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Upgrade of NSLS timing system

Description: We report on the progress of the new NSLS timing system. There are three types of requirements for NSLS timing system: clocks, synchronization and trigger circuits. All ring revolution frequency clocks are generated using ECL and high speed TTL logic. The synchronization circuits allows to fill both storage rings with any bunch pattern. The triggers are generated by using commercially available digital delay generators. The delay unit`s outputs are ultrastable, with a resolution of 5 ps, and are programmed by computer via IEEE 488 interface. The block diagrams, description of all major timing components and the present status are provided in this paper.
Date: May 1, 1995
Creator: Singh, O.; Ramamoorthy, S.; Sheehan, J. & Smith, J.
Partner: UNT Libraries Government Documents Department

Application of PC's and Linux to the CDF Run II level-3 trigger

Description: For Run II, the CDF Level-3 trigger must provide a sustained input bandwidth of at least 45 MBytes/set and will require processing power of at least 45000 MIPS to perform the necessary reconstruction and filtering of events. We present a distributed, scalable architecture using commod- ity hardware running the Linux operating system. I/O and CPU intensive functions are separated into two types of nodes; �converter� nodes receive event fragments via ATM from Level 2 computers and distribute complete events to �processor� nodes via multiple fast ethernets. We present re- sults from a small-scale prototype roughly equivalent to a 1/16th vertical slice of the final system. With this hardware we have demonstrated the capability of sustained I/O rates of 15 MBytes/set, more then three times the required baseline performance. We discuss PC hardware and Linux software issues and modifications for real time performance.
Date: December 1998
Creator: Fromm, Jim; Holmgren, Don; Kennedy, Robert; Patrick, Jim; Petravick, Don; Rechenmacher, Ron et al.
Partner: UNT Libraries Government Documents Department

Weighting mean timers for high energy physics electronics

Description: A new family of electronics circuits, weighting mean timer, is presented in this technical memo. Weighting mean timers can be used in high energy physics experiment electronics to implement the \concurrence" condition in hardware trigger stage. Several possible architectures of weighting mean timers have been discussed.
Date: November 1, 1998
Creator: Wu, J.
Partner: UNT Libraries Government Documents Department

Implementation of the shower max electron trigger at CDF

Description: The authors have built and installed new electronics which brings the central shower max detector into the CDF Level-2 trigger. By matching a stiff track from the central fast track processor to an associated shower max cluster, this trigger improvement reduces the electron Level-2 cross section by approximately 50% while retaining greater than 85% of real electrons and allows the authors to lower their electron trigger threshold.
Date: June 1, 1994
Creator: Byrum, K.; Dawson, J.; Nodulman, L.; Wicklund, A.B.; Amidei, D.; Burkett, K. et al.
Partner: UNT Libraries Government Documents Department

Possible satellite-based observations of the 1997 Leonid meteoroids

Description: The Block IIA GPS satellites are equipped with a sensor designed to detect electromagnetic transients. Several phenomena will produce triggers in this sensor. They include earth-based electromagnetic transients such as lightning and two space-based phenomena--deep dielectric discharge and meteoroid or hyper-velocity micro-gram particle impact (HMPI). Energetic electrons in the GPS environment cause the deep dielectric charging. HMPIs cause triggers through the transient electric fields generated by the ejecta plasma. During the 1997 Leonid passage the energetic particle fluxes were very low. In the presence of such low fluxes the typical median trigger rate is 20 per minute with a standard deviation of about 20 per minute. Between 0800 UT and 1200 UT on November 17, 1997, the sensor on a specially configured satellite observed trigger rates more than 10 sigma above the nominal median rate. Sensors on other Block IIA GPS satellites also observed excess triggers during November. Detection is enhanced when the sensor antenna is oriented into the Leonid radiant. While many questions persist the authors feel that it is likely that the excess events during the November interval were caused by the close approach of the satellites to the Leonid meteoroid path.
Date: December 1, 1998
Creator: Pongratz, M.B.; Carlos, R.C. & Cayton, T.
Partner: UNT Libraries Government Documents Department

D0 luminosity monitor constant for the 1994-1996 Tevatron run

Description: The D0 experiment calculates its luminosity using the visible cross section (luminosity monitor constant) {sigma}{sub L0} for its Level 0 trigger based on the world average {anti p}p inelastic cross sections at {radical}s - 1.8 TeV. For the 1992-1993 Tevatron Run (1A), the luminosity monitor constant was determined to be {sigma}{sub L0} = 46. 7{+-}2.5 mb. For the 1994-1996 Tevatron Run (1B/1C), the luminosity monitor constant changed slightly with an upgrade to the electronics in the Level 0 trigger. The luminosity monitor constant becomes on average {sigma}{sub L0} - 44.53 {+-} 2.37 mb for Run 1B/1C. In addition, small corrections for halo and multiple single diffraction are included in integrated luminosity determinations.
Date: June 1, 1997
Creator: Bantly, J., Krane, J., Owen, D., Partridge, R., Paterno, L.
Partner: UNT Libraries Government Documents Department

Continued study of the time stability of a small water Cerenkov detector

Description: This note describes continued studies at Fermilab of the long term stability of a small water Cerenkov tank. Previous results are presented for studies between November, 1997 and October, 1998. The data given here continue these measurements through December, 1998, when the tank and electronics were moved to a different location, and then to November, 1999. The water tank, bag liner, water, photomultiplier tube, and data acquisition software were unchanged for the additional measurements from June to November, 1999. However, some details of the geometry of the trigger counters relative to the tank and of the electronics may have differed. The setup for the 1999 results is described in this note. The same analog-to-digital converter (ADC) was used for both time periods. Its pedestal was quite stable during the 1997--1998 measurements, but sizeable changes were observed in the more recent runs. As a result, dedicated pedestal runs were performed, and a number of additional tests were conducted.
Date: April 3, 2000
Creator: Strom, D.; Glass, H.; Spinka, H. & Thomure, M.
Partner: UNT Libraries Government Documents Department

Trigger circuits for the PHENIX electromagnetic calorimeter

Description: Monolithic and discrete circuits have been developed to provide trigger signals for the PHENIX electromagnetic calorimeter detector. These trigger circuits are deadtimeless and create overlapping 4 by 4 energy sums, a cosmic muon trigger, and a 144 channel energy sum. The front end electronics of the PHENIX system sample the energy and timing channels at each bunch crossing (BC) but it is not known immediately if this data is of interest. The information from the trigger circuits is used to determine if the data collected is of interest and should be digitized and stored or discarded. This paper presents details of the design, issues affecting circuit performance, characterization of prototypes fabricated in 1.2 {micro}m Orbit CMOS, and integration of the circuits into the EMCal electronics system.
Date: November 1, 1997
Creator: Frank, S.S.; Britton, C.L. Jr.; Winterberg, A.L. & Young, G.R.
Partner: UNT Libraries Government Documents Department

Early-time turn-on characteristics of a high current thyristor

Description: Studies and experiments aimed at increasing the turn-on speed of high current thyristors have been carried out in recent years to meet an expanding need in the pulsed power handling capacity and high pulse repetition rate capability. The present tests were conducted to measure the early-time turn-on characteristics of ABB 2003-45A02 thyristors and to determine whether special triggering techniques could raise the safe turn-on rate to the 100,000 A/{micro}s range which would qualify it for applications such as direct drive accelerator circuits. Results were encouraging. With these devices and special triggering techniques a maximum turn-on rate of 65,373 A/{micro}s and a peak current of 19,040 A were recorded at a pulse repetition rate of 5 Hz.
Date: July 1, 1996
Creator: Roose, L.D. & Rohwein, G.J.
Partner: UNT Libraries Government Documents Department

Positron Accumulator Ring (PAR) power supply

Description: The Positron Accumulator Ring (PAR) consists of 8 dipole magnets connected in series. These magnets are energized via one 12-pulse dc power supply. The power supply consists of four phase controlled half-wave wye group converters. Each of the two half-wave converters are connected through an interphase transformer to obtain a full-wave converter with 120{degrees} conduction. The input voltage for these two half-wave converters are 180{degrees} apart. The two full-wave converters are connected in parallel through a third interphase transformer. This type of connection of the converters not only provides the required output current, it also improves the input power factor of the power supply. The output of the wye group converters is filtered through a passive L-R-C filter to reduce the ripple content of the output current. At low current values of the power supply the current ripple is high, thus a large filter is needed, which adds to the cost of the power supply, however at high output current levels, the current ripple is less severe. The large size of the filter can be reduced by adding an anti-parallel rectifier diode(D1) to the output of the power supply. A freewheeling diode(D2) is connected before the choke to circulate the current once the power supply is turned off. In order to measure the current in the magnet a high precision, low drift, zero flux current transductor is used. This transductor senses the magnet current which provides a feedback signal to control the gating of the converter`s thyristors. A true 14 bit Digital to Analog Converter (DAC) is programmed by the control computer for the required current value, providing a reference for the current regulator. Fast correction of the line transients is provided by a relatively fast voltage loop controlled by a high gain slow response current loop.
Date: August 1, 1995
Creator: Fathizadeh, M.
Partner: UNT Libraries Government Documents Department

Optically induced surface flashover switching for the dielectric wall accelerator

Description: Fast, low jitter command triggered switching is key to the successful implementation of the dielectric wall accelerator (DWA). We are studying a UV induced vacuum surface flashover switch for this purpose. We present our initial data using a Nd:YAG laser incident onto a high gradient insulator surface at 1{omega}, 2{omega}, and 4{omega}. Best 1{sigma} jitter was <1 ns with no degradation of the switch after 500 shots.
Date: April 27, 1995
Creator: Sampayan, S.; Caporaso, G.; Carder, B.; Norton, M.; Trimble, D. & Elizondo, J.
Partner: UNT Libraries Government Documents Department

A possible level 0 trigger scheme for the STAR EMC

Description: We propose a level 0 trigger for the STAR Electromagnetic Calorimeter, EMC, which provides a global energy sum and sums over cells appropriate for triggering on direct gammas and jets. It is implemented in analog at low level and digitally with FPGA`s at higher level. It will provide trigger information in less than 800 nanoseconds.
Date: May 1, 1994
Creator: Underwood, D.
Partner: UNT Libraries Government Documents Department

The level 1 central tracking trigger for the D-Zero upgrade

Description: The D0 level 1 tracking trigger uses data from the scintillating fiber tracker, the central and forward preshower detectors, the muon system and the calorimeter. Tracks are found in the scintillating fiber tracker with transverse momentum greater than 1.5 GeV/c. The tracks are then sent to the central preshower detector for electron tagging and to the muon system for muon tagging. Preshower clusters are also used for identifying photon candidates. These multi detector triggers are then sent to the level 1 Trigger Framework where they are further combined with the calorimeter to create the final level 1 trigger. This paper presents an overview of the level 1 trigger system with emphasis on the use of large programmable logic devices (PLD�s) in an extensible system architecture that allows complex, multi detector triggers.
Date: July 22, 1999
Creator: F. Borcherding, S. Grunendahl, M. Johnson, K. Yip
Partner: UNT Libraries Government Documents Department

SUMAC: A monitor and control tree for multi-FPGA systems

Description: The BTeV pixel trigger is a data acquisition system capable of finding tracks and vertices in real time in the BTeV pixel detector array. The trigger uses some 3000 processing elements (DSPs) arranged in three processing levels to handle a raw data rate of nearly 100 Gigabytes per second and bring the trigger rate down to 10 KHz. The trigger system has more than 6000 programmable elements, including Field Programmable Logic Arrays (FPGAs), microprocessors (DSPs, interface to the monitor and control tree through FPGAs), and others. Sumac (Serial Utility Monitor and Control tree) is used for configuring and monitoring of these devices. Its primary function is the downloading of FPGA bit streams, microprocessor programs, chip configurations, and test data. In addition, remote cpus and other devices can send messages and status back to the host. The Sumac system is capable of handling several thousand remote devices from a single host PC. Because it stores configuration data in local flash eeproms, it will be capable of achieving a complete system reboot in less than 1 second. The Sumac system is a tree hierarchy connected via high-speed serial links. Typically each board in the system will have a control node which accepts a single upstream serial link and fans out to as many as 32 downstream links. The downstream links can connect to FPGAs or to other control nodes for further fanout.
Date: July 27, 1999
Creator: Gao, Mingshen
Partner: UNT Libraries Government Documents Department

Design of a secondary-vertex trigger system

Description: For the selection of beauty and charm events with high efficiency at the Tevatron, a secondary-vertex trigger system is under design. It would operate on forward-geometry events. The system would use on-line tracking of all tracks in the vertex detector, to identify events with clearly detached secondary vertices.
Date: June 1, 1995
Creator: Husby, D.; Chew, P.; Sterner, K. & Selove, W.
Partner: UNT Libraries Government Documents Department

Power supplies for the injector synchrotron quadrupoles and sextupoles

Description: This light source note will describe the power supplies for the injector synchrotron quadrupole and sextupole magnets. The injector synchrotron has two families of quadrupole magnets. Each family consists of 40 quadrupole magnets connected in series. These magnets are energized by two phase-controlled, 12-pulse power supplies. Therefore, each power supply will be rated to deliver the necessary power to only 40 quadrupole magnets. The two families of sextupole magnets in the injector synchrotron each consists of 32 sextupole magnets connected in series, powered by a phase-controlled power supply. Thus, each power supply shall be capable of delivering power to only 32 sextupole magnets.
Date: July 1, 1995
Creator: Fathizadeh, M.
Partner: UNT Libraries Government Documents Department

The BTeV Trigger System

Description: BTeV is a dedicated beauty and charm experiment proposed for the Fer- milab Tevatron. The broad physics program envisaged for BTeV requires a trigger that is efficient for a wide variety of heavy-quark decays, includ- ing those to all-hadronic final states. To achieve this, we plan to trigger on evidence of detached vertices at the very first trigger level, taking ad- vantage of fast-readout pixel detectors to facilitate fast pattern recognition. Simulations show that 100-to-1 rejection of light-quark background events can be achieved at Level 1 using specialized trackfinding hardware, and that an additional factor of 10 to 100 in data reduction can be achieved using general-purpose-processor farms at Levels 2 and 3. This is adequate to allow data-taking at luminosities in excess of 2 x 10<sup>32</sup> cm<sup>-2</sup>s<sup>-1</sup>.
Date: October 8, 1999
Creator: Kaplan, Daniel M.
Partner: UNT Libraries Government Documents Department

Two-klystron Binary Pulse Compression at SLAC

Description: The Binary Pulse Compression system installed at SLAC was tested using two klystrons, one with 10 MW and the other with 34 MW output. By compressing 560 ns klystron pulses into 70 ns, the measured BPC output was 175 MW, limited by the available power from the two klystrons. This output was used to provide 100-MW input to a 30-cell X-band structure in which a 100-MV/m gradient was obtained. This system, using the higher klystron outputs expected in the future has the potential to deliver the 350 MW needed to obtain 100 MV/m gradients in the 1.8-m NLC prototype structure. This note describes the timing, triggering, and phase coding used in the two-klystron experiment, and the expected and measured net-work response to three- or two-stage modulation.
Date: April 1, 1993
Creator: Farkas, Z. D.; Lavine, T. L.; Menegat, A.; Vlieks, A. E.; Wang, J. W. & Wilson, P. B.
Partner: UNT Libraries Government Documents Department

Digital electronics for the inclusion of shower max and preshower wire data in the CDF second-level trigger

Description: As part of the upgrade program at CDF, electronics has been built to bring the shower max (CES) and preshower (CPR) data into the trigger at level 2. After each crossing, 384 bits from shower max and 192 from the preshower wires are latched. Data from tracks are bussed to this module to provide the wire address and momentum which are then successively compared to the wire data in large look-up tables. Approximately 50 nanoseconds is required to determine a match, write the results in FIFO, and make the results available to track memory. Monte Carlo analysis has indicated that an increase in efficiency of a factor of three in triggering on b decays will be achieved with this hardware.
Date: July 1, 1993
Creator: Dawson, J. W.; Byrum, K. L.; Haberichter, W. N.; Nodulman, L. J.; Wicklund, A. B.; Turner, K. J. et al.
Partner: UNT Libraries Government Documents Department

Calibration techniques for a fast duo-spectrometer

Description: The authors have completed the upgrade and calibration of the Ion Dynamics Spectrometer (IDS), a high-speed Doppler duo-spectrometer which measures ion flow and temperature in the MST Reversed-field Pinch. This paper describes an in situ calibration of the diagnostic`s phase and frequency response. A single clock was employed to generate both a digital test signal and a digitizer trigger thus avoiding frequency drift and providing a highly resolved measurement over the system bandwidth. Additionally, they review the measurement of the spectrometer instrument function and absolute intensity response. This calibration and subsequent performance demonstrate the IDS to be one of the fastest, highest throughput diagnostics of its kind. Typical measurements are presented.
Date: June 1, 1996
Creator: Chapman, J.T. & Den Hartog, D.J.
Partner: UNT Libraries Government Documents Department

Silicon Tracking Upgrade at CDF

Description: The Collider Detector at Fermilab (CDF) is scheduled to begin recording data from Run II of the Fermilab Tevatron in early 2000. The silicon tracking upgrade constitutes both the upgrade to the CDF silicon vertex detector (SVX II) and the new Intermediate Silicon Layers (ISL) located at radii just beyond the SVX II. Here we review the design and prototyping of all aspects of these detectors including mechanical design, data acquisition, and a trigger based on silicon tracking.
Date: April 1, 1998
Creator: Kruse, M. C.
Partner: UNT Libraries Government Documents Department

Photoconductive semiconductor switches: Laser Q-switch trigger and switch-trigger laser integration

Description: This report provides a summary of the Pulser In a Chip 9000-Discretionary LDRD. The program began in January of 1997 and concluded in September of 1997. The over-arching goal of this LDRD is to study whether laser diode triggered photoconductive semiconductor switches (PCSS) can be used to activate electro-optic devices such as Q-switches and Pockels cells and to study possible laser diode/switch integration. The PCSS switches we used were high gain GaAs switches because they can be triggered with small amounts of laser light. The specific goals of the LDRD were to demonstrate: (1) that small laser diode arrays that are potential candidates for laser-switch integration will indeed trigger the PCSS switch, and (2) that high gain GaAs switches can be used to trigger optical Q-switches in lasers such as the lasers to be used in the X-1 Advanced Radiation Source and the laser used for direct optical initiation (DOI) of explosives. The technology developed with this LDRD is now the prime candidate for triggering the Q switch in the multiple lasers in the laser trigger system of the X-1 Advanced Radiation Source and may be utilized in other accelerators. As part of the LDRD we developed a commercial supplier. To study laser/switch integration we tested triggering the high gain GaAs switches with: edge emitting laser diodes, vertical cavity surface emitting lasers (VCSELs), and transverse junction stripe (TJS) lasers. The first two types of lasers (edge emitting and VCSELs) did activate the PCSS but are harder to integrate with the PCSS for a compact package. The US lasers, while easier to integrate with the switch, did not trigger the PCSS at the US laser power levels we used. The PCSS was used to activate the Q-switch of the compact laser to be used in the X-1 Advanced Radiation Source.
Date: December 1, 1997
Creator: Loubriel, G.M.; Mar, A.; Hamil, R.A.; Zutavern, F.J. & Helgeson, W.D.
Partner: UNT Libraries Government Documents Department

A VXI-based, integrated system of beam position monitoring and rf measuremednt for the Advanced Photon Source (APS) linear accelerator

Description: A combined system of beam position monitoring and rf measurement has been implemented at the APS S-band linear accelerator (linac). The linac is subdivided into five sectors and each sector is comprised of a klystron and associated accelerating structures. The instrumentation for each sector is located, together with its processor, in two VM mainframes. This system has operated successfully for more than a year.
Date: June 1, 1995
Creator: Grelick, A.E.; Arnold, N.; Clifft, B.; Fuja, R.; Ko, K. & White, M.
Partner: UNT Libraries Government Documents Department

A first level tracking trigger for the upgraded D-Zero detector

Description: A fast tracking trigger system based on a new scintillating fiber tracker is being built for the upgraded D0 detector for the Collider Run II at Fermilab. This fiber tracker trigger provides a first level hardware trigger, supplies track seeds for the first level muon trigger and for the second level trigger. The physics requirements and the corresponding algorithms for the hardware trigger will be described. Particularly, PLD (Programmable Logical Device) chips are used to implement our trigger algorithms to achieve pattern recognition from scintillating fiber hits and to format that information for delivery to other trigger systems. Detector trigger efficiency studies will also be presented.
Date: May 11, 1999
Creator: F. Borcherding, S. Grunendahl, M. Johnson, M. Martin, J. Olsen and K.Yip
Partner: UNT Libraries Government Documents Department