment layer is a hydrophobic material; and the surface treatment layer or the dry inert gas layer or the vacuum layer is used for isolating the substrate from the water in the environment in which the substrate is placed. The surface treated moderator can avoid the hygroscopic or deliquescence of the moderating material during use, improve the quality of the neutron source and prolong the service life.

A radioisotope production apparatus includes a particle accelerator, a first target portion on which a charged particle beam emitted from the particle accelerator is incident and through which the charged particle beam passes, and a second target portion on which the charged particle beam passing through the first target portion is incident. In the first target portion, a target material is held in a beam passage, and a cooling gas supply unit which blows a cooling gas to the target material is provided. In a second target portion, a target substrate is held on a beam axis and a downstream-side surface of the target substrate with respect to the charged particle beam is cooled by cooling water. A total thickness of target foils of the first target portion on the beam axis is smaller than a thickness of the target substrate of the second target portion on the beam axis.

Downhole neutron generators, downhole logging tools that utilize neutron generators, and methods to auto tune downhole neutron generators are disclosed. While a neutron generator is deployed in a borehole of a wellbore, the method includes determining whether an oscillation cycle of an ion beam current generated by the neutron generator is stable. After a determination that the oscillation cycle of the ion beam current is stable, the method includes determining proportional, integral, and derivative parameters of a proportional-integral-derivative controller that is operable to adjust an amount of power supplied to generate ions. The method further includes adjusting a replenish voltage of a replenish power supply of the neutron generator based on the proportional, integral, and derivative parameters.

Downhole neutron generators, downhole logging tools that utilize neutron generators, and methods to auto tune downhole neutron generators are disclosed. While a neutron generator is deployed in a borehole of a wellbore, the method includes determining whether an oscillation cycle of an ion beam current generated by the neutron generator is stable. After a determination that the oscillation cycle of the ion beam current is stable, the method includes determining proportional, integral, and derivative parameters of a proportional-integral-derivative controller that is operable to adjust an amount of power supplied to generate ions. The method further includes adjusting a replenish voltage of a replenish power supply of the neutron generator based on the proportional, integral, and derivative parameters.

Disclosed is a radiation logging tool, comprising a tool housing; a compact generator that produces radiation; a power supply coupled to the compact generator; and control circuitry. Embodiments of the compact generator comprise a generator vacuum tube comprising a source generating charged particles, and a target onto which the charged particles are directed; and a high voltage supply comprising a high voltage multiplier ladder located laterally adjacent to the generator vacuum tube. The high voltage supply applies a high voltage between the source and the target to accelerate the charged particles to a predetermined energy level. The compact generator also includes an electrical coupling between an output of the high voltage supply and the target of the generator vacuum tube to accommodate the collocated positions of the generator vacuum tube and the high voltage power supply.

Disclosed is a radiation logging tool, comprising a tool housing; a compact generator that produces radiation; a power supply coupled to the compact generator; and control circuitry. Embodiments of the compact generator comprise a generator vacuum tube comprising a source generating charged particles, and a target onto which the charged particles are directed; and a high voltage supply comprising a high voltage multiplier ladder located laterally adjacent to the generator vacuum tube. The high voltage supply applies a high voltage between the source and the target to accelerate the charged particles to a predetermined energy level. The compact generator also includes an electrical coupling between an output of the high voltage supply and the target of the generator vacuum tube to accommodate the collocated positions of the generator vacuum tube and the high voltage power supply.

A coolant having a set temperature is fed into the nuclear reactor core of a medical neutron source, which is in a subcritical state. The nuclear reactor core is transitioned from the subcritical state to a critical state until the nominal power of the nuclear reactor is achieved. A neutron output channel is opened in order to conduct a neutron therapy session, and the operation of the reactor is maintained at nominal power while the neutron therapy session is conducted. At the end of the session, the neutron output channel is closed at the same time as the reactor core is transitioned to a subcritical state. The temperature of the coolant entering the core is maintained unchanged and equal to a set temperature, both when the core is transitioned to a critical state and during the operation of the nuclear reactor at nominal power.

A coolant having a set temperature is fed into the nuclear reactor core of a medical neutron source, which is in a subcritical state. The nuclear reactor core is transitioned from the subcritical state to a critical state until the nominal power of the nuclear reactor is achieved. A neutron output channel is opened in order to conduct a neutron therapy session, and the operation of the reactor is maintained at nominal power while the neutron therapy session is conducted. At the end of the session, the neutron output channel is closed at the same time as the reactor core is transitioned to a subcritical state. The temperature of the coolant entering the core is maintained unchanged and equal to a set temperature, both when the core is transitioned to a critical state and during the operation of the nuclear reactor at nominal power.