Detector

About: Detector is a research topic. Over the lifetime, 146515 publications have been published within this topic receiving 1351476 citations.

A two-dimensional scintillation detector for small angle neutron scattering

Abstract: A two-dimensional position-sensitive 6 Li glass scintillation detector for neutrons has been constructed and put into operation in a 40 m long small angle neutron scattering instrument. The detector has a detection area of 60 × 60 cm, a neutron capture probability of 96% for subthermal neutrons of 8 A wavelength, a spatial resolution of 8 mm adapted to the scattering experiments, and a counting ability of 100 kHz. The Anger type camera consists of 8 × 8 photomultipliers of 3 in. diameter arranged in a square lattice with 8.4 cm lattice constant. In a coarse fine procedure a neutron capture event is addressed by determining the photomultiplier with maximum anode signal and by a division procedure involving the nine relevant signals of the 3 × 3 photomultiplier matrix centered at the maximum photomultiplier signal. The gain of each photomultiplier is kept constant in time by a gain stabilizing system. Construction, data processing and properties of the detector are described. A few small angle scattering patterns from polymer samples are presented.

Frequency and phase lock loop synchronous detecting system having a pair of phase lock conditions

Abstract: A synchronous detecting system includes an automatic phase and frequency control system having a pair of multipliers coupled to a television tuner. A detector oscillator is also coupled to each of the multipliers. Means are provided to phase shift the oscillator signal at one multiplier such that quadrature beat signals are produced. The output of one of the multipliers is coupled directly to a third multiplier while the output of the other is coupled to a low pass filter. The filtered signal is amplitude limited and applied to the third multiplier and produces an information control signal. In two of the described embodiments, a second low pass filter couples the output of the third multiplier to the frequency control input of a voltage controlled detector oscillator. Two other embodiments are disclosed in which the tuner oscillator is controlled while the detector oscillator is maintained constant. The frequency and phase control system has two equal probability stable phase lock conditions. An inverter selectively operable responsive to the limiter information control assures the correct polarity of recovered information.

Self tuned ultrasonic generator system having wide frequency range and high efficiency

Abstract: This self tuned ultrasonic generator system for driving a piezoelectric transducer has a phase lock loop circuit for automatically finding and maintaining optimum drive of the transducer over a frequency range of at least 25% of a specified center frequency, regardless of variations of load, temperature, and configurations of the transducer. The loop circuit employs a voltage controlled oscillator driving a switching amplifier which powers the transducer. The signal from the oscillator is fed to a digital phase detector which receives as another input a sample of the current driving the transducer such that a phase comparison voltage from the detector is 15 applied to and controls the voltage of the oscillator. Another current sample is applied to a power supply to control the power supplied to the switching amplifier.

Optical imaging system with movable scanning unit

Abstract: The present invention generally relates to optical imaging systems and methods thereof for providing images of two- and/or three-dimensional distribution of properties of chromophores in various physiological media. In particular, the present invention provides preferred embodiments of optical imaging systems, optical probes, sensor assemblies, and methods thereof for utilizing movable scanning units. A typical optical imaging system includes at least one wave source, wave detector, movable member, and actuator member. The wave source emits electromagnetic waves into a target area of the physiological medium and the wave detector generates output signal in response to electromagnetic waves detected thereby. The wave source and detector are disposed at the movable member which is moved by the actuator member so that at least one of the wave source and detector moves over different regions of the target area while generating the output signal thereby. Accordingly, the optical imaging system and optical probes of the present invention can scan the target area which is substantially larger than the scanning area of its scanning unit.