Two standard commercial flashlamp-pumped Nd:YAG lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to fifteen 2 J Q-switched pulses (1064 nm) at repetition rates ...1–12.5 kHz. Variable pulse-width drive (0.15–0.39 ms) of the flashlamps is accomplished by IGBT (insulated gate bipolar transistor) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to study the dynamic evolution of the electron temperature.
Large CMS cathode strip chambers: design and performance Acosta, D; Apollinari, G; Blomquist, J ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2000, Letnik:
453, Številka:
1
Journal Article
Recenzirano
Presented are the main design features of the large Cathode Strip Chambers (CSCs) for the CMS Endcap Muon System as well as the performance results obtained with the two full-scale 3.4×1.5 m
2 ...six-plane prototypes. The prototype performance was within the baseline requirements: (a) higher than 99% efficiency of muon track finding at the trigger level with more than 92% probability for bunch crossing identification and better than 2
mm spatial resolution, and (b) better than 150
μm spatial resolution in off-line.
The ZEUS calorimeter first level trigger Smith, W.H.; Ali, I.; Behrens, B. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/1995, Letnik:
355, Številka:
2
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The design of the ZEUS Calorimeter First Level Trigger (CFLT) is presented. The CFLT utilizes a pipelined architecture to provide trigger data for a Global First Level Trigger decision 5 μs after ...each beam crossing, occurring every 96 ns. The charges from 13 K phototubes are summed into 1792 trigger tower pulseheights which are digitized by flash ADCs. The digital values are linearized, stored and used for sums and pattern tests. Summary data is forwarded to the Global First Level Trigger for each crossing 2 μs after the crossing occurred. The CFLT determines the total energy, the total transverse energy, the missing energy, and the energy and number of isolated electrons and muons. It also provides information on the electromagnetic and hadronic energy deposited in various regions of the calorimeter. The CFLT has kept the experimental trigger rate below ≈ 200 Hz at the highest luminosity experienced at HERA. Performance studies suggest that the CFLT will keep the trigger rate below 1 kHz against a rate of proton-beam gas interactions on the order of the 100 kHz expected at design luminosity.
Internal time-resolved measurement of magnetic field and electron temperature in low-field (≤ 1 T) plasmas is a difficult diagnostic challenge. To meet this diagnostic challenge in the Madison ...Symmetric Torus reversed-field pinch, two techniques are being developed: 1) spectral motional Stark effect (MSE) and 2) Fast Thomson scattering. For spectral MSE, the entire Stark-split Hα spectrum emitted by hydrogen neutral beam atoms is recorded and analyzed using a newly refined atomic emission model. A new analysis scheme has been developed to infer both the polarization direction and the magnitude of Stark splitting, from which both the direction and magnitude of the local magnetic field can be derived. For Fast Thomson scattering, two standard commercial flashlamp-pumped Nd:YAG lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to fifteen pulses at repetition rates 1-12.5 kHz, thus enabling recording of the dynamic evolution of the electron temperature profile and electron temperature fluctuations. To further these capabilities, a custom pulse-burst laser system is now being commissioned. This new laser is designed to produce a burst of laser pulses at repetition frequencies 5-250 kHz.
The ZEUS calorimeter first level trigger Silverstein, S.; Ali, I.; Behrens, B. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/1995, Letnik:
360, Številka:
1-2
Journal Article
Recenzirano
An overview of the ZEUS calorimeter first level trigger is presented. The CFLT uses a pipelined architecture to accept and analyze calorimeter data for every 96 ns beam crossing interval. PMT signals ...are combined by analog electronics into electromagnetic and hadronic sums for 896 trigger towers. The analog sums are then digitized and analyzed. The CFLT determines the total, transverse, and missing transverse energy, identifies isolated electrons and muons, and sums energies in programmable subregions. Calculations are performed in 96 ns steps, and new data are accepted for every beam crossing. Trigger data are forwarded to the global first level trigger (GFLT) after 2 μs, allowing a GFLT accept to be issued 5 μs after the beam crossing which produced the event. Important features of the CFLT include a 12-bit effective dynamic range, extensive use of memory lookup tables for trigger calculations, fast pattern searches for isolated leptons, and low electronics noise. During the 1993 HERA run, the CFLT reduced a 50 kHz background rate to around 100 Hz.
The electronics for the regional calorimeter trigger (RCT) of the Compact Muon Solenoid experiment (CMS) at the Large Hadron Collider (LHC) have been produced and tested, and are being integrated ...with the experiment at CERN. The RCT hardware consists of 18 double-sided crates containing custom boards, ASICs, and backplanes all running at 160 MHz frequency. The RCT receives 8 bit energies and a data quality bit on 1008 4times1.2 Gbaud copper links from the hadron calorimeter (HCAL) and the electromagnetic calorimeter (ECAL) trigger primitive generators (TPGs), accepting new events every 25 ns. RCT processing determines the jet region energies, and, sorted isolated and non-isolated electromagnetic objects, which are sent to the CMS global calorimeter trigger (GCT) for further processing. Before installation, both self-tests, using RCT jet capture card, and integration tests with TPG and GCT systems were performed. Their results of these tests and the RCT installation experience are described.
A description is given of a number of time-to-digital converters (TDCs) that have been built with 1-ns resolution. They can run for long times and be used with triggers that arrive immediately or ...several microseconds after the event of interest. The TDCs are very linear, with a standard deviation of less than 0.53 ns. The discussion covers the timing method, tolerances, multiplexing, Fastbus implementation, the clock-clear board, fabrication, and performance.< >
The Compact Muon Solenoid (CMS) calorimeter regional trigger system is designed to detect signatures of isolated and non-isolated electrons/photons, jets, /spl tau/-leptons, and missing and total ...transverse energy using a deadtimeless pipelined architecture. This system contains 18 crates of custom-built electronics, including a backplane, boards, links and Application-Specific Integrated Circuits (ASICs). We present results from testing a completely instrumented and fully functional preproduction system. We also describe the production testing of the final system, including the custom software necessary to automate the process of testing a large quantity of high-speed and dense electronics.
The Compact Muon Solenoid (CMS) calorimeter regional trigger system is
designed to detect signatures of isolated and non-isolated electrons/photons,
jets, ?-leptons, and missing and total transverse ...energy using a deadtimeless
pipelined architecture. This system contains 18 crates of custom-built
electronics. The pre-production prototype backplane, boards, links and
Application-Specific Integrated Circuits (ASICs) have been built and their
performance is characterized.
Over 5,000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy ...neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-inch diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resolution, late pulses and afterpulses are characterized. Because the PMTs are relatively large, the cathode sensitivity uniformity was measured. The absolute photon detection efficiency was calibrated using Rayleigh-scattered photons from a nitrogen laser. Measured characteristics are discussed in the context of their relevance to IceCube event reconstruction and simulation efforts.
PDF
