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 high enumeration rate single photon detector characterized by that, in the existing single photon detector circuit an active quick-speed recovery circuit is arranged comprising an electronic switchand a control circuit, the electronic switch is connected between the anode and the earth terminal of the snow slide diode for controlling the start and stop of the electronic switch. During the recovery time, the control circuit exports a positive pulse, making the electronic switch conducting, the node capacitor and the distributed capacitor of the avalanche diode are quickly charged to Va and discharged to 0 volt respectively through the small resistance electronic switch.

Provided is an accumulation event detection and reconstruction method which comprises the steps that: a flicker pulse database of non-accumulation conformation single events under low count is acquired, average pulse of the flicker pulse database of each path of the non-accumulation conformation single events is obtained, and shape information of flicker pulse is designated by average pulse; de-convolution is performed by adopting an MLEM algorithm, and arrival time of flicker pulse is defined as peak time of a de-convolution sequence; the single events in accumulation are segmented by adopting an MAP criterion, and the energy value of the events is extracted via summarizing; and the acquired shape, time and energy information is stored as table data so that accumulation event reconstruction is completed. When the system is in operation, each single event in accumulation can be effectively detected, segmented and recovered so that system counting rate is effectively increased, energy resolution under high counting rate is enhanced, and thus the method is especially suitable for processing of various accumulation events in an offline environment.

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.

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 invention discloses a high-counting-rate multi-gap resistive plate chamber detector. The high-counting-rate multi-gap resistive plate chamber detector comprises a plurality of MRPCs (multi-gap resistive plate chambers), at least one insulated baffle block which is used for mutually isolating the MRPCs by a preset distance, a plurality of connectors, two insulated films and two reading circuit boards, wherein at least one insulated baffle block and the MRPCs are arranged between the two insulated films, the two insulated films are arranged between the two reading circuit boards, and the two reading circuit boards are connected through the connectors. According to the high-counting-rate multi-gap resistive plate chamber detector, the MPRCs are spliced between the two reading circuit boards without being stacked, so that the cost is low, the needed space (or thickness) is small; moreover, the detecting efficiency for each MRPC can be as high as 95%, and the time resolution is superior to 100ps.

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.

The invention discloses a radioactive pulse amplitude digital discriminator. The radioactive pulse amplitude digital discriminator comprises a signal follower module, a high-speed analog / digital (AD) converter, a field-programmable gate array (FPGA) data acquisition and processing molding module and the like, wherein the signal follower module realizes high-speed acquisition of signals by using a high-speed linear amplifier, and is connected with the high-speed AD converter; the high-speed converter finishes high-speed digital quantization of pulse signals and then inputs the signals to the FPGA data acquisition and processing molding module; and the FPGA data acquisition and processing molding module finishes front edge and back edge identification of radioactive pulses, caching of pulse data, processing and molding of the pulse data, and the molded pulses can be output to a scaler or a counter for counting and scaling, and also can be transmitted to a singlechip system to finish pulse counting to ensure that a computer can detect and display the pulses. The radioactive pulse amplitude digital discriminator solves the problems of superimposition and calibration of the radioactive pulses during high-count-rate measurement.

Systems and methods are provided to perform dead time correction. An observed ion count rate is obtained using a non-paralyzable detection system of a mass spectrometer. The detection system includes an ion detector, a comparator / discriminator, a mono-stable circuit and a counter. The non-paralyzable detection system exhibits dead time extension at high count rates. The extension of the dead time occurs because the mono-stable circuit requires a rising edge to trigger and can only be triggered again after the output pulse from the comparator / discriminator has gone low. This allows a second comparator / discriminator pulse arriving just before the end of the dead time started by a first comparator / discriminator pulse to extend the dead time to the trailing edge of the second comparator / discriminator pulse. A true ion count rate is calculated by performing dead time correction of the observed ion count rate.

The invention discloses a Gaussian-like forming method, which is used for carrying out Gaussian-like forming filtering convolution processing on an input signal, comprises two times of convolution processing, and comprises the following steps: S1, carrying out first convolution processing on an input signal to realize bipolar forming; and S2, carrying out second convolution processing on the signal obtained in the step S1 to realize Gaussian-like forming. The method has the advantages of Gaussian forming and bipolar forming at the same time, has good anti-noise capacity while achieving high-resolution energy spectrum, and has baseline drift resisting capacity compared with a common digital forming method. Due to the fact that the method is fully digital, parameters of digital Gaussian shaping are easy to adjust compared with analog Gaussian shaping, and compared with a digital S-K filter, trailing of pulses is removed, the symmetry is better, the pulse is narrower, and the digital Gaussian shaping is suitable for energy spectrum measurement at a high counting rate. In order to improve the filtering effect, the digital Gaussian shaping method can be repeatedly used twice to achieve a better effect.

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.

Systems and methods are provided to perform dead time correction. An observed ion count rate is obtained using a non-paralyzable detection system of a mass spectrometer. The detection system includes an ion detector, a comparator / discriminator, a mono-stable circuit and a counter. The non-paralyzable detection system exhibits dead time extension at high count rates. The extension of the dead time occurs because the mono-stable circuit requires a rising edge to trigger and can only be triggered again after the output pulse from the comparator / discriminator has gone low. This allows a second comparator / discriminator pulse arriving just before the end of the dead time started by a first comparator / discriminator pulse to extend the dead time to the trailing edge of the second comparator / discriminator pulse. A true ion count rate is calculated by performing dead time correction of the observed ion count rate.

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 relates to the technical field of nuclear signal processing, in particular to a nuclear pulse signal processing method, electronic equipment, a storage medium and a program product. The method comprises the steps of obtaining a stacking nuclear pulse signal; extracting available nuclear pulse signals in the stacked nuclear pulse signals; and analyzing the available nuclear pulse signal to obtain nuclear pulse signal detection information. The method is used for solving the problem that the nuclear pulse signal processing efficiency is low in the nuclear radiation measurement process in the prior art, nuclear radiation counting loss and time cost increase caused by directly abandoning accumulated nuclear pulse signals are avoided, and the nuclear pulse signal processing efficiency is improved. Especially under the condition of a high counting rate, even if the nuclear pulse signal has a pulse accumulation problem, the nuclear pulse signal detection information required by a user can be obtained from the accumulated nuclear pulse signal, the pulse detection capability is improved, and the completeness and accuracy of nuclear radiation monitoring are improved.

There are provided a storage section 220 that stores an output value read out by counting a pulse signal of incident X-rays, by a photon-counting type semiconductor detector; and a calculation section 230 that calculates a count value based on the output value that has been read out, wherein the calculation section 230 uses a model in which an apparent time constant of the pulse signal monotonously decreases against increase in pulse detection ratio with respect to exposure. According to such a model, the corresponding apparent time constant is able to be obtained even in any higher count rate. As a result of this, reduced can be the influence of count loss even on the count rate that has not been able to be covered by the conventional method.

A method for real-time processing of pulse accumulation events, comprising the steps of: generating a fitted baseline value lookup table and a fitted energy value lookup table for pulse falling edges, using a multi-voltage threshold sampling method to complete the identification of piled-up pulses and the triggering of the pulse signal processing process ; Using the pulse prior information and the collected pulse information to obtain the information of the incorrectly sampled part due to the pulse accumulation in the form of a look-up table, the real-time recovery of the accumulated pulse information is completed. The present invention first uses the multi-voltage threshold sampling method to complete the recognition of the accumulation pulse at a high count rate and the triggering of the pulse signal processing process, and then uses the pulse prior information and the collected pulse information to obtain The information of the sampling part completes the real-time recovery of the accumulation pulse information. The method of the present invention is simple and efficient, and is easy to implement on a real-time data acquisition system at the detector level, and can still achieve better accumulation of pulse information recovery effect under the condition of low sampling rate.

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.