Directional Neutron Detector

A method for fabrication of plastic scintillation fibers hereinafter fibers, having a diameter of less than 100 microns, using an apparatus comprising

• a pressurized Vessel with an electrically conductive perforated bottom of holes of diameter of the desired fibers, containing a mixture of non-polymerized of plastic scintillator where
• the holes and external surface of the perforated plate are coated with an hydrophobic and non-stick material and
• a Plate supporting an array of conductive needle-like spikes of diameter of less than the diameter of the holes and having the same pitch as the holes, and whose distance from the bottom of the vessel is controlled by a micro-positioning system and two sets of meshes with an aperture slightly larger than the diameter of the holes, where
• one of the meshes is in the beginning of the process inserted onto the array of needle-like spikes and
• the second mesh is connected to the bottom of the vessel at a small distance from the holes and
• a high voltage electrical source connected between the conductive bottom of the vessel and the Plate and
• a microwave source for curing non-polymerized plastic whereas said method consists in
• a. inserting the array of conductive needle-like spikes into the respective holes and
• b. establishing the high voltage field between the needle-like spikes and the bottom of the vessel and
• b. increasing the pressure in said vessel until the non-polymerized mixture starts to seep through the holes of the bottom plate and
• c. heating the seeping out the non-polymerized mixture with the microwave source until it starts to solidify and
• d. Lowering the plate supporting the needle-like spikes at the same rate as the polymerization process of the seeping out mixture and
• e. adjusting the pressure in the vessel to fit the polymerization process and
• f. after the needle-like spikes have exited their respective holes, sliding over the mesh onto the fiber array so that the mixture solidifies within the mesh.

A method for fabrication of plastic scintillation fibers hereinafter fibers, having a diameter of less than lOOmicrons, using an apparatus comprising

• a pressurized Vessel with a linear array of nozzles at its bottom, said nozzles having holes of diameter of the desired fibers, and
• said Vessel containing partly polymerized plastic scintillator and
• heating means to melt the partly polymerized plastic scintillator and
• pressurizing means to extract plastic scintillator fibers from the nozzles and
• a microwave source for helping accelerate the curing process and
• adjustable heated twin rollers to pull and shape the fibers out of the nozzle
• a rectangular faced spool able to rotate on its axis and
• mechanical guides, equal in number to the number of nozzles, with aperture sizes equal to the diameter of the fibers, and
• linear motors for moving the mechanical guides and the square spool laterally at the same speed and
• means for spreading nano-particles onto the layers of fibers whereas said method consists of
• a. setting the right pressure to pull out of the nozzles a linear array of fibers and
• b. setting the temperature and speed of the rollers and
• c. injecting a stream of nanogel particles onto the semi-cured fiber and
• d. setting the microwave power for curing the fiber and
• e. inserting each of the linear array of fibers into its guide and
• f. Wrapping the linear array of fibers onto the revolving and laterally moving spool and
• g. After the winding of fibers on the spool completes one full layer, spread a layer of nanogel particles onto the fibers and the interstices between the fibers and
• h. reverse the direction of the lateral motion and start wrapping the next layer
• i. After the desired number of layers are wrapped one on top of the previous one, cut the array into four 3D arrays.

An apparatus for fabrication of a 3D plastic scintillation fibers array hereinafter fibers, where each fiber has a diameter of less than lOOmicrons, comprising

• a planar mold of hydrophobic material substantially the same dimensions and shape as a planar array of fibers for casting a mixture of liquid plastic scintillator and
• means for polymerizing the plastic scintillator mixture and
• means for disengaging said planar array of fibers after said mixture of plastic scintillator polymerizes and
• means for accurately placing said planar arrays one on top of the other to build a 3D array of the desired dimensions and shape and
• means for spreading between the interstices nano-particles of refractive index of less than 1.30
• means for holding in place the planar arrays after stacking them and
• means for reinforcing the structure after cutting the front and back of the frames supporting the fiber array