The measurements foreseen in the COMPASS experiment at CERN, require high resolution tracking detectors, with low radiation length and high rate capability. For this purpose we have developed and ...optimized a gaseous microstrip detector ‘Micromegas’. Twelve planes with 1024 strips each, assembled in 3 stations of 4 views XYUV, have been operated with success in the summer of 2002 in the COMPASS environment. We describe here the performances and results obtained.
The beam and detector, used for the NA48 experiment, devoted to the measurement of
Re
(
ε
′
/
ε
)
, and for the NA48/1 experiment on rare
K
S
and neutral hyperon decays, are described.
We built and commissioned a new type of Compton polarimeter to measure the electron beam polarization at the Thomas Jefferson National Accelerator Facility (Virginia, USA). The heart of this ...polarimeter is a high-finesse monolithic Fabry–Pérot cavity. Its purpose is to amplify a primary 300 mW laser beam in order to improve the signal to noise ratio of the polarimeter. It is the first time that a high-finesse Fabry–Pérot cavity is enclosed in the vacuum of a particle accelerator to monitor the beam polarization by Compton polarimetry. The measured finesse and amplification gain of the cavity are
F=26
000
and
G=7300. The electron beam crosses this high-power photon source at an angle of 23 mrad in the middle of the cavity where the photon beam power density is estimated to be
0.85
MW/
cm
2
. We have used this facility during the HAPPEX experiment (April–July 1999) and we give a preliminary measurement of Compton scattering asymmetry.
This paper presents the algorithms and the architecture proposed for the upgrade of the level 1 calorimeter trigger for the D0 experiment. We describe the digital-signal-processing algorithm applied ...to individual trigger tower signals and the physics algorithms that process the complete array of trigger towers. We investigate the performance of these algorithms and justify our choices. We present the hardware architecture of the system designed to analyze the signals of the 2560 calorimeter trigger tower samples and construct trigger primitives in /spl sim/3 /spl mu/s at a rate of 7.57 MHz. We give a detailed description of the two prototype boards that are being built: the analog-to-digital converter and filter board (ADF) that performs the analog conversion and digital processing of 32 calorimeter channels, and the trigger algorithm board (TAB) designed to run the physics selection algorithms on one eighth of the 480 Gbit/s of data produced by the complete set of ADF boards.
The increase in instantaneous luminosity anticipated in Run IIb of the Tevatron collider at Fermilab requires increased background rejection capabilities from the trigger system of the DO detector. A ...set of upgrades is under way to improve triggering at level 1 in the calorimeter and tracker, and at level 2 in the silicon track trigger and software triggers. Reductions of up to a factor of ten on the rates of high transverse momentum triggers are anticipated with the upgrades described.
The charged trigger system of NA48 at CERN Anvar, S.; Bugeon, F.; Debu, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/1998, Volume:
419, Issue:
2-3
Journal Article
Peer reviewed
Open access
The NA48 charged trigger is a mixed hardware and software real-time processing system intended to detect the interesting configurations of K0 charged decays. It achieves real-time event building, ...track reconstruction and kinematics computation on drift chamber data at an event rate of 100kHz and within a maximum decision latency of 100μs. The system uses data driven, FPGA-based coordinate builders, a hardware event builder based on a crossbar switch, and a farm of up to 16 event processors for its software part. It has been installed and operated at CERN since 1995. After a description of the constraints and architecture of the various subsystems, the paper gives an account of the results and performance of the system based on the 1996/1997 runs. More specifically, the replacement of the present DSP-based implementation of the processing farm by RISC processors will be discussed.
High resolution drift chambers for the NA48 experiment at CERN Béderède, D; Chèze, J.B; De Beer, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/1995, Volume:
367, Issue:
1
Journal Article
Peer reviewed
We discuss construction details of large drift chambers for the NA48 experiment at CERN. Preliminary measurements on their performance are also presented.
The measurements in the COMPASS experiment at CERN require high-resolution tracking detectors, with low radiation length and high-rate capability. For this purpose we have developed and optimized a ...gaseous microstrip detector `Micromegas'. Twelve planes with 1024 strips each, assembled in 3 stations of 4 views XYUV, are now being operated with success in the COMPASS environment. We describe here the performances and results obtained.
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