Counting Rate Meter Research Articles

A simple and low-cost directional detection technique for radiation source localization for nuclear security applications

One of the goals in the field of nuclear security is to prevent the misuse and loss of nuclear or other radiological materials. If lost or stolen, radioactive materials could be located and secured using radiation detectors like count rate meters or imaging systems. However, such detectors may not allow for the swift localization of lost sources or may be cost prohibitive in many measurement scenarios. A simple, low-cost, directional radiation detector that is capable of quickly “pointing” towards the nearest radiation source is sought for source search scenarios. Such a detector can be realized using a plastic scintillator couple on each end to photo-multiplier tubes, as shown in this work. The event-by-event position of scintillation in this study is approximated by averaging the amount of light arriving at each of the photomultiplier tubes during coincidence counting. The detector system is then rotated so that the approximated scintillation positions within the detector volume can be determined in other spatial dimensions. A guess vector generated by comparing light ratio skewness produced by the detector in orthogonal orientations points in the direction of a nearby radiation source. An MCNPX-PoliMi model was used to guide the design of such a detector and validate the guess-vector technique. A prototype system using a cube of an EJ-204 plastic scintillator and two photomultiplier tubes was constructed and a correlation between azimuthal source position and detector response was established. For measurements of tens of thousands of counts, the detector prototype generates guess vectors that can identify source position to within 5° uncertainty. The detector prototype can determine the general direction of a nearby source to within 45° uncertainty using 1000 total counts.

Markedness-Based Analysis of Englyn Meter

This research aims to examine the Englyn meter in the poetry of Celtic language (Medieval Welsh) that requires the poetic texts to conform to an abstract prosodic template. This counting meter regulates the phonological constituency on the same metric level of the prosodic hierarchy rather than on the metrical hierarchy in verse (the line). In the main types of Englyn meters, Englyn milwr and Englyn penfyr, phonological units of each line are constrained with a certain number of syllables and rhyme with the final syllable of most lines. This research offers a markedness-based analysis that generates the well-formedness meter of Celtic language Welsh poetry. The Optimality Theoretical analysis derives the constraint on the phonological constituency over a certain metric level of the prosodic hierarchy (the line) with markedness constraints. Further coping constraints that are normally used for reduplication are needed to account for the rhyme of the final syllable in Englyn meter. The analysis offered supports the Development hypothesis, which is fundamental to generative metrics indicating that meter is evidently related to general language phonology. These results could help analyse other counting meters with restricted phonological constituency.

Teaching musical meter to school-age students through the Ski-Hill graph

This thesis, Teaching Musical Meter to School-Age Students Through the Ski-Hill Graph, aims to demonstrate the “pedagogability” of modern meter theory, that is, that new scholarship on meter can translate into a coherent and practically implementable instructional curriculum, with various advantages for school-age students. The curriculum model developed in the thesis is derived from Richard Cohn’s work on and approaches to meter theory, the first comprehensive theory and approach to teaching and learning meter which focuses on the embodied psychoacoustic experience of sound and graphic representations of meter through mathematical music theory rather than notation-based understandings. The materials set out in the thesis demonstrate ways students might be taught to articulate their experience of meter. A unified approach, it incorporates Cohn’s ski-hill graph and other instruments of mathematical music theory such as the SkiHill app (Milne, 2018) and XronoBeat app (Milne, 2019) numbering for counting meter, cyclic graphs, and beat-class theory. The thesis demonstrates how traditional Western music theory has evolved due largely to non-Western influences to now possess the capacity for analyzing music from around the world. In addition, the outcomes it anticipates is a deeper engagement with music in classroom settings.

The research of fibroblasts from human hypertrophic scar showing a mesenchymal stem cell phenotype and multilineage differentiation potentialities

To explore the CD phenotypic, protein expression and pluripotent differentiation of human hypertrophic scar fibroblasts cultured in vitro, so as to study the mechanisms of scar formation. Fibroblasts were isolated and cultured from human hypertrophic scar of 3 cases. The cells morphology was observed by inverted microscope, and the growing state of the third passage was detected by the cell counting meter of Vi-CELL. The cell surface markers CD105, CD14, CD73, CD34, CD44, CD45 and CD90 were identified by flow cytometry. The expression of CK19, Oct-4, Nanog and vimentin was detected by immunocytochemistry, and the expression of alpha-smooth muscle actin(alpha-SMA) was tested by immunofluorescence. The differentiated potential of fibroblasts of the third passage into adipogenic, osteogenic and chondrogenic lineages was assayed. The primary passage fibroblasts showed the shape of spindle shaped or irregular polygon with a radiated or circinate of growing arrangement. The growth curve showed the cells growth was slow on the first and second day, and quick during the third to fifth day, which reached platform stage on the sixth or seventh day. The fibroblasts highly expressed mesenchymal stem cell surface markers-CD73, CD105, CD44, CD90, but not expressed hematopoietic stem cell surface markers-CD14, CD34, CD45 by flow cytometry. And positive expression of vimentin, Oct-4 and negative expression of CK19 were detected by Immunocytochemistry. Positive expression of alpha-SMA was also detected by immunofluorescence. Multidirectional differentiation induction indicated that the third passage cells could differentiate into adipogenic, osteogenic and chondrogenic lineages. Human hypertrophic scar-derived fibroblasts show the biologic characteristics of mesenchymal stem cells, which may play an important role in wound healing and hypertrophic scar formation.

99mTc-Novobiocin: a~novel radiotracer for infection imaging

Abstract The radiosynthesis of 99mTc-Novobiocin (99mTc-NBN) complex and its suitability as a radiotracer for infection imaging was assessed. The radiochemical purity (RCP) of the 99mTc-NBN complex was determined using radio-TLC and radioactive HPLC and biodistribution was studied in artificially infected (A.I.) rats and rabbit, using single well gamma counter (SWGRC) interface with scalar count rate meter (SCRM) and Gamma Camera (γ-CM). The maximum RCP observed for the preparation having 2 mg of NBN, 111 MBq of sodium pertechnetate (Na99mTcO4) and 125 μL of SnF2 (1 μg/μL in 0.01 N HCl) at a pH 5.6 was 98.97±0.40% and remained stable >90% up to 120 min. The activity of the 99mTc-NBN in the infected muscle (TI) was significantly increased from 6.50±0.15 to 19.00±0.17% and decreased in the inflamed muscle (TII), normal muscle (NT), blood, liver, spleen, stomach and intestine within 120 min. The TI/NT and TII/NT ratios were 7.60±1.08 and 1.60±1.14. The Whole Body Static (WBS) images of A.I. rabbit were obtained at 30, 40, 50 and 60 min after the I.V. administration of 111 MBq of 99mTc-NBN to the A.I. rabbit. The stability in saline and serum, higher TI/NT, lower TII/NT ratios and WBS images confirmed the feasibility of the 99mTc-NBN complex as an infection imaging agent.

Realization of a digital rate meter as an IIR digital filter by implementing an optimized signal processing algorithm

By applying the well known dualism: mean count rate - mean time between successive pulses - the equivalence between an IIR digital filter and a preset count digital rate meter has been demonstrated. By using a bank of four second order IIR filters and an optimized automated algorithm for filter selection, a practical realization of a preset count rate meter giving good tradeoff between statistical fluctuations and speed of response, particularly at low count rates such as background monitoring, is presented. The presented solution is suitable for designing portable count rate meters. The designed prototype is capable of operating up to 3600 pulses per second with an accuracy of over 4% in steady-state and response times of 1 second for the rising edge and 2 seconds for the falling edge of the mean count rate step-change.

Techniques employed for detection of hot particles in the marine environment

During the decommissioning of the Maine Yankee nuclear plant, several methods weredeveloped and employed to survey for hot particles in the marine environmentsurrounding the site. The methods used and the sensitivities achieved in the search forenvironmentally dispersed particles during the various decommissioning activitiesperformed are described in detail. Surveys were performed on dry soil, exposed marinesediment and submerged marine sediment. Survey techniques ranged from the use ofthe basic NaI detector coupled to a count rate meter to an intrinsic germaniumdetector deployed in a submarine housing coupled to a multi-channel analyser.The initial surveys consisted of collecting samples of marine sediment, spreading them out over a1 m2 surface in a thin layer, and scanning the deposited sediment by hand using a 5 cm by 5 cmNaI detector coupled to a standard count rate meter. This technique was later replaced bywalkover scans with the 5 cm by 5 cm NaI detector moved in a serpentine pattern overthe sediment surface. By coupling the detector to a ‘smart meter’, an alarm setpoint could be used to alert the surveyor to the presence of a particle within theinstrument’s field of view. A similar technique, with the detector mounted in awatertight housing secured to the end of a pole, was also employed to scan underwaterlocations. The most sensitive method developed for performing underwater surveyswas the use of the intrinsic germanium detector placed in a submarine housing.Detailed descriptions of the methods employed and the results obtained are presented. Thiswork demonstrates that there are several approaches to surveying for discreteparticles in the marine environment and the relative merits of each are considered.

Count rate meter with a time constant using adaptive digital signal processing

Two methods developed to improve the classical time constant count rate meters by using the adaptive signal-processing tools are presented. An optimized detection algorithm that senses the change of the mean count rate was implemented in both methods. Three different types of low-pass filters of various structures with adaptive parameters to implement the control of the mean count rate error by suppressing the fluctuations in a controllable way were considered, and one of them was implemented in both methods. An adaptation algorithm for time constant interval calculation was executed after the low-pass filter was devised and implemented in the first method. This adaptation algorithm makes it possible to obtain shorter time constant intervals for higher stationary mean count rates. The adaptation algorithm for time constant interval calculation executed before the low-pass filter was devised and implemented in the second method. This adaptation algorithm enables sensing of the rapid change of the mean count rate before the fluctuations suppression is carried out. Some parameters were fixed to their optimum values after appropriate optimization procedures had been performed. The implemented low-pass filter has variable number of stationary coefficients depending on the specified error and the mean count rate. It implements the control of the mean count rate error by suppressing the fluctuations in a controllable way. The simulated and realized methods, using the developed algorithms, guarantee: a response time not in excess of 2 s for a mean count rate higher than 2 counts/s and a controllable mean count rate error in the range of 4–10%.

Some practical realizations of preset time count rate meters using optimized adaptive digital signal-processing solutions

Two optimized adaptive digital signal processors were developed to implement the preset time count rate meters. The first processor improves stationary characteristics of the count rate meter by implementing the control of the error of the mean count rate when the changes of the mean count rate are only due to its stochastic nature. The second processor is focused on dynamic characteristics. Its time response is made adaptive to the changes of the mean count rate which are due to increased or decreased radiation levels. The change of the mean count rate is sensed by a specially devised detection algorithm. Three mean count rate meters, based on the developed adaptive digital signal processors, were realized and were used for experimental validation of proposed adaptive digital signal processors. The experimental results, conducted without and with radioisotope for the specified errors of 10% and 5%, showed to agree well with theoretical predictions.

NORM Contamination—Now You See It, Now You Don’t

Contamination from naturally occurring radioactive material on the inside of piping or tanks in refineries can usually be easily detected from the outside by external gamma measurements with simple count rate meters or more complicated gamma spectroscopy instruments. Usually, such contamination is from radium in equilibrium with its progeny. A number of different gamma rays are emitted by this mix. However, due to certain processes or circumstances, a significant amount of NORM can be present without the characteristic gamma signature of radium and its progeny. The process of cracking low molecular weight hydrocarbon gases from crude oil allows radon through but leaves radium behind. The radon enters the process piping and decays, depositing its short-lived decay products or progeny. When the short-lived progeny decay, all that is left are alpha and beta emitters. When this occurs, measurements taken on the outside of piping indicate no elevated levels of gamma radiation; however, elevated levels of alpha and beta radiation can be detected on the inside of the piping. 210Pb is usually the only gamma emitter detected on the inside of the piping and, its gamma ray energy is such that little if any penetrates the walls of the piping. Since one of the release criterion for piping material is an external dose rate of less than 50 microR h(-1), it is possible that a survey from the outside of the piping can be negative when, in fact, thee can be appreciable contamination on the inside of the piping.

SU‐FF‐T‐23: Comparison of Chest Radiographs, Fluoroscopy and Seed‐Migration Detector for the Detection of Embolized Seeds to the Lung

Purpose: To evaluate the efficacy of a seed‐migration detector and to compare its performance to fluoroscopy and to the postoperative chest radiographs generally recommended. Method and Materials: A low energy gamma scintillation survey meter, used together with a count rate meter, was converted to a seed‐migration detector. The detector was used to perform a chest evaluation on 155 patients (8717 seeds) at their first postoperative visit. When the detector showed activity around a patient s chest, it was confirmed by taking an antero‐posterior chest radiograph and by looking at the region with fluoroscopy. Results: 33 patients (21.3%) present at least one embolized seed. That is a 0.47% seed migration rate (41/8717). 37 (90%) of the seeds were visible under fluoroscopy and 28 (68%) appeared on x‐rays. Rapid movement of the seeds, due to breathing or to a location close to the heart or the diaphragm, makes nine seeds to be visible with fluoroscopy but not on the radiograph. Moreover, four seeds were not visible with fluoroscopy neither with radiograph. In comparison to the seed‐migration detector, detection based on fluoroscopy would have led to four false‐negative detections (out of 33 or 12.1%) while the radiograph would have resulted in thirteen (out of 33) false‐negative detections or 39.4%. Finally, standard chest x‐ray would have required a survey, and extra radiation dose to lung, to 100% of the patients rather than the 21.3% who needed it in this study. Conclusion: Because of the high false‐negative rate and the superior efficacy of a scintillator‐based seed‐migration detector, the usual recommendation to perform chest radiographs should be revised. X‐rays should remain for documentation purposes of positive cases only. Our clinical experience also allowed us to conclude that the detector is convenient, cost‐effective and non‐invasive, meaning that it does not require any additional radiation to the patient.

Practical realizations of optimized adaptive digital signal processing solutions implemented in preset time count rate meters

Two optimized adaptive digital signal processors were implemented to the preset time count rate meters. Three mean count rate meters, based on the developed adaptive digital signal processors, were realized and were used for experimental validation of proposed adaptive digital signal processors. The experimental results, conducted without and with radioisotope for the specified errors of 10% and 5%, showed to agree well with theoretical predictions.

Experimental verification of preset time count rate meters based on adaptive digital signal processing algorithms

Experimental verifications of two optimized adaptive digital signal processing algorithms implemented in two pre set time count rate meters were per formed ac cording to appropriate standards. The random pulse generator realized using a personal computer, was used as an artificial radiation source for preliminary system tests and performance evaluations of the pro posed algorithms. Then measurement results for background radiation levels were obtained. Finally, measurements with a natural radiation source radioisotope 90Sr-90Y, were carried out. Measurement results, con ducted without and with radio isotopes for the specified errors of 10% and 5% showed to agree well with theoretical predictions.

Preset time count rate meter using adaptive digital signal processing

Two presented methods were developed to improve classical preset time count rate meters by using adapt able signal processing tools. An optimized detection algorithm that senses the change of mean count rate was implemented in both methods. Three low-pass filters of various structures with adaptable parameters to implement the control of the mean count rate error by suppressing the fluctuations in a controllable way, were considered and one of them implemented in both methods. An adaptation algorithm for preset time interval calculation executed after the low-pass filter was devised and implemented in the first method. This adaptation algorithm makes it possible to obtain shorter preset time intervals for higher stationary mean count rate. The adaptation algorithm for preset time interval calculation executed before the low-pass filter was devised and implemented in the second method. That adaptation algorithm enables sensing of a rapid change of the mean count rate before fluctuations suppression is carried out. Some parameters were fixed to their optimum values after appropriate optimization procedure. Low-pass filters have variable number of stationary coefficients depending on the specified error and the mean count rate. They implement control of the mean count rate error by suppressing fluctuations in a controllable way. The simulated and realized methods, using the developed algorithms, guarantee that the response time shall not exceed 2 s for the mean count rate higher than 2 s-1 and that controllable mean count rate error shall be within the range of ?4% to ?10%.

The error estimate for the modified preset count ratemeter algorithm

Analogously to the traditional preset count rate meter algorithm, the error estimate of the modified preset count ratemeter algorithm has been defined as the range around measured mean count rate containing 2/3 of the measurement results. The coefficients determining this range have been calculated for a set of values of the modification parameter (m) and preset count (NT). The calculations cover the ranges of these parameters which are of practical interest (m 0 25 1 5 NT 12 150). By applying the piecewise-linear interpolation scheme it is possible to calculate measurement error for any pair m NT within the ranges of these parameters covered by the present calculations.

Stability of currently used cytometers facilitates the identification of pipetting errors and their volumetric operation: “Time” can tell all

M. Bergeron, G. Lustyik, S. Phaneuf, T. Ding, J. K. A. Nicholson, G. Janossy, H. Shapiro, D. Barnett, and F. Mandy* Health Canada, Ottawa, Ontario, Canada Soft Flow, Inc., Minneapolis, Minnesota National Center for Infectious Diseases, Atlanta, Georgia Royal Free and University College Medical School, London, United Kingdom West Newton, Massachusetts Royal Hallamshire Hospital, Sheffield, United Kingdom

The optimum dynamic parameters of digital rate meter algorithms

The definition of the “Quality,” Q, of a count-rate meter algorithm is introduced as the reciprocal of the algorithm’s (τ×ε) product, where τ is the response time of the algorithm to a sudden change in the average count rate and where ε is the fractional standard deviation of the steady-state measurement of a constant average count-rate pulse stream. Analytical expressions for τ and ε of digital rate meter algorithms are used to calculate maximum values of Q for both linear and exponential algorithms. The values of the basic algorithm parameters necessary to achieve these minimum (τ×ε) products are derived for both algorithms. The use of these values results in algorithms that have relatively short response times and, simultaneously, relatively small steady-state errors.

計数率計をもつ放射線リレーによる位置制御系の最適設計

Optimum design of the position control system using radiation counting rate meter is presented in this paper.As the controlled object (water level or edge of plate) covers the incident window of radiation detector from one side to the other with constant speed, the amount of incident radiation varies. This radiation is measured by a counting rate meter and at the time when the output of rate meter reaches the threshold value, a relay acts and stops the motion of controlled object.In a previous paper, the auther gave some expressions for calculating statistical characteristics of output of rate meter, considering saturation of rate meter.By these expressions mean value and standard deviation of the stopping position of controlled object can be obtained.From these results it is proved that the optimum time constant of the rate meter is the one which stops the controlled object at the position where incident window has just closed, and also that the extent of saturation of rate meter has no effect on standard deviation of stopping position.The necessary total incident counts while the controlled object gose across window can be also obtained, for getting a given standard deviation of stopping position.Compare this control system with a system using radiation scaler (digital measurement), this system is favorable in case of high moving speed of controlled object, because the necessary total incident counts is less than scaler type system.

Slim Hole Logging and Analysis for Uranium Exploration

Significant improvements have been made in uranium logging equipment and analysis techniques. Logging systems now provide geological, geophysical, and geochemical data from routine measurements. Through computer analysis, these systems also can determine porosity, density, permeability, lithology, formation-water resistivity, and thermal and mechanical properties. Introduction Deeper targets for uranium exploration warrant more complete logging systems than those used previously. Such systems can produce adequate data for a geologic understanding of the ore deposition processes with fewer drill holes. As the formation depth increases, data extrapolated from surface outcrops become less reliable and make log-derived data more important. An alternative to a complete logging package is extensive coring of ore-bearing and related formations, but this is expensive and time consuming. We are using reasonably sophisticated logging systems that provide data for geologic models, which are used to understand the sedimentary environment, groundwater, and other physical and chemical properties of uranium deposition. These models, based largely on log-derived data, are important when designing infill drilling for exploration, evaluation, or production. Uranium log interpretation is simplified somewhat by short drilling times that restrict invasion and by lack of hydrocarbons that complicate fluid properties. However, less-sophisticated small-diameter downhole tools can have the opposite effect. Logging System The digital logging systems that we use have been designed for relatively simple operation. Analog records are produced during logging to verify equipment operation and allow operator adjustments if necessary. For most logging tools, digital data are generated uphole from a depth encoder, two count-rate meters, and four 4.5-digit volt meters. Signals are recorded from all of these devices at operator-selectable digitization intervals. Recordings are made with cassette tape decks using a 1,200-baud transfer rate. With this recording rate, logging speed is limited by the downhole instruments themselves. Up to 2,000 ft (600 m) of multiplexed logs can be recorded on one side of a cassette. Each truck is designed to run at least 12 separate downhole tools with minimal operator intervention. At present, three sondes are used routinely and several others are used on an experimental basis. These include a gamma-ray log that uses a 0.75×1.25 in. (1.91×3.18 cm) Nal crystal with downhole scaling in areas where count rates are high. This tool also generates 16- and 64-in. (41- and 163-cm) normal calibrated resistivity curves. A single-point resistivity curve can be recorded for correlation with older uranium logs. Also, a spontaneous potential (SP) curve is measured but is difficult to interpret in mineral logging since this potential is the sum of several variable potentials including chemical, membrane, and filtration.

放射線計数率計出力のしきい値到達のシミュレーション

放射線計数率計出力のしきい値到達のシミュレーション