53 results about "High count rate" patented technology

A method and associated apparatus for detecting concealed fissile, fissionable or special nuclear material in an article, such as a shipping container, is provided. The article is irradiated with a source of fast neutrons, and fast neutrons released by the fissile or fissionable material, if present, are detected between source neutron pulses. The method uses a neutron detector that can detect and discriminate fast neutrons in the presence of thermal neutrons and gamma radiation. The detector is able to process high count rates and is resistant to radiation damage, and is preferably a solid state neutron detector comprised of silicon carbide.

The invention discloses a gamma-ray-energy-spectrum measurement method at a high counting rate. Firstly, output of a detector is connected with input of a high-speed analog-digital converting device and output of the high-speed analog-digital converting device is connected with input of a digital-signal processing device. Output current signals of the detector are directly converted into digital signals. The converted digital signals are processed and information representing energy of to-be-detected rays is extracted so that the energy spectrum of to-be-detected Gamma rays is given. The gamma-ray-energy-spectrum measurement method at the high counting rate solves problems that spectrometer measurement counting rate is limited by traditional spectrometer electronic systems and energy resolution of conventional high-counting-rate spectrometers is hard to ensure. The gamma-ray-energy-spectrum measurement method at the high counting rate is capable of realizing gamma-ray-energy-spectrum measurement at a counting rate of 106cps or higher and ensuring excellent energy resolution.

A method of TOF-PET image reconstruction using time-truncated TOF-PET projection data. The time-truncated TOF-PET data is obtained by narrowing the scanner time window to a smaller “time window field of view,” which reduces the field of view of a TOF-PET scanner. This results in a lower list mode stream transfer rate, which can be useful in high count rate data acquisitions, in particular ⁸²Rb cardiac studies.

The invention relates to a method and a pulse processing circuit (100) for the processing of current pulses (CP) generated by incident photons (X) in a piece of converter material, for instance in a pixel (11) of a radiation detector. Deviations of the pulse shape from a reference are detected and used to identify pulse corruption due to pile-up effects at high count rates and/or charge sharing between neighboring pixels. The deviation detection may for instance be achieved by generating, with a pulse shaper (110), bipolar shaped pulses from the current pulse (CP) and/or two shaped pulses of different shapes which can be compared to each other.

The present invention relates to methods and an apparatuses for loading and unloading objects into/from corresponding cavities in holders at a high count rate. For loading, a plurality of objects are present on an object path which mutually converges with a holder path. For unloading, the object path mutually diverges from the holder path. Integration of this method and apparatus respectively into a method of manufacturing unleaky containers and a corresponding apparatus for leak testing containers is also proposed.

The invention relates to a high-counting-rate space charged particle detector. The detector comprises a collimator, a probe upper cover plate, a light shielding piece, a first sensor, a second sensor, a third sensor, a fourth sensor, a probe shell, and a probe shell bottom plate. The deposition energy [delta]E of charged particles in the first sensor is converted into a 6-bit binary code by using a digital pre-amplification circuit. The ranges Rs of the charged particles in the second sensor, the third sensor, and the fourth sensor are converted into 3-bit binary codes by using another three digital pre-amplification circuits. The row of a look-up table corresponds to the 6-bit binary code in correspondence with the energy [delta]E deposited in the first sensor. The columns of the look-up table correspond to the 3-bit binary codes in correspondence with the ranges Rs in the second sensor, the third sensor, and the fourth sensor. The binary codes are delivered to the look-up table in an electronics storage unit of the detector for matching. By virtue of matching, the energy E and the type of the space charged particles entering into the detector can be obtained.

Method and system are provided for calibrating a nuclear medical imaging apparatus for DC shift caused by gamma event afterglow pulses. Detector responses to weak and to high count rate radiation sources are compared with each other, and a zero correction value is incremented until the detector response is the same for the weak source and the high count rate source. The zero correction value is then stored as a static zero correction value, which multiplies a dynamic zero correction value obtained just prior to the occurrence of a gamma event, in order to remove the effects of DC shifts from the output energy signal Esum.

The invention discloses a pulse waveform transformation method which is used for trapezoidal forming of non-standard negative exponential nuclear pulse signals. The method comprises: firstly, expressing a non-standard negative exponential nuclear pulse signal with a slowed rising edge as a double-exponential form; secondly, discretizing the double-exponential pulse signal, and performing Z transformation; then, carrying out Z transformation of trapezoidal pulses, solving a transfer function of trapezoidal forming, and establishing a recursion formula of trapezoidal forming, wherein related parameters in the recursion formula are obtained through a genetic algorithm. According to the method, trapezoidal forming of the nuclear pulse signal with the rising edge becoming slow is achieved to acertain extent, the symmetry of trapezoidal pulses is improved, accurate acquisition of pulse amplitudes is facilitated, improvement of the system energy resolution and increase of the counting rate are facilitated, and the method has great significance in improving the accuracy of radioactivity measurement.

The invention provides a superconducting nanowire single photon detection system provided with an impedance matching transmission line. The system comprises a superconducting nanowire single photon detector (SNSPD), the 1/4 wavelength impedance matching transmission line, a high-pass filter, a three-port device, a current source and an amplifier, wherein one end of the 1/4 wavelength impedance matching transmission line is connected with the SNSPD; one end of the high-pass filter is connected with the end, connected to the SNSPD, of the 1/4 wavelength impedance matching transmission line, andthe other end of the high-pass filter is grounded; a first port of the three-port device is connected with the end, away from the SNSPD, of the 1/4 wavelength impedance matching transmission line; oneend of the current source is connected with a second port of the three-port device; and the input end of the amplifier is connected with a third port of the three-port device, and the grounded end ofthe amplifier is grounded. Through the system, matching reading of a specific frequency signal can be realized, amplification of a pulse amplitude is realized; and time jitter is lowered; and low-frequency components in the signal can be shaped and removed, so that the counting rate and detection rate are increased.

The invention discloses a random pulse multichannel amplitude analyzer under a high counting rate, and an FPGA single chip is used to complete main functions. In an FPGA, a digital detector pulse signal is differentiated, and a differential signal is used to generate a pulse start and stop signal which controls the pulse amplitude detection. When the pulse start and stop signal is invalid, the estimation of a baseline value of a detector pulse signal is started, the maximum value of the detector pulse signal is detected when the pulse start and stop signal is valid, and a corresponding amplitude value of a detector pulse is obtained by subtracting the currently estimated baseline value from the maximum value. A number of pulses of a corresponding differential signal is judged in a certain time after the detector pulse signal is valid, if the pulse number is larger than or equal to 2, detector pulse signal stacking is judged, and the pulses are not included in an energy spectrum.

The invention discloses a device and a method for gamma-ray energy spectrum counting measurement, and belongs to the technical field of gamma-ray energy spectrum measurement. The device comprises an amplification circuit, a plurality of measurement branches, a logic control circuit and a storage circuit, wherein the amplification circuit receives a gamma ray energy signal and converts the gamma ray energy signal into an analog signal; the measurement branches receive the analog signal, send conversion start signals to the logic control circuit, search analog signal peak positions, maintain the level of the peak positions, convert the level into digital signals and output the digital signals; the logic control circuit is used for receiving the conversion start signals, sending the conversion start signals to delay preset time, closing a measurement branch and opening the next measurement branch; and the storage circuit is used for receiving the digital signals and determining the counting value of the gamma-ray energy spectrum according to the received digital signals output by the plurality of measurement branches. According to the invention, the counting rate of the gamma-ray energy spectrum is greatly improved, and the restriction of the counting rate is mainly restricted by the attenuation time of a scintillator.