| 摘要 |
<p>1,225,058. Local viewing. UNITED KING- DOM ATOMIC ENERGY AUTHORITY. 12 Aug., 1969 [26 Aug., 1968], No. 40785/68. Heading H4F. A neutron detector, e.g. for determining crystal structures by neutron diffraction, or for neutron radiography, comprises a sheet 1 of a neutron scintillator and a two-dimensional array of photomultiplier tubes 8 optically coupled to the sheet 1 so that a scintillation at any position on the sheet 1 is received at each tube 8, and the outputs of the tubes 8 are combined, e.g. in a capacitor network 11, to produce a signal representative of the scintillation position for the circuitry of a cathode-ray tube 20 or a computer store. As described, the optical coupling is provided by a neutron absorbing sheet 5 of boron loaded glass, and a single, or two, sheets 6, 7 of polymethyl-methacrylate, although fluids may also be used, and the sheet 1 is a zinc sulphide plastic phosphor loaded with lithium fluoride. A collimator of two orthogonal sets 3, 4, of parallel cadmium strips is provided. Four signals from the network 11 convey all the necessary pulse height and position information. These are added at 19 and fed to a circuit 21, e.g. as described in Specification 911, 116, which distinguishes pulses due to neutrons and gamma rays by their length, and applies a bright-up signal to the tube 20 for neutrons. Ratio circuits 17, 18, derive the XY position coordinates which are fed to the tube 20 together with brightness information from 19. Fig. 2 (not shown) illustrates the apparatus mounted for use in neutron diffraction studies.</p> |
