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    Process for carrying out nuclear fission reactions
    51.
    发明专利
    Process for carrying out nuclear fission reactions 未知

    公开(公告)号：GB755598A

    公开(公告)日：1956-08-22

    申请号：GB3376554

    申请日：1954-11-22

    Applicant: STICHTING FUND OND MATERIAL

    IPC: G21C1/22

    Abstract: 755,598. Nuclear reactors. STICHTING VOOR FUNDAMENTEEL ONDERZOEK DER MATERIE. Nov. 22, 1954 [Nov. 25, 1953], No. 33765/54. Class 39 (4). To reduce waste of neutrons in a thermal reactor, the initial proportion between the quantities of moderator and fissile material is selected to afford minimum change in reactivity with fluctuations in this proportion. The nuclear fuel is in solution or suspension in a liquid, such as a suspension of UO 2 in D 2 O and the gradual variation in the proportion is effected outside the reactor by separation and/or by adding more fissile material. To compensate for the increased number of neutrons available as Pu 239 is formed from natural uranium and U 235 is consumed, some of the uranium is replaced by impoverished uranium, such as waste product from diffusion plants producing U 235 . Alternatively the fissile material may be diluted with Th 232 . For a reactor of radius Rc, the ratio of D 2 O to UO 2 that produces a neutron reproduction factor of unity is shown by curve 1 for natural uranium, and by curve 2 for fissile material having all U 235 replaced by Pu 239 during operation. Curve 3 represents dilution with 30 per cent U 238 and formation of 0.55 per cent PU 239 , so that with a radius 7 there is comparatively little change of reactivity with variation of D 2 O to UO 2 ratio.

    Thin-film radiation detector
    55.
    发明专利
    Thin-film radiation detector 未知

    公开(公告)号：GB2466946A

    公开(公告)日：2010-07-21

    申请号：GB0900534

    申请日：2009-01-14

    Applicant: UNIV LEIDEN ,  STICHTING FUND OND MATERIAL

    Inventor： DRIESSEN EDUARD FRANS CLEMENS ,  DOOD MICHIEL JACOB ANDRIES DE

    IPC: G01J1/04 ,  G01J1/42 ,  H01L39/10

    Abstract: A method of operating a thin-film radiation detector such as a superconducting single photon detector (SSPD) comprises the steps of selecting a first polarization state of an incident beam of radiation; and directing the resulting first polarized beam of radiation at the thin-film detector surface such that the beam axis is oblique to the plane of the detector surface and the first polarized beam has an s-polarization state relative to the absorption surface of the detector. The thin-film radiation detector comprises an absorbing thin film material 3 defining the detector surface disposed between a substrate 2 and a second material 12 such as air. Coupling optics 4 includes a polarizer 6 and prism 7. The angle of incidence of beam 8 is close to the critical angle for total internal reflection. The absorbing thin film may comprise a meander of superconducting material (Fig-2). The detector may comprise a two-stage detector for capturing both polarization states of incident light on two thin-film detectors (Fig.9).

    57.
    发明专利
    未知

    公开(公告)号：AT392701T

    公开(公告)日：2008-05-15

    申请号：AT05825377

    申请日：2005-12-15

    Applicant: STICHTING FUND OND MATERIAL

    Inventor： KESSELS MARCUS ,  VERHOEVEN JAN

    IPC: G21K1/06

    Abstract: Multi-layer mirror for radiation with a wavelength in the wavelength range between 0.1 nm and 30 nm, comprising a stack of thin films substantially comprising scattering particles which scatter the radiation, which thin films are separated by separating layers with a thickness in the order of magnitude of the wavelength of the radiation, which separating layers substantially comprise non-scattering particles which do not scatter the radiation, wherein the separating layers are covered on at least one side in each case by an intermediate layer of a material which can be mixed with the material of the thin films and the material of the separating layers.

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