The results of the CMS tracker alignment analysis are presented using the data from cosmic tracks, optical survey information, and the laser alignment system at the Tracker Integration Facility at CERN. During several months of operation in the spring and summer of 2007, about five million cosmic track events were collected with a partially active CMS Tracker. This allowed us to perform first alignment of the active silicon modules with the cosmic tracks using three different statistical approaches; validate the survey and laser alignment system performance; and test the stability of Tracker structures under various stresses and temperatures ranging from +15 °C to −15 °C. Comparison with simulation shows that the achieved alignment precision in the barrel part of the tracker leads to residual distributions similar to those obtained with a random misalignment of 50 (80) μm RMS in the outer (inner) part of the barrel.

In March 2007 the assembly of the Silicon Strip Tracker was completed at the Tracker Integration Facility at CERN. Nearly 15% of the detector was instrumented using cables, fiber optics, power supplies, and electronics intended for the operation at the LHC. A local chiller was used to circulate the coolant for low temperature operation. In order to understand the efficiency and alignment of the strip tracker modules, a cosmic ray trigger was implemented. From March through July 4.5 million triggers were recorded. This period, referred to as the Sector Test, provided practical experience with the operation of the Tracker, especially safety, data acquisition, power, and cooling systems. This paper describes the performance of the strip system during the Sector Test, which consisted of five distinct periods defined by the coolant temperature. Significant emphasis is placed on comparisons between the data and results from Monte Carlo studies.

The subsystems of the CMS silicon strip tracker were integrated and commissioned at the Tracker Integration Facility (TIF) in the period from November 2006 to July 2007. As part of the commissioning, large samples of cosmic ray data were recorded under various running conditions in the absence of a magnetic field. Cosmic rays detected by scintillation counters were used to trigger the readout of up to 15% of the final silicon strip detector, and over 4.7 million events were recorded. This document describes the cosmic track reconstruction and presents results on the performance of track and hit reconstruction as from dedicated analyses.

The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is housed in a unit, called {\it PMT-Block}. The PMT-Block is a compact instrument comprising a light mixer, a PMT together with its divider and a {\it 3-in-1} card, which provides shaping, amplification and integration for the signals. This instrument needs to be qualified before being assembled on the detector. A PMT-Block test bench has been developed for this purpose. This test bench is a system which allows fast, albeit accurate enough, measurements of the main properties of a complete PMT-Block. The system, both hardware and software, and the protocol used for the PMT-Blocks characterisation are described in detail in this report. The results obtained in the test of about 10000 PMT-Blocks needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile Calorimeter are also reported.

Inelastic nuclear collisions of hadrons incident on silicon sensors can generate secondary highly ionising particles (HIPs) and deposit as much energy within the sensor bulk as several hundred minimum ionising particles. The large signals generated by these 'HIP events' can momentarily saturate the APV25 front-end readout chip for the silicon strip tracker (SST) sub-detector of the compact muon solenoid (CMS) experiment, resulting in deadtime in the detector readout system. This paper presents studies of this phenomenon through simulation, laboratory measurements and dedicated beam tests. A proposed change to a front-end component to reduce the APV25 sensitivity to HIP events is also examined. The results are used to infer the expected effect on the performance of the CMS SST at the future large hadron collider. The induced inefficiencies are at the percent level and will have a negligible effect on the physics performance of the SST.

The trigger used for the collection of the samples of K→ππ decays in the NA48 experiment at CERN uses a novel pipeline design in order to satisfy the demanding specifications of a high rate kaon beam. The trigger algorithms, architecture and performance are described. * Present address: Dipartimento di Fisica dell'Universit\`a di Roma ``La Sapienza'', I-00185 Roma, Italy .

The “neutral” trigger system for the selection of K0P2p0P4c decays of the NA48 CP-violation experiment is described. The trigger system has been implemented in a 40MHz “dead-time free” pipeline to allow large rate reduction and high-trigger efficiency. The trigger decision is based on the information from 13 340 cells of the electro-magnetic calorimeter. Every 25 ns the energy, the centre of gravity, the kaon lifetime and the number of peaks in calorimeter projections are calculated in the trigger. The pipeline system is described and the performance of the trigger during the 1997 data-taking period is discussed. ( 1998 Published by Elsevier Science B.V. All rights reserved. *Corresponding author. E-mail: gunther.fischer@cern.ch. 1The NA48 Collaboration is: Cagliari, Cambridge, CERN, Dubna, Edinbourgh, Ferrara, Firenze, Mainz, Orsay, Perugia, Pisa, Saclay, Siegen, Torino, Vienna, Warsaw. 2On leave from Institute of Nuclear Physics, Cracow, Poland.

The “neutral” trigger system for the selection of K0→2π0→4γ decays of the NA48 CP-violation experiment is described. The trigger system has been implemented in a 40MHz “dead-time free” pipeline to allow large rate reduction and high-trigger efficiency. The trigger decision is based on the information from 13340cells of the electro-magnetic calorimeter. Every 25ns the energy, the centre of gravity, the kaon lifetime and the number of peaks in calorimeter projections are calculated in the trigger. The pipeline system is described and the performance of the trigger during the 1997 data-taking period is discussed.

A first level trigger system based on a 40 MHz digital pipeline has been developed for the CERN NA48 [1] experiment, aiming at measuring CP violation in K-0 --> 2 pi decays.The outputs of the 13340 cells of the 10 m(3) liquid krypton calorimeter are summed into 64 X and 64 Y projection strips and continuously digitised with 40 MHz FADCs.This information is used to reconstruct at each clock cycle and for the two calorimeter projections, the number of clusters, the impact time of each of them (with a precision of about 3 ns), their total energy and the first and second moments of the energy distribution.Based on the quantities listed above, a programmable look-up table system subsequently computes online the longitudinal position of the kaon decay vertex and performs an event selection.The system is described.

The ALEPH silicon vertex detector is the first detector operating in a colliding beam environment that uses silicon strip detectors which provide readout on both sides and hence a three-dimensional point measurement for the trajectory of charged particles. The detector system was commissioned successfully at the e+e− collider LEP at the research centre CERN, Switzerland, during the year 1991 while taking data at the Z0 resonance. The achieved spatial resolution of the complete 73 728 channel device (intrinsic plus alignment) is 12 μm in the r-f view and 12 μm in the z view. The design and construction of the entire detector system are discussed in detail and the experience gained in running the detector will be described with special emphasis on the uses of this novel tracking device for the physics of short-lived heavy particles produced in the decays of the Z0 resonance.

We report the results of measurements performed using a tracking detector based on 835 μm scintillating fibres read out by two position-sensitive photomultipliers. A six-layer hodoscope consisting of 1.2 m long fibres has been built and tested using cosmic rays. Subsequently, two such hodoscopes have been assembled and tested using a hadron beam at the CERN PS. The efficiency per plane is found to be about 70% and the point resolution about 130 μm. The signal-to-noise ratio is about 2.4 and is dominated by crosstalk in the position-sensitive photomultipliers.

We have studied the properties of electromagnetic shower counters made of scintillator and lead tiles of different thickness. Light collection is achieved by wavelength shifting fibres sparse in the body of the calorimeter. The counters were tested in a beam of electrons, pions and muons with energies between 2 and 8 GeV. We report here the final results of the test. The energy resolution is in good agreement with what is expected from the sampling fraction, i.e. sigma/E = 0.07/root E, the non uniformity of the response is less than 1% at the centre of a counter and 7 in the boundaries between modules, and the pi/e contamination is at the level of a few 10(-3). Performance of the calorimeter with readout systems able to operate in magnetic field is also reported.

A large system of silicon strip detectors with double sided readout has been successfully commissioned over the course of the last year at the e+e− collider LEP. The readout of this 73 728 channel system is performed with custom designed VLSI charge sensitive amplifier chips (CAMEX64A). An overall point resolution of 12 μm on both sides has been acheived for the complete system. The most important difficulties during the run were beam losses into the detector, and a chemical agent deposited onto the electronics; however, the damage from these sources was understood and brought under control. This and other results of the 1991 data-taking run are described with special emphasis on the operational experience.