Multichannel Pulse Height Analyzer Research Articles

The quantitative effect of electronic noise on the accuracy of timing signals from a detector

Analysed in detail is the problem of the time distribution of pulses from a perfect trigger circuit (leading-edge, constant-fraction or other) fed by signal pulses of arbitrary but constant shape superposed on electronic noise. Evaluated for two particular cases are the full shape of the time distribution, its height, its width and the probability of missing an event. Methods are given for easily measuring all relevant parameters, so there are no adjustable parameters. For a linear, zero-crossing signal the noise results in an amplitude-dependent walk of ≥0.2 of the time required for the signal to change by a voltage equal to the standard deviation of the noise. For a rectangular signal pulse, the time distribution is a delta-function followed by an exponential, and the probability of missing it is evaluated. Also calculated is the complete noise spectrum as observed in a multichannel pulse-height analyser.

Pulse method for measuring sound absorption in the kilohertz range

Solid-dielectric capacitance transducers, 25.4 cm in diameter, have been constructed and used to generate and detect pulses of sound waves in the frequency range from 4 to 200 kHz. The waves are propagated inside an aluminum tube, 25.4 cm i.d. and 4.5 m long. One of the transducers generates the sound pulses and can be moved axially along the tube; the second serves as a microphone, detecting the sound pulse and reflecting it at one end of the tube. The transducers are made by stretching metalized Mylar across a polished backing plate. Effects of diffraction, transducer nonalignment, and transverse modes within the tube are discussed. The sound absorption is obtained by the measurement of either the attenuation of the first pulse or the increase in the echo decay rate with distance. Pulse heights are measured with a multichannel pulse height analyzer and an on-line computer. The system has been used to measure sound absorption in humid air. [Work supported by NASA-Lewis Research Center.]

A peak integrator suitable for use with a multichannel pulse height analyser

A description is given of a peak integrator which sums the total ccount in a group of channels in a multichannel analyser. The lowest channel in the group is set on the analyser and the number of channels to be summed is set on the unit itself. The sum is displayed on numerical indicators. The unit is built in a single width NIM module, and all inputs and outputs are TTL compatible.

ChemInform Abstract: NEUTRON‐ACTIVATION ANALYSIS OF SELENIUM, OSMIUM AND RUTHENIUM IN ROCKS, SEDIMENTS AND BIOLOGICAL MATERIALS BY SUCCESSIVE DISTILLATIONS WITH THREE KINDS OF STRONG PHOSPHORIC ACID REAGENTS

Chemischer InformationsdienstVolume 6, Issue 48 Preparative Inorganic Chemistry ChemInform Abstract: NEUTRON-ACTIVATION ANALYSIS OF SELENIUM, OSMIUM AND RUTHENIUM IN ROCKS, SEDIMENTS AND BIOLOGICAL MATERIALS BY SUCCESSIVE DISTILLATIONS WITH THREE KINDS OF STRONG PHOSPHORIC ACID REAGENTS KIKUO TERADA, KIKUO TERADASearch for more papers by this authorKEN MATSUMOTO, KEN MATSUMOTOSearch for more papers by this authorTOSHIYASU KIBA, TOSHIYASU KIBASearch for more papers by this author KIKUO TERADA, KIKUO TERADASearch for more papers by this authorKEN MATSUMOTO, KEN MATSUMOTOSearch for more papers by this authorTOSHIYASU KIBA, TOSHIYASU KIBASearch for more papers by this author First published: December 2, 1975 https://doi.org/10.1002/chin.197548447AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume6, Issue48December 2, 1975 RelatedInformation

An Ion Counting Method with Multichannel Pulse Height Analyser for High Sensitive Mass Spectrometry

A newly developed ion counting method in mass spectrometry is described. This method makes use of analog switch, so as to make the output pulse height from the secondary electron multiplier linear in (m/e)1/2 of the ions. When fed to a multichannel pulse height analyser (MC-PHA), these output pulses produce a histogram which directly represents the mass spectrum. The new method makes possible a rapid scanning of the magnetic field in a mass-spectrometer. In order to overcome problems of counting loss of ions, which is caused mainly by MCPHA, it is required to change the accumulation rate of pulses in MCPHA especially for the most abundant isotopes. For this purpose, we designed a “window sensitivity attenuator", in which the incoming rate of ions to the electron multiplier is converted into its 1/2n by using a series of binary counters. The new counting method was applied to the isotopic measurement on magnesium with samples of inclusions of the Allende Meteorite, and the results are presented.

Neutron-activation Analysis of Selenium, Osmium and Ruthenium in Rocks, Sediments and Biological Materials by Successive Distillations with Three Kinds of Strong Phosphoric Acid Reagents

Abstract A new separation scheme is presented for the neutron-activation analysis of selenium, osmium and ruthenium in solid samples such as rocks, sediments and biological materials. A neutron-irradiated sample accompanying the carriers of the three elements was heated with the bromide-SPA reagent to 250°C, whereupon selenium came out as gaseous selenium tetrabromide. The second distillation was performed by heating the residual sample with Ce(IV)-SPA reagent till 285°C to separate osmium as osmium tetroxide gas. The last distillation of ruthenium as ruthenium tetroxide followed under heating the residue with the Cr(VI)-SPA reagent till 245°C. Each distillate was absorbed in an appropriate absorbing solution from which selenium metal, osmium thiourea chromithiocyanato complex, and ruthenium metal were respectively recovered and they were submitted to γ-counting by means of a Ge(Li) detector coupled with a multi-channel pulse height analyzer. The chemical recoveries of the added carriers were found to be about 80% for selenium and above 90% for osmium and ruthenium.

Improved Measurement of Erythrocyte Volume Distribution by Aperture-Counter Signal Analysis

In aperture counters, particles in fluid suspension flow through a small orifice or aperture, causing a change in the electrical resistance of the aperture. This change is sensed by an external electronic circuit and translated into a voltage pulse, the signal height of which is proportional to the volume of the particle in the aperture. These signal pulses are collated into a spectrum of pulse heights by a multichannel pulse-height analyzer. The channel number (voltage increment) spectrum is proportional to the volume distribution of the particles sensed. A problem is that pulse height not only depends on cell volume, but also on the orientation and shape of the particle sensed and the current density along the path taken by the particle through the aperture. Uneven current density exists, primarily at the aperture entrance and exit, close to the wall. Orientation and shape of particles are altered near the wall by the unbalanced shear forces there. Toward the center of the aperture, the shear forces act so as not to induce continuous change in the orientation of the particles sensed. Thus introduction into the pulse-height spectrum of pulses that do not show a good proportionality to volume is primarily caused by particles that are traveling near the aperture wall. Residence time in the aperture for a particle traveling near the wall will be longer than that for a particle traveling down the center of the aperture, because of the smaller fluid velocity near the wall. Duration of the signal pulse created by a particle traveling near the wall will be correspondingly greater. We discuss an electronic filter to remove from the pulse-height spectrum those pulses that appear to result from particles traveling near the wall and the effect of the filter on the measured signal height and hence the volume distribution of erythrocytes. Use of this technique to characterize erythrocytes by volume distribution is described.

The Discharge-Repetition Rate in Cavities in Epoxy Resin, Polyethylene, and Mica under Alternating Voltage Conditions

An investigation into the repetition rate and magnitude of internal discharges in artificial cavities in epoxy resin, polyethylene, and mica, using a multichannel pulse height analyzer is described. The effect of time of voltage application, cavity dimensions, and location, and opening the cavity or ventilating it in air and nitrogen has been studied. The results indicate that it is the discharge quantity rather than the discharge energy measured externally in the largest pulse that is important. It is suggested that in order to correlate discharge damage with discharge activity, it is essential to measure continuously both discharge magnitudes and repetition rates.

Corona pulse probability density function measurements on primary distribution power cables

A multichannel pulse-height analyzer has been used to carry out statistical analyses of the corona pulse density patterns of EPR and XLPE insulated distribution cables. The corona pulse probability density functions obtained on these cables were studied as a function of applied voltage and time. The practical implications of the test results are discussed in the light of present corona level specifications, cable insulation geometry and type as well as insulation system life.

塩化メチル水銀および亜セレン酸ナトリウム投与マウスにおける水銀とセレンの生体内分布

It is widely known that the causative substance of “Minamata disease” was methylmercurials concentrated in the fishes and shellfishes. It has been also reported that the organs of the patients as well as those of cats, fishes and shellfishes which suffered from the same disease contained high concentrations of selenium in addition to methylmercurials.But the investigation of the modifying effect of selenium compounds on the toxicity of methyl-mercurials is not necessarily ample and the study on the distribution of methylmercurials and selenium compounds in the body exposed to them simultaneously is almost scanty. The present paper describes the distribution of radioactive mercury (203Hg) and selenium (75Se) in mice after the simultaneous exposure to methylmercuric chloride and sodium selenite.In order to determine radioactive mercury and selenium, the simultaneous-discriminative determination method using a Ge (Li) solid state detector with a multi-channel pulse height analyzer was established and used.Since the acute lethal dose of sodium selenite in mice have not yet been known, the lethal toxicity test was carried out in advance to fix the standard for the dose used in the present study. I. Lethal effective dose 50% (LD 50) of sodium selenite in mice.Thirty five mice (ICR-JCL strain, male, 12w., mean ±SE of body weight=37.0 ±2.3g) were equally divided into five groups. To each group of mice a single respective dose of 0, 3.0, 4.8, 7.7 and 12.3mg Se/kg of sodium selenite was injected subcutaneously. Observation period was one week. As a result the approximate value of LD 50 was 6 mg Se/kg and the dose-response curve seemed to rise sharply around LD 50.II. Simultaneous-discriminative determination method of radioactive mercury (203Hg) and selenium (75Se).The Ge (Li) solid state detector and the pulse height analyzer with 1024 channels were used for determining the radioactivity of 203Hg (γ : 0.279 MeV) and 75Se (γ : 0.280 and 0.265 MeV). The calibration curve of energy vs. channels, the relationship between the sample size and the cpm, the limits of determination and the percentage of the cpm of the γ-ray (0.280 MeV) to that of the γ-ray (0.265 MeV) of 75Se were examined. The method of calculation of the radioactivity from the record was also described.Consequently the samples of which both the radioactivity itself and the percentage of the cpm of the γ-ray (0.280 MeV) to that of the γ-ray (0.265 MeV) of 75Se showed the constant values with some variance and of which the sample size (cross section) was almost the same as that of the tissue used for the present experiment could be measured and gave us reasonable data. III. Distribution of 203Hg and 75Se in the body.Forty five mice (ICR-JCL strain, male, 11 w., mean ±SE of body weight=32.1±1.9g) were equally divided into three groups which were treated with methylmercuric chloride alone, both methylmercuric chloride and sodium selenite, and sodium selenite alone, respectively. To each group of mice labeled compounds of methylmercuric chloride (CH3203HgCl, 125 μCi/1mg Hg/1kg of body weight) and/or sodium selenite (Na275SeO3, 132 μCi/0.5mg Se/1kg of body weight) were injected subcutaneously. At the specified time mice were killed after collecting blood by heart puncture followed by removing the small intestines including their contents, brain, liver and kidneys. Radioactivity of mercury and selenium was measured according to the method described above.The results and discussion are as follows : 1. In regard to the concentration and the elimination rate of mercurials in the liver, kidneys, small intestines and blood, no obvious difference was detected between the group treated with the two compounds and the

Effective elimination of the Compton component in amorphous scattering by experimental means

In the X-ray scattering from amorphous materials, the coherent-peak profile overlapped with part of the Compton distribution can be directly obtained at each (sin θ)/λ, with an energy-dispersive detector and multichannel pulse-height analyzer combination adapted to an X-ray diffractometer. For the `effective' elimination of the Compton component it is useful for one to pick out the half-profile, Ibh, on the higher-energy side of the peak maximum of the incident beam (in an energy scan at fixed scattering angle). On the assumption that the Compton scattering occurs within a range of energy lower than that of the incident radiation, the Compton contribution to Ibh is negligibly small compared to the strong coherent intensity and Ibh can be taken to represent the coherent intensity. As an illustration, the method is applied to the scattering from amorphous selenium. The resulting radial distribution function is in good agreement with the carefully examined result of using a crystal monochromator in the diffracted beam.

Carbon/Oxygen (C/O) Logging Instrumentation

Abstract An instrument system has been developed for field measurement of the relative carbon content of reservoir rocks. Gamma rays produced by inelastic scattering of 14-MeV neutrons are detected and analyzed in a sophisticated scintillation spectrometer system adapted for routine commercial well logging. A pulsed-neutron source similar to those in commercial use for other nuclear logs is employed. A van de Graaff generator provides the accelerating voltage to initiate the deuterium-tritium reaction, which produces the neutrons in a specially designed ion acceleration tube. Pulses from the radiation detector are transmitted to the surface oiler a conventional seven-conductor logging cable without degrading the spectrum. The log is available on a limited commercial basis and is recommended for identifying oil-saturated zones in cased wells where formation water is too fresh for reliable application of the Neutron Lifetime Log. Introduction A practical method of identifying the element carbon and assaying its abundance in cased-off formations has long been sought as a means for finding oil in situ. Since oil is largely composed of carbon, a measurement of carbon concentration is a direct method of evaluating the oil content of a formation. A nuclear logging technique whereby such a measurement can be made has been known since about 1950, and much effort has been expended in many laboratories to develop a system that could be used commercially to evaluate the hydrocarbon saturation of potentially productive reservoir rocks. Such a system is now available and has been field tested with gratifying results. This paper concerns the general features of the system, which is presently in commercial use on a limited basis. FIELD INSTRUMENTATION The subsurface instrument is 3-5/8 in. in diameter by 14 ft long. It is rated for a maximum temperature of 350 degrees F and pressure of 15,000 psi. It is equipped with a collar locator to enhance the accuracy of depth correlation and it can log to 7 ft above bottom. One or more neutron-type curves can also be run to assist in correlation with available open- or cased-hole logs. The instrument operates on a standard seven-conductor logging line, and curves are recorded on a conventional strip-chart recorder. Measurement of carbon-to-oxygen ratio can be recorded as a continuous curve vs borehole depth when desired. In usual practice, a continuous curve is of little value because statistical fluctuations in the measurement tend to obscure the true character of me log. For best results, stationary measurements are made at preselected points of interest. These are made for a time interval of 1 to 10 minutes each, depending on the accuracy desired and the number of zones to be surveyed in the time available for the logging operations. Typically, a logging operation comprises a continuous "correlation curve" over all zones of interest plus a station measurement at each of 10 to 50 specific points. PRINCIPLES OF OPERATION PRINCIPLES OF OPERATION The logging system comprises a subsurface instrument equipped to initiate and detect radiation from carbon, and surface gear to analyze and record the amount of such radiation in a format that facilitates formation evaluation. To initiate the emission of radiation, a source of 14-MeV neutrons is required. To detect the radiation, a scintillation spectrometer is used. And to assay the abundance of formation carbon by analyzing the detected radiation, a multichannel pulse-height analyzer system is employed. SPEJ P. 463

Automated analysis of deoxyribonucleic acid, protein and nuclear to cytoplasmic relationships in tumor cells and gynecologic specimens.

Quantitative two-color fluorescence staining techniques, coupled with flow system multiparameter cell analysis and sorting instrumentation, have been used for rapid, simultaneous determination of deoxyribonucleic acid, protein, nuclear (N) and cytoplasmic (C) diameters and N:C ratios in mammalian tumor cells and human gynecologic specimens. Cells stained in suspension for deoxyribonucleic acid and total protein content, respectively, with propidium iodide (red fluorescence) and fluorescein isothiocyanate (green fluorescence), enter a flow chamber and intersect an argon laser beam which excites cellular fluorescence. Optical sensors measure both red and green fluorescence plus the time duration of each fluorescence signal which is proportional to nuclear and cytoplasmic diameters, respectively. The resulting signals are processed and displayed as frequency distribution histograms using a multichannel pulse height analyzer. Cells are also sorted based on N:C ratios. Illustrative examples of preliminary two-color fluorescence analysis and sorting of mouse squamous tumor cells and human exfoliative vaginal cells are presented.

Multiparameter analysis and sorting of mammalian cells

An improved multisensor cell sorting instrument for quantitative analysis and sorting of cells has been developed. Cells stained with fluorescent dyes enter a flow chamber where cell volume, fluorescence, and light scatter sensors simultaneously measure multiple cellular properties. Cells then emerge in a liquid jet that is broken into uniform liquid droplets. Sensor signals are electronically processed in one of several ways for optimum cell discrimination and are displayed as pulse-amplitude distributions using a multichannel pulse-height analyzer. Processed signals activate cell sorting according to preselected parametric criteria by electrically charging droplets containing cells and electrostatically deflecting them into collection vessels. Illustrative examples of multiparameter cell analysis and sorting experiments using a model mouse tumor cell system, human and animal leukocytes, and cultured mammalian cells are presented.

発光分光分析による鋼中アルミニウムの形態別分析法の研究

In previous papers described for analysis of Al in steel by emission spectroscopy, the analytical values were affected mainly by the amounts of Al2O3 in the sample, the difference in a situation of the grinding of the sample surface and so on.For the elimination of these affections, a study has been carried out on the behaviors of integrated photo-current pulses occured from every unit discharge.As the result of many considerations, it was found that Al in steel has been able to be determined metallographically; Al as in the homogeneous state (acid-soluble Al at chemical analysis) and as in the inhomogeneous one (insoluble Al) respectively. The efficient and appropriate informations used to the metallographic analysis was derived from the distribution of integrated photo-current pulses.This distribution was obtained by the following techniques. The pulses occured from every unit discharge were shaped and amplified suitably and must be put through multi-channel pulse height analyzer circuit. After treatment in P. H. A., the output pulse amplitude shows the distribution due to the metallographical state of Al in the sample.The median value shows T. Al, and the shift of the median values during spark time show insol. Al in the sample, respectively.In this method, the results obtained are 0.0015% Al (δ)(at the range of 0-0.05% Al) for T. Al and 0.0018% Al (δ)(at 0-0.04% Al) for sol. Al respectively.

Electrical sizing and counting of platelets in whole blood.

Hydrodynamic focusing with a jet close to the orifice of a Coulter counter is used as a detector for particle sizing, with a substantial increase in resolution and size range. To maintain these improvements during analogue-digital conversion, zero crossover triggering for sample and hold and a pulse-shape dependent inhibition before address transfer to the memory of a multichannel pulse-height analyser have been performed. Results are given showing size distributions of polystyrene latex particles, fixed red cells and living red cells with platelets from whole blood.

Reduction of the counting losses in a time analyser by the use of an intermediate memory

In the analysis of time-of-flight experiments the counting losses due to the various counting components may cause serious disturbance to the spectral data obtained. The dead time of the time analyser contributes most to the counting losses. A theoretical formula was introduced to estimate the correction for counting losses in the case of constant counting rates in all the analyser channels. Experimental checking of the spectrum distortion at constant pulse rates at the analyser input has been investigated. The time analyser used in this experiment is composed mainly of a time-to-pulse height converter and a multi-channel pulse height analyser. To reduce counting losses, we have used an additional pulse height analyser in parallel with the main analyser to act as an intermediate memory. It was found that this method helps to reduce appreciably the counting losses of the time analyser.

Neutron spectra estimation from proton recoil data

A method to unfold neutron spectra from experimental proton recoil data in the form of a Multi-Channel Pulse Height Analyzer Histogram is developed and tested. Since the energy spectrum of a neutron source is essentially the probability density function of the energy with which neutrons are emitted, the theory of random variables is used to develop the basic unfolding method. Time series analysis and Fourier analysis is subsequently applied to obtain smooth estimates of the neutron spectra. The method is tested by its application to experimental data produced with an NE-213 fast neutron spectrometer system and a Benjamin-type spectrometer system. Spectra of neutron sources such as Pu-Be and Cf-252 are unfolded. The spectral estimates are compared with calculations, published data and results obtained with other unfolding methods.

Chemical State Analysis of Sulfur in Coal by High Resolution Fluorescent x-Ray Spectrometry

Chemical states, especially oxidation states, are knowm to have various effects on x-ray spectra from sulfur. The efiects, however, are not large and it is rather difficult to observe them with a conventional commercially available x-ray spectrometer. A high resolution two-crystal x-ray spectrometer recently constructed was used for the observation of these phenomena in order to utilize them for the chemical state analysis of sulfur in coal.Pressed samples were excited with x-rays from a Cr target tube. Resultant fluorescent x-rays (SKα) were analyzed with the two-crystal spectrometer (prototype of Toshiba AFV 701) equipped with Ge (111) or ADP (101) crystals. A gas flow proportional counter was used as a detector. Pulses from the detector were stored in a multichannel pulse height analyzer (multiscaler mode. In case of a low intensity, the spectrometer was scanned repeatedly and pulses were accumulated several times.The energy of SKα increases with the increase of oxidation number. The spectrum from Na2S2O3, which contains S2- and S6+, shows two components which correspond to S2- in FeS and S6+ in Na2SO4. This fact means that qualitative and quantitative chemical state analyses can be performed by measuring SKα spectra precisely.SKα from coal has a strong peak and a weak shoulder which is on the short wavelength side of the intense main peak. These two components were concluded to be due to S2- and S6+ by comparing their positions with the spectra of known compounds.Ouantitatne analyses of S2- and S6+. were performed with a non-linear least square method. The result for variaus coals were discussed (total S: 0.6-3. 3%, S6+: 5-28).

Beta spectrum analysis: a new method to analyze mixtures of beta-emitting radionuclides by liquid scintillation techniques

A description is given of a method to couple a liquid scintillation spectrometer to a multichannel pulse-height analyzer to record beta spectra simultaneously with three different energy ranges. Spectra of tritium, carbon-14 and phosphorus-32 recorded by this method are presented. Analyses of the beta spectra are performed by a least-squares technique, and the results are shown in tabular form.