Multi-channel analyzer

Fig. 3.3 Velocity control and synchronization of data recording by the multi-channel analyzer (MCA) operated in MCS mode with 512 channels. For the common triangular velocity profile shown here the spectrum is recorded twice, because each velocity increment is reached upon sweeping up and down. The sense of the velocity scales may also be opposite to that shown here, which means the MCA sweep may also start at...

Fig. 3.7 Pulse-height analysis (PHA) Function of the single-channel analyzer (SCA) and data recording by the multi-channel analyzer (MCA). The output (L) of the SCA yields a 5 V squareshaped pulse, a so-called TTL pulse for each y-pulse matching the voltage selection window. The SCA is set to select the Mossbauer pulses for the subsequent measurement...

Fig. 3.1. Schematic diagram of a TCSPC setup. Using a fast timing device (e.g., time-to-amplitude-converter) the time is measured between the excitation pulse and the detection of a photon. By repeating this procedure many times a decay curve is measured. TAC time to amplitude convertor, MCA multi channel analyzer, PC personal computer. 

The hematite with adsorbed Co-57 or Sb-119 along with the solution was subjected to emission Mossbauer measurement at 24 1°C with the experimental setup shown in Figure 2. The absorber, Fe-57-enriched potassium ferrocyanide (0.5 mg Fe-57/cm2) or barium stannate (0.9 mg Sn-119/cm2), was driven by a Hanger 700-series Mossbauer spectrometer connected to a Tracor-Northern TN-7200 multi-channel analyzer. The Mosssbauer gamma-rays of Co-57 and Sb-119 were detected respectively with a Kr(+3% carbon dioxide)-filled proportional counter and with a 2 mm-thick Nal(Tl) scintillation counter through 65 pm-thick Pd critical absorber for Sn K X-rays. The integral errors in the relative velocity were estimated to be of the order of 0.05 mm/s by repeated calibration measurements using standard absorbers. 

Figure 12. Low level counting equipment consisting of two RIDL multi-channel analyzers with accessories and a modified gun barrel shield...

We have used a Reticon photodiode array and an Optical Multi-channel Analyzer to measure optical density changes Induced in photovisual materials using this technique. The Reticon is a device which incorporates a linear high density monolithic array of silicon photodiodes with integrated scanning circuits for serial readout. The array consists of 128... 

As discussed above, a convenient way of measuring the detonation velocity is to convert the light signal using a fast photodiode that has a rising time of about 10 ns into an electric signal that may be recorded by either a fast oscilloscope (Fig. 7.13) or a multi-channel analyzer (Fig. 7.14). 

Analysis. The analytical system used for gamma-ray measurements consisted of a lithium drifted germanium (GeLi) crystal detector, a 4096 multi-channel analyzer, a PDP 11 computer, and a cassette magnetic tape storage. The germanium detector crystal has a volume of 55 cm with FWHM resolution of 2.3 keV at 1.33 MeV. The computer was used to analyze the gamma ray spectra, to identify the radio isotopes, and to calculate the concentration (Table III). 

Multi-channel analyzer -(+ amplifiers, power units, etc.)... 

Figure 6, Multi-channel analyzer display for glycerin particle calibration...

Malvern ALPS 100 system liquid particle counter is a modular system that can be used with an autosampler for multiple samples or with an online sampler for direct measurement of flowing liquids. It can be used with sample volumes down to 0.5 ml and uses a built-in multi-channel analyzer to perform size distribution analyses of low concentration dispersions. Suitable for both aqueous liquids and solvents, it measures up to 50 size bands in the 2 to 100 pm or 3 to 150 pm size range with output from a built-in thermal printer or external dot matrix printer. 

Raman spectra were obtained with a Dilor-Jobin Yvon-SPEX spectrometer equipped with an optical multi-channel analyzer. The Raman spectra were excited with the 488-nm line of an Ar-ion laser. 

The electronic components needed for processing the detector signals have evolved into standardized modular units, and are relatively simple to select. One important factor when using multi-channel analyzers is the analyzer dead-time. Typically, a multi-channel analyzer receives a pulse, digitizes that pulse, and stores... 

For reference, a spectrophotometer/colorimeter with direct concentration readout costs on the order of 2000 a digital Na/K flame photometer with an automatic sample-diluter, about 4000 a flexible, computer-controlled, single-channel analyzer under 25,000 a computer-based parallel-fast analyzer, about 50,000 and a multi-channel analyzer from about 80,000 to well over 200,000. 

Multi-channel Analyzers. The first widely adopted multi-channel system was the SMA 12/60 (jequential /Multiple analyzer) introduced by Technicon in 1967. Built on the continuous-flow principle, it is similar in operation to the single-channel analyzer shown in Figure 24.12, but with the sample split into 12 channels. This generates 12 results sequentially on each sample at the rate of 60 samples, calibrators, and controls per hour. The 12/60 helped to establish the role of the screening battery or profile in diagnostic medicine. 

Other multi-channel analyzers on the market are discrete sampling systems that feature test selection for each sample. The earlier generation Hycel Mark X and Mark 17 does this with a push-button panel, whereas a dedicated computer does it on the Ortho AcuChem Microanalyzer ( Basic ) and the Coulter Chemistry System. All of these systems offer various combinations and degrees of the features... 

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