82 results about "Epithermal neutron" patented technology

A method for determining at least one formation property calculated from neutron measurements acquired with a downhole tool includes emitting neutrons from a source in the tool into the formation, detecting neutrons with at least one detector in the downhole tool, calculating a first slowing-down length (L1) based on the detected neutrons, and deriving a second slowing-down length (L2) based on the first slowing-down length (L1). Further steps include deriving a correlation function for relating slowing-down lengths from a first tool to slowing-down lengths associated with a different source, wherein the correlation function depends on formation properties such as bulk density; and applying the correlation function to the slowing-down length of the first tool to derive the slowing-down length of the second tool. A method for determining a thermal neutron formation porosity based on a slowing-down length from epithermal neutron measurements from an electronic neutron source includes converting the slowing-down length into a computed neutron slowing-down length from thermal neutron measurements from a chemical neutron source, wherein the converting uses a correlation function that depends on formation bulk density; deriving a thermal neutron countrate ratio based on the computed neutron slowing-down length, wherein the deriving uses a function that depends on the formation bulk density and formation sigma; and computing the thermal neutron formation porosity from the thermal neutron countrate ratio.

The invention provides a beam shaping body for the neutron capture therapy. The beam shaping body comprises a beam inlet, a target material, a speed-retarding body adjacent to the target material, a reflector arranged to surround the outside of the speed-retarding body, a thermal neutron absorber adjacent to the speed-retarding body, a radiation shield arranged inside the beam shaping body, and a beam outlet. The nuclear reaction occurs between the target material and a proton beam that shoots into the beam inlet to generate neutrons, and the neutrons form a neutron beam which defines a main axis. The speed-retarding body slows down the neutrons generated from the target material to an epithermal neutron energy region. The speed-retarding body comprises the following materials of MgF2 and 6LiF, wherein the weight percentage of 6LiF to MgF2 is 0.1-5%. The above materials, in the form of powders or powder-pressed blanks, are subjected to powder sintering treatment by powder sintering equipment to turn into blocks. The reflector guides the neutrons deviating from the main axis back to the main axis so as to improve the intensity of an epithermal neutron beam. The thermal neutron absorber is used for absorbing thermal neutrons so as to avoid the excessive dose of the neutrons during the treatment on shallow normal tissues. The radiation shield is used for shielding leaky neutrons and photons so as to reduce the dose thereof on normal tissues in non-irradiated regions.

A beam shaping assembly for neutron capture therapy includes a beam inlet, a target having nuclear reaction with an incident proton beam from the beam inlet to produce neutrons forming a neutron beam defining a main axis, a moderator adjoining to the target, a reflector surrounding the moderator, a thermal neutron absorber adjoining to the moderator, a radiation shield arranged inside the beam shaping assembly and a beam outlet. The neutrons are moderated to epithermal neutron energies. The reflector leads the neutrons deviated from the main axis back, and a gap channel is arranged between the moderator and the reflector. The thermal neutron absorber is used for absorbing thermal neutrons so as to avoid overdosing in superficial normal tissue during therapy. The radiation shield is used for shielding leaking neutrons and photons so as to reduce dose of the normal tissue not exposed to irradiation.

Disclosed is a beam shaping assembly, including a beam inlet; a target, wherein the target has nuclear reaction with the incident proton beam; a moderator adjoining to the target, wherein the neutrons are moderated by the moderator to epithermal neutrons; a reflector surrounding the moderator, and leads the deflected neutrons back to the moderator to enhance the epithermal neutron beam intensity; and a cooling system, wherein the cooling system comprises a first cooling part for cooling target, a second cooling part and a third cooling part connecting with the first cooling part and extending in a direction parallel to the axis of the accelerating tube respectively, the first cooling part connects with the target in a face to face manner, the cooling medium is inputted into the first cooling part from the second cooling part and is outputted from first cooling part through the third cooling part.

In order to improve flux and quality of neutron sources, the disclosure provides a beam shaping assembly for neutron capture therapy includes: a beam inlet; a target, wherein the target has nuclear reaction with an incident proton beam from the beam inlet to produce neutrons; a moderator adjoining to the target, wherein the neutrons are moderated by the moderator to epithermal neutron energies, the moderator includes a main body and a supplement section surrounding the main body, the main body and the supplement section form at least a tapered structure; a reflector surrounding the moderator; a thermal neutron absorber adjoining to the moderator; a radiation shield arranged inside the beam shaping assembly, wherein the radiation shield is used for shielding leaking neutrons and photons so as to reduce dose of the normal tissue not exposed to irradiation; and a beam outlet.

A neutron moderation material for use in a BNCT beam shaping assembly. The neutron moderation material comprises three elements, i.e., Mg, Al, and F, wherein the mass fraction of the Mg element is 3.5%-37.1%, the mass fraction of the Al element is 5%-90.4%, and the mass fraction of the F element is 5.8%-67.2%; the sum of the weights of the Mg, Al, and F elements is 100% of the total weight of the neutron moderation material. The neutron moderation material may be doped with a small amount of 6Li-containing substances, and the addition of the 6Li-containing substances effectively decreases the content of γ-rays in epithermal neutron beams.

The present disclosure provides a neutron capture therapy system including a beam shaping assembly. The beam shaping assembly includes a beam inlet; a neutron generator arranged into the beam shaping assembly, the neutron generator has nuclear reaction with an incident proton beam from the beam inlet to produce neutrons; a moderator adjacent to the neutron generator, the neutrons are moderated by the moderator to epithermal neutron energies; a reflector surrounding the neutron generator and the moderator, the reflector leads the deflected neutrons back to enhance epithermal neutron beam intensity; a beam outlet; and at least a movable member moving away from or close to the neutron generator, the movable member moves between a first position where the neutron generator is replaceable, and a second position where the neutron generator is irreplaceable. The neutron capture therapy system has a simple structure, and the neutron generator is easy to be replaced.

In order to improve the flux and the quality of a neutron source, the invention provides a beam shaping body for neutron capture therapy. The beam shaping body comprises a beam inlet, a target, a retarding body adjacent to the target, a reflecting body surrounding the external of the retarding body, a thermal neutron absorber adjacent to the retarding body, and a radiation shield and a beam outlet formed in the beam shaping body, wherein the target has nuclear reaction with proton beam entering from the beam inlet, so as to produce a neutron; the neutron forms a neutron beam; the neutron beam defines a main axis; the retarding body slows down the neutron produced by the target to an epithermal neutron energy region; the retarding body is designed to a shape containing at least one cone; the reflecting body guides the neutron deviated from the main axis back to the main axis, so as to improve the strength of an epithermal neutron beam; the thermal neutron absorber is used for absorbing a thermal neutron, so as to prevent the thermal neutron from causing excessive dosage with a superficial normal tissue during therapy; the radiation shield is used for shielding leaked neutron and photon, so as to reduce the normal tissue dosage of a non-irradiated region.