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Simple multifunction discriminator for multichannel triggers

Description: A simple version of a multifunction timing discriminator using only two integrated circuits is presented. It can be configured as a leading edge, a constant fraction, a zero cross or a dual threshold timing discriminator. Since so few parts are used, it is well suited for building multichannel timing discriminators. Two versions of this circuit are described: a quadruple multifunction discriminator and an octal constant fraction trigger. The different compromises made in these units are discussed. Results for walk and jitter obtained with these are presented and possible improvements are disussed.
Date: October 1, 1982
Creator: Maier, M.R.
Partner: UNT Libraries Government Documents Department

TIME-WALK CHARACTERISTICS OF AN IMPROVED CONSTANT FRACTION DISCRIMINATOR

Description: A modification to a constant fraction discriminator design published earlier makes the observed time walk less than 30 ps over an input voltage range of 0.15 to 2.5 V. This performance makes time-walk corrections unnecessary in many situations.
Date: September 1, 1980
Creator: Wozniak, G. J.; Richardson, L. W. & Maier, M. R.
Partner: UNT Libraries Government Documents Department

Adaptive Readout Technique For A Sixteen Channel Peak Sensing ADC In the FERA Format

Description: An adaptive, variable block-size readout technique for use with multiple, sixteen-channel CAMAC ADCs with a FERA-bus readout has been developed and designed. It can be used to read data from experiments with or without coincidence, i.e. singles, without having to change the readout protocol. Details of the implementation are discussed and initial results are presented. Further applications of the adaptive readout are also discussed.
Date: November 1, 1998
Creator: Yaver, H.; Maier, M.R.; Lindstrom, D. & Ludewigt, B.A.
Partner: UNT Libraries Government Documents Department

Multichannel analog to digital converter and readout system for the time projection chamber

Description: The Time Projection Chamber (TPC) project involves the characterization of signals arriving at approximately 20,000 separate detector wires and pad electrodes. The characterizaton requires measurement of the signal amplitudes in 100 ns time slices over a total time of 20 ..mu..s (the total chamber drift time). Charge Coupled Devices (CCD's) are used to store an image of the 20 ..mu..s span of signals and the image is played back at a low rate (50 ..mu..s time slices, i.e., a time expansion of 500:1). Digitization of the 20,000 parallel signals at the output of the CCD's must therefore be accomplished in 50 ..mu..s and readout of digital data into the computer system must also be accomplished in this time. Many zeros occur in the data, a fact which reduces the data handling demands on the readout system, but does not reduce the stringent requirements on the digitizer. Therefore, the requirements on the digitizer are highlighted by the need to perform 9-bit digitizing in less than 50 ..mu..s. Furthermoree, a double buffering scheme must be used to permit interleaving digitizing and digital readout cycles. A description is given of the implementation of this concept and some possible applications for other experiments which require many Analog to Digital Converter (ADC) channels.
Date: October 1, 1978
Creator: Maier, M.R.; Olson, S.R.; Nakamura, M. & Goulding, F.S.
Partner: UNT Libraries Government Documents Department

Quad delay gate generator (LBL No. 21X6691 P-2)

Description: A quad delay gate generator has been designed and packaged in a single-width NIM module. Both delay times and gate widths may be set continuously from 25 ns to 120 ..mu..sec. In normal operation, the gate follows the delay time unless a ''stop'' pulse cuts it short. Alternatively, the module may be operated in a bipolar mode, where the delay time is set by the input ''start'' pulse and reset by the input ''stop'' pulse. Modes and coarse time ranges are set via an octal DIP switch on the front panel. Fine adjustments of the delay and gate width are made via two twenty-turn potentiometers. Stability over a several day period was measured at approx. 250 ps on the 120 ns full scale range. LEDs gives a visual indication of both the input rate and the dead time.
Date: August 1, 1986
Creator: McDonald, R.J.; Maier, M.R.; Landis, D.A. & Wozniak, G.J.
Partner: UNT Libraries Government Documents Department

The SISWICH, a detector telescope with intrinsic calibration

Description: Phoswich counters have gained widespread popularity as detectors for medium energy charged particles. They provide adequate energy resolution and particle identification up to atomic numbers Z = 20. However, the question of calibration has not been resolved satisfactorily. To overcome this difficulty we have built a Silicon-Scintillator SandWICH (SISWICH). This detector consists of a silicon PIN photo diode glued to the front of a CsI (T{ell}) scintillator crystal. The signal coming from the PIN diode contains the energy loss of the particle in the silicon, which is fast (nuclear counter effect), and the light output of the scintillator which is slow. The component coming from the nuclear counter effect can be calibrated with a pulser. Therefore, since the energy loss of a particle with known Z has been measured, its energy is known, and this can be used to calibrate the signal from the scintillator. Results will be shown.
Date: October 1, 1992
Creator: Friese, J.; Gillitzer, A.; Koerener, H. J.; Reinhold, J.; Peter, M. & Maier, M. R.
Partner: UNT Libraries Government Documents Department

Charged particle identification with modules of the plastic ball

Description: The low energy pion channel (LEP) at LAMPF was used to calibrate the response of modules of the Plastic Ball detector for positive pions and protons. The detection efficiency was measured at various energies. The resolution and efficiency were found to be independent of the point at which the particle entered the detector. Scattered out particles could be well detected by including neighbouring detectors in the analysis.
Date: October 1, 1980
Creator: Gutbrod, H.H.; Maier, M.R.; Ritter, H.G.; Warwick, A.I.; Weik, F.; Wieman, H. et al.
Partner: UNT Libraries Government Documents Department

A high resolution 14-bit ADC for Gammasphere Project

Description: A system of 110 high performance A/D converters, required for the Gammasphere Project at the Lawrence Berkeley Laboratory, is described. The ADCs are compact, linear ([plus minus])0.006% integral, [plus minus]0.5% differential, with a conversion deadtime of 5.3 [mu]s and channel profile flatness of 50% over a 13-bit range. The converter is based on a new low power (0.25 W), low cost, monolithic high speed sampling ADC, exibiting a very high stability and no missing codes over the entire 16-bit range. Differential linearity was achieved by applying the Gatti method'', covering a 8-bit range. Measured data and methods of testing the ADC are also resented.
Date: October 1, 1992
Creator: Turko, B.T.; Arthur, A.A.; Galvin, J.E.; Maier, M.R. & Zizka, G.J.
Partner: UNT Libraries Government Documents Department

The sixteen channel CAMAC constant fraction discriminator for APEX

Description: We report on the construction and the performance of a sixteen channel constant fraction discriminator (CFD) for the Atlas Positron Experiment (APEX). We have used an integrated circuit (IC), recently introduced commercially, which contains all the electronic building blocks needed to construct a CFD. We have placed 16 channels of CFD into a CAMAC module. An important feature is the time to charge converter (TQC) that we have included for every CFD channel. Its calibration constant is controlled via CAMAC. The TQC allows the use charge sensitive analog to digital converters (QDC) for timing measurements. Results for CFD walk, resolution and crosstalk as well as for TQC linearity will be presented.
Date: November 1, 1991
Creator: Maier, M. R.; Robertson, M.; Wolfs, F. L. H. & Perera, P. A. A.
Partner: UNT Libraries Government Documents Department

A high resolution 14-bit ADC for Gammasphere Project

Description: A system of 110 high performance A/D converters, required for the Gammasphere Project at the Lawrence Berkeley Laboratory, is described. The ADCs are compact, linear ({plus_minus})0.006% integral, {plus_minus}0.5% differential, with a conversion deadtime of 5.3 {mu}s and channel profile flatness of 50% over a 13-bit range. The converter is based on a new low power (0.25 W), low cost, monolithic high speed sampling ADC, exibiting a very high stability and no missing codes over the entire 16-bit range. Differential linearity was achieved by applying the ``Gatti method``, covering a 8-bit range. Measured data and methods of testing the ADC are also resented.
Date: October 1, 1992
Creator: Turko, B. T.; Arthur, A. A.; Galvin, J. E.; Maier, M. R. & Zizka, G. J.
Partner: UNT Libraries Government Documents Department

A sixteen channel peak sensing ADC for singles spectra in the FERA format

Description: To read out multi-element small X-ray detectors for X-ray fluorescence application with synchrotron radiation one needs the capability to record multiple singles spectra for each detector element at high rates. We have developed a sixteen channel 11 bit peak sensing ADC in a CAMAC module. We use the FERA readout bus to place the data into a commercially available histogramming module developed to generate multiple histograms from FERA ADCs. The sixteen channels digitize shaped pulses from the detectors without external gating. The digitizing time is 8 {mu}sec, the peak acquisition time is {>=} 2 {mu}sec. The module contains a LiFO to permit block transfers in order to minimize dead times associated with the readout. There is a common CAMAC controlled analog threshold for noise suppression and a 16 bit mask to enable or disable individual ADCs. Differential non-linearity is less than +8% / -4%. A {gamma}-ray spectrum collected using this ADC is presented.
Date: October 1, 1995
Creator: Maier, M.R.; Ludewigt, B.A.; Rossington, C.S.; Yaver, H. & Zaninovich, J.J.
Partner: UNT Libraries Government Documents Department

Low cost pulse shaper for use with Silicon PIN diodes

Description: We have developed a flexible, small and low cost analog pulse shaper and amplifier circuit for Silicon PIN photodiode detectors. The shaping amplifier produces both a ``fast`` negative output signal with less than 10 ns rise time for timing measurements and a ``slow`` positive output signal with peaking times from 500 ns to 10 {mu}s for energy measurements. The gain for the two signals can be set independently. The maximum output amplitude for the fast signal is {minus}1.5V and +10V for the slow signal. The resolutions for the energy channel was <10 keV electronic contribution giving a total of 17 keV with {alpha} particles. The resolution for the timing channel was < 1ns electronics with a total of 2 ns with {alpha} particles. The price is $200 per channel. The whole circuit fits on a board of 7.5 cm {times} 3.5 cm.
Date: October 1, 1992
Creator: Ciric, M.; Friese, J.; Koerner, H. J. & Maier, M. R.
Partner: UNT Libraries Government Documents Department

Low cost pulse shaper for use with Silicon PIN diodes

Description: We have developed a flexible, small and low cost analog pulse shaper and amplifier circuit for Silicon PIN photodiode detectors. The shaping amplifier produces both a fast'' negative output signal with less than 10 ns rise time for timing measurements and a slow'' positive output signal with peaking times from 500 ns to 10 [mu]s for energy measurements. The gain for the two signals can be set independently. The maximum output amplitude for the fast signal is [minus]1.5V and +10V for the slow signal. The resolutions for the energy channel was <10 keV electronic contribution giving a total of 17 keV with [alpha] particles. The resolution for the timing channel was < 1ns electronics with a total of 2 ns with [alpha] particles. The price is $200 per channel. The whole circuit fits on a board of 7.5 cm [times] 3.5 cm.
Date: October 1, 1992
Creator: Ciric, M.; Friese, J.; Koerner, H.J. (Technische Univ. Muenchen (Germany)) & Maier, M.R. (Lawrence Berkeley Lab., CA (United States))
Partner: UNT Libraries Government Documents Department

The sixteen channel CAMAC constant fraction discriminator for APEX

Description: We report on the construction and the performance of a sixteen channel constant fraction discriminator (CFD) for the Atlas Positron Experiment (APEX). We have used an integrated circuit (IC), recently introduced commercially, which contains all the electronic building blocks needed to construct a CFD. We have placed 16 channels of CFD into a CAMAC module. An important feature is the time to charge converter (TQC) that we have included for every CFD channel. Its calibration constant is controlled via CAMAC. The TQC allows the use charge sensitive analog to digital converters (QDC) for timing measurements. Results for CFD walk, resolution and crosstalk as well as for TQC linearity will be presented.
Date: November 1, 1991
Creator: Maier, M.R. (Lawrence Berkeley Lab., CA (United States)); Robertson, M. (National Superconducting Cyclotron Lab., East Lansing, MI (United States)); Wolfs, F.L.H. & Perera, P.A.A. (Rochester Univ., NY (United States). Nuclear Structure Research Lab.)
Partner: UNT Libraries Government Documents Department

The ATLAS Positron Experiment -- APEX

Description: APEX -- the ATLAS Positron Experiment -- is designed to measure electrons and positrons emitted in heavy-ion collisions. Its scientific goal is to gain insight into the puzzling positron-line phenomena observed at the GSI Darmstadt. It is in operation at the ATLAS accelerator at Argonne National Lab. The assembly of the apparatus is finished and beginning 1993 the first positrons produced in heavy-ion collisions were observed. The first full scale experiment was carried out in December 1993, and the data are currently being analyzed. In this paper, the principles of operation are explained and a status report on the experiment is given.
Date: March 1, 1994
Creator: Ahmad, I.; Back, B. B.; Betts, R. R.; Dunford, R.; Kutschera, W.; Rhein, M. D. et al.
Partner: UNT Libraries Government Documents Department