637 results about "Counting rate" patented technology

A CT detector capable of energy discrimination and direct conversion is disclosed. The detector includes multiple layers of semiconductor material with the layers having varying thicknesses. The detector is constructed to be segmented in the x-ray penetration direction so as to optimize count rate performance as well as avoid saturation. The detector also includes variable pixel pitch and a flexible binning of pixels to further enhance count rate performance.

A system for detecting and graphically displaying a contents of a fast-moving target object comprises: a radiation source, having a position such that at least a portion of radiation emitted from the radiation source passes through the fast-moving target object, the fast-moving target object having a variable velocity and acceleration while maintaining a substantially constant distance from the radiation source and being selected from the group consisting of: a vehicle, a cargo container and a railroad car; a velocity measuring device configured to measure the variable velocity of the fast-moving target object; a detector array comprising a plurality of photon detectors, having a position such that at least some of the at least a portion of the radiation passing through the target object is received thereby, the detector array having a variable count time according to the variable velocity and a grid unit size; a counter circuit coupled to the detector array for discretely counting a number of photons entering individual photon detectors, the counter circuit measuring a count rate according to a contents within the fast-moving target object; a high baud-rate interface coupled to the counter circuit for sending count information from the counter circuit at a rate fast enough to support real-time data transfer therethrough; and a processor coupled to the velocity measuring device and to the high-baud-rate interface, receiving count information from the high baud-rate interface and generating distortion-free image data in real time as a function of the count information and the variable velocity. A method for using the system is also disclosed.

Method for evaluating cement quality in a cased well. A density log of the well is obtained using, for example, a GammaRay sources and detectors (51). The detector count rates are inverted to provide initial estimates of cement density and thickness (53). Acoustic waveform data are obtained from the well using an acoustic logging tool (52). The acoustic data are inverted (54-56), using the initial estimates of cement density and thickness obtained from the density logs, and an updated density log is inferred. Cement images are obtained from the updated density log, and cement bond quality can be estimated (57).

A CT detector capable of energy discrimination and direct conversion is disclosed. The detector includes multiple layers of semiconductor material with the layers having varying thicknesses. The detector is constructed to be segmented in the x-ray penetration direction so as to optimize count rate performance as well as avoid saturation.

A method for correcting at least one of pileup effects or charge sharing effects in multi-cell photon counting detectors includes determining a correction coefficient using a count rate of an entire spectrum and applying the determined correction to the counts recorded in an energy window of interest.

The invention discloses an integrated gating active quenching/restoring circuit. The integrated gating active quenching/restoring circuit comprises a quick detection circuit, a pulse generation circuit, a pixel control circuit, a quenching circuit and a restoring circuit, wherein the quick detection circuit is used for processing a detected anode current signal of an SPAD (Single Photon Avalanche Diode) into a pulse signal, the pulse signal can be output through the pulse generation circuit, the pixel control circuit is controlled by an output signal and a gating signal of the pulse generation circuit, the restoring circuit and the quenching circuit are respectively controlled by outputs of the pixel generation circuit, outputs of the restoring circuit and the quenching circuit can be fed back to an anode of the SPAD, and the restoring and the quenching of the SPAD can be controlled. According to the integrated gating active quenching/restoring circuit disclosed by the invention, by adopting a gating control method, the dark counting rate of the SPAD can be effectively reduced, the quenching time can be controlled by the pulse generation circuit, and the integrated gating active quenching/restoring circuit has the advantages of compact area and low power consumption.

Methods and means for measuring and adjusting the gain of a photomultiplier tube (PMT), or other photo-detector with electron multiplication gain, for the purpose of achieving accurate light measurement, such as in a luminescent radiation dosimeter reader. With a PMT illuminated by a light emitting diode or other light source, the PMT output signal is measured in two modes, signal integration and photon pulse counting. The measured PMT gain is calculated as the ratio of the integrated signal to the photon pulse count. The PMT high voltage may be adjusted to cause the measured PMT gain to correspond to an established calibration gain value, or the data from the PMT may be adjusted to compensate the deviation of the measured PMT gain from the calibration gain value. The light source may be a controllable light source that can be adjusted to provide a specific photon count rate output as measured by the PMT. This invention provides for maintaining light measurement calibration without requiring temperature stabilization or a fixed light source.

For small angles that are near critical angle, a primary incident X-ray beam has excellent depth resolution. A series of X-ray fluorescence measurements are performed at varying small angles and analyzed for depth profiling of elements within a substrate. One highly useful application of the X-ray fluorescence measurements is depth profiling of a dopant used in semiconductor manufacturing such as arsenic, phosphorus, and boron. In one example, angles are be varied from 0.01° to 0.20° and measurements made to profile arsenic distribution within a semiconductor wafer. In one embodiment, measurements are acquired using a total reflection X-ray fluorescence (TXRF) type system for both known and unknown profile distribution samples. The fluorescence measurements are denominated in counts/second terms and formed as ratios comparing the known and unknown sample results. The count ratios are compared to ratios of known to unknown samples that are acquired using a control analytical measurement technique. In one example the control technique is secondary ion mass spectroscopy (SIMS) so that the count ratios from the TXRF-type measurements are compared to ratios of integrals of SIMS profiles. In another example, the TXRF-type measurement ratios are compared to simulation profiles of known samples. Integrals of the SIMS profile that vary as a function of depth into the substrate correspond to the grazing incidence angles of the TXRF-like measurement and respective count rates.

The present invention provides for method and an apparatus for determining the porosity of a geological formation surrounding a cased well. The method further comprises of generating neutron pulses that release neutrons into an area adjacent the well, from a neutron source. Neutrons are sensed and a plurality of neutron detector count rates is acquired using at least two neutron source to neutron detector spacings. A timing measurement is acquired at one of the spacings to measure a first depth of investigation. A ratio of the neutron detector count rates is acquired to measure a second depth of investigation. An apparent porosity is calculated using the timing measurements and the ratios of neutron count rates. The effect of a well casing on the calculated apparent porosity is determined in response to at least one of the ratio of neutron detector count rates and the timing measurement. A cement annulus is computed based on the ratios of neutron count rates and the timing measurement. A formation porosity is calculated by performing a correction to the apparent porosity for the casing and the cement annulus.

A method for formation logging includes acquiring measurements of neutron-induced signals having azimuthal information using a neutron tool; processing the measurements into a plurality of azimuthal sector data for each acquisition interval; and deriving a selected parameter from the plurality of azimuthal sector data. A logging tool includes a housing adapted to move in a borehole; a circuitry having memories for storing neutron-induced measurements; a neutron source disposed in the housing; and at least one detector bank disposed in the housing spaced apart from the neutron source, wherein each of the at least one detector bank comprises at least one detector disposed around a periphery of the housing such that the at least one detector is more sensitive to signals from an azimuthal direction, and wherein count rates detected by each of the at least one detector are separately stored in the memories.

Method and apparatus for extending a count rate capability of a detector array. The method includes receiving photons at a detector array, counting the photons that are above a first energy threshold using a first counter, counting the photons that are above a different second energy threshold using a second counter, and calculating a pile-up estimate using the photon counts from the first and second counters.

A method is for operation of a counting radiation detector, in particular of a counting X-ray detector, with improved linearity, in which each detector element of the counting radiation detector supplies counting pulses at counting rates as a function of a number of radiation quanta which occur per unit time during operation. In the method, the counting rates which are supplied from each detector element or from subsections of the detector element are converted via a functional relationship to actual counting rates or are multiplied by correction factors which are dependent on the magnitude of the counting rates. The correction factors are determined in advance for the respective detector element or for the subsections of it, and any discrepancy (which occurs as a result of a dead time of the detector element, for example) in the counting rates is corrected from the actual number of radiation quanta which arrive per unit time. The method allows the linearity of counting radiation detectors to be improved, particularly at high radiation intensities, so that the linearity condition for X-ray CT systems is also satisfied.

The invention discloses a Brillouin optical time domain reflectometer for single-photon detection based on an edged filter method, which comprises a narrow linewidth laser (1), a pulse modulator (2), a circulator (3), a sensing optical fiber (4), an optical fiber module (5), 3dB coupler (6), a linear edged filter (7), an InGaAs/InP SPAD (single-photon avalanche diode) detector group (8), a signal generator (9), a data processing module (10) and a pulse signal generator (11), wherein the InGaAs/InP SPAD detector group (8) includes two or three InGaAs/InP SPAD detectors. The InGaAs/InP SPAD detector group with a high counting rate and high sensitivity is used as a detection unit, Brillouin frequency shift information is acquired by the edged filter method, time correlation single-photon counting technology is adopted by the data processing module (10), limitations on the bandwidth and sensitivity of a traditional detector are broken through, spatial resolution and measuring precision of the reflectometer can be simultaneously improved, and temperature and strain are simultaneously sensed.

A system for on-line monitoring the stability of a scintillation detector, comprises means providing two beams of gamma rays from a subsidiary source which are distinguishable because of their time relationship from the primary source. The two beams are of similar energies but are oriented in different directions, with one directed into the scintillation detector and one acting as a reference beam and directed to a reference beam counter. The ratio of the detector-count rate for the timed events to the reference count rate is compared to provide an indication of any drift in the scintillation detector.

The invention discloses a high-speed superconducting nanowire single-photon detector (SNSPD) with a strong absorption structure and a preparation method of the high-speed SNSPD with the strong absorption structure. The SNSPD is capable of further improving the photon absorptivity of superconducting nanowires based on an incident medium with a high refractive index and an air cavity structure. Compared with the prior art and according to the high-speed SNSPD, under the condition that the nanowires are made of superconducting ultrathin membranes with the same material and the same thickness, nearly 100% of absorptivity can be realized through a lower duty ratio, and the difficulty of electron beams in the exposure steps is reduced greatly, thereby particularly being more beneficial to the preparation of the ultrathin nanowires; and meanwhile, by adopting a silicon on insulator (SOI) substrate, the high-quality growth of the superconducting ultrathin membranes can be ensured simultaneously without affecting the intrinsic quantum efficiency of the detector. In addition, under the condition that the large effective detection area is ensured equally, as the total length of the required nanowires is reduced obviously, the maximum counting rate of the detector can be improved, and the probability of occurring defects during preparation process is decreased notably.

A method and apparatus for determining and correcting the baseline of a continuously sampled signal for use in positron emission tomography. The method employs continuous signal sampling to determine the signal level at time t(0) so that an accurate determination of an integrated signal may be calculated, resulting in an accurate energy estimate for an ac-coupled, continuously-sampled signal at various count rates. The device includes a front-end electronics processing channel including primarily an analog CMOS ASIC, a bank of ADCs, an FPGA-based digital sequencer, and two RAMs. The processing electronics perform continuous digital integration of PMT signals to obtain normalized position and energy. Continuous baseline restoration (BLR) is used, wherein the baseline of the signal pulses are placed at mid-scale by continuously sampling the ADC, thus always making available the past history. A correction signal is generated for use in negative feedback control of the baseline.

The invention discloses a quantum secret key distribution privacy amplification method supporting large-scale dynamic changes. The method includes the steps of firstly, conducting initialization, wherein the optimal operation scale m of an FFT module is calculated according to the actual running parameters of a quantum secret key distribution system when the privacy amplification method is started, and the initialization scale is an FFT operation and inverse FFT operation module of m; secondly, normalizing data, wherein the final security secret key length r is calculated according to the detector counting rate Q mu of the quantum secret key distribution system, the quantum bit error rate E mu, the corrected weak security secret key length n and the security parameter s of the quantum secret key distribution system, and normalizing an initial secret key string and a Toeplitz matrix according to the parameter m, the parameter n and the parameter r; thirdly, conducting data operation, wherein the operation process of the Toeplitz matrix and the initial secret key string is operated through the FFT technology, the first r items of the calculation result are taken to form a result vector, namely, the final security secrete key. The method has the advantages of being high in flexibility, better in processing performance, and the like.

A method and counter for reducing the background counting rate in gas-filled alpha particle counters wherein the counter is constructed in such a manner as to exaggerate the differences in the features in preamplifier pulses generated by collecting the charges in ionization tracks produced by alpha particles emanating from different regions within the counter and then using pulse feature analysis to recognize these differences and so discriminate between different regions of emanation. Thus alpha particles emitted from the sample can then be counted while those emitted from the counter components can be rejected, resulting in very low background counting rates even from large samples. In one embodiment, a multi-wire ionization chamber, different electric fields are created in different regions of the counter and the resultant difference in electron velocities during charge collection allow alpha particles from the sample and counter backwall to be distinguished. In a second embodiment, a parallel-plate ionization chamber, the counter dimensions are adjusted so that charge collection times are much longer for ionization tracks caused by sample source alpha particles than for those caused by anode source alpha particles. In both embodiments a guard electrode can be placed about the anode's perimeter and secondary pulse feature analysis performed on signal pulses output from a preamplifier attached to this guard electrode to further identify and reject alpha particles emanating from the counter's sidewalls in order to further lower the counter's background.

Method and system for analyzing electrical pulses contained in a pulse train signal representative of the interaction of x-ray bursts with a nuclear detector configured for subsurface disposal. The pulse train signal is sampled to form a digitized signal. The total energy deposited at the detector during an x-ray burst is determined from the digitized signal, and a count rate of x-ray pulses from the burst is determined. A subsurface parameter is determined using the total energy deposit.

An embodiment of the invention discloses a method and a device for normal correction of scanning data in imaging equipment. The method includes scanning a model and acquiring a plurality of groups of correction data; optionally combining the groups of correction data to obtain correction data combinations corresponding to different counting rates, thus obtaining correction data corresponding to the different counting rates; calculating normal correction factors under the different counting rates according to the correction data corresponding to the different counting rates; and correcting scanning data different in counting rate in the imaging equipment through the normal correction factors under the different counting rates. The method and the device according to the embodiment have the advantages that acquisition time of correction data can be shortened and the problem of image artifacts caused by mismatch of the counting rates is also avoided.

The invention discloses a novel system and method of measuring concentration of radon in water. The novel system of measuring concentration of radon in water includes successively connected first Gamma detector, first linear amplifier, first single-channel pulse-height analyzer, first delay shaping circuit and first scaler, and successively connected second Gamma detector, second linear amplifier,second single-channel pulse-height analyzer, second delay shaping circuit and second scaler, wherein the output terminal of the first delay shaping circuit and the output terminal of the second delayshaping circuit are connected to the input terminal of a coincidence circuit; the coincidence output terminal of the coincidence circuit is connected with a third scaler; the novel system of measuring concentration of radon in water also includes a calculation module which is used for calculating the activity concentration C<222><Rn>: C<222><Rn>=n<Gamma Gamma 1> - n) / V<Elipson> <Gamma Gamma>of 222Rn in a sample to be measured, wherein n<Gamma Gamma 1> is the counting rate of the third scaler during the process of measuring the sample to be measured; n is the background counting rateof the third scaler; V is the volume of the sample to be measured; and Epsilon <Gamma Gamma> is the detection efficiency of a coincidence channel. The novel system and method of measuring concentration of radon in water can quickly reduce the measurement background and can achieve the effect of quickly and accurately measuring the concentration of radon in water.