Abstract: A first chopper between a laser device and a semiconductor substrate chops an excitation light at a specific frequency, and a second chopper between the first chopper and the semiconductor substrate chops the excitation light at a variable frequency higher than the first chopper. A photoluminescence light emitted by the semiconductor substrate when the semiconductor substrate is intermittently irradiated with the excitation light is introduced into a monochromator. A controller obtains the decay time constant T of the photoluminescence light from variation of the average intensity of the photoluminescence light when gradually increasing the chopping frequency of the excitation light by controlling the second chopper, and computes the life time &tgr; of the semiconductor substrate from an expression “&tgr;=T/C”, where C is a constant.

Abstract: An infrared motion sensing apparatus mounted within the canopy of a decorative lighting fixture where the apparatus may be vertically adjusted. The apparatus comprises a pyroelectric infrared sensor located in a stationary base. Mounted over the sensor and movable in a vertical direction is a Fresnel lens array. The array is mounted to a frame that is constrained to ride on the base in a vertical direction in response to the rotation of a screw. The canopy has an opening to allow radiation to be received by the sensor and a second opening for a stem of the screw so that manipulation of the stem may take place without disassembly of any part of the lighting fixture.

Abstract: The present invention is a dynamic radiation scanning system for detecting radiation dosimetry of a beam emitted along an axis from a radiotherapy treatment machine and a method for its use. The system contains a dosimetry probe to sense photons and electrons, a dynamic phantom body formed from a material having a density approximating that of the human body, a gantry mounting assembly rigidly attached to the radiotherapy machine for positioning of the phantom body, and a lead screw assembly rigidly affixed to the gantry for providing coplanar movement of the dynamic phantom within a plane perpendicular to the axis of radiation emission. Movement of the dynamic phantom through a series of locations is carried out at varying depths and angles so as to provide sufficient data to determine variations in beam uniformity, thereby providing for simple and reliable testing and calibration of the machine.

Abstract: When first and second PbSe detectors 6 and 7 are irradiated with intermittent infrared radiation from a light source 3, infrared radiation detection circuits 21a and 21b output electrical signals in accordance with the magnitude of the infrared radiation, respectively. The output signals are supplied as they are to a CPU 32 via A/D converter 31, and, on the other hand, AC signals of the output signals via AC components detection circuits 22a and 22b reach the CPU 32. The CPU 32 corrects the AC signals, based on data which relates to the resistances and sensitivities of the PbSe detectors 6 and 7 and which are stored in an EEPROM 23, and the DC components of the output signals of the infrared radiation detection circuits 21a and 21b.

Abstract: A closed-loop stabilization system and method for a radiation detector system including a scintillator and a light sensing device for detecting the scintillation light produced in the scintillator through interaction with impinging radiation. A spectrally stable gamma ray measurement for downhole and other non-isothermal gamma ray measurement applications is obtained by use of a light source for emitting photons, preferably ultra-violet photons, into the scintillator that are not detectable by the light sensing device. The light source causes the scintillator to fluoresce at a wavelength detectable by the light sensing device, and the change in measured fluorescence is used to adjust system gain to account for variations in scintillator output attributable to environmental conditions. In this manner, the stabilization system adjusts the system gain to maintain consistency among radiation measurements over a wide temperature range.