G. Bencze

Extensive measurements have been made with pions, electrons and muons on four production wedges of the compact muon solenoid (CMS) hadron barrel (HB) calorimeter in the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics running at 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers in the HB. The energy dependent time slewing effect was measured and tuned for optimal performance.

The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. The analysis of the differences in calorimeter response to charged pions, kaons, protons and antiprotons and a detailed discussion of the underlying phenomena are presented. We also show techniques that apply corrections to the signals from the considerably different electromagnetic (EB) and hadronic (HB) barrel calorimeters in reconstructing the energies of hadrons. Above 5 GeV/c, these corrections improve the energy resolution of the combined system where the stochastic term equals 84.7±1.6% and the constant term is 7.4±0.8%. The corrected mean response remains constant within 1.3% rms.

The Compact Muon Solenoid (CMS) experiment prepares its Phase-2 upgrade for the high-luminosity era of the LHC operation (HL-LHC). Due to the increase of occupancy, trigger latency and rates, the full electronics of the CMS Drift Tube (DT) chambers will need to be replaced. In the new design, the time bin for the digitization of the chamber signals will be of around 1 ns, and the totality of the signals will be forwarded asynchronously to the service cavern at full resolution. The new backend system will be in charge of building the trigger primitives of each chamber. These trigger primitives contain the information at chamber level about the muon candidates position, direction, and collision time, and are used as input in the L1 CMS trigger. The added functionalities will improve the robustness of the system against ageing. An algorithm based on analytical solutions for reconstructing the DT trigger primitives, called Analytical Method, has been implemented both as a software C++ emulator and in firmware. Its performance has been estimated using the software emulator with simulated and real data samples, and through hardware implementation tests. Measured efficiencies are 96 to 98% for all qualities and time and spatial resolutions are close to the ultimate performance of the DT chambers. A prototype chain of the HL-LHC electronics using the Analytical Method for trigger primitive generation has been installed during Long Shutdown 2 of the LHC and operated in CMS cosmic data taking campaigns in 2020 and 2021. Results from this validation step, the so-called Slice Test, are presented.

We report on the response of a prototype CMS hadron calorimeter module to charged particle beams of pions, muons, and electrons with momenta up to 375GeV/c. The data were taken at the H2 and H4 beamlines at CERN in 1995 and 1996. The prototype sampling calorimeter used copper absorber plates and scintillator tiles with wavelength shifting fibers for readout. The effects of a magnetic field of up to 3 T on the response of the calorimeter to muons, electrons, and pions are presented, and the effects of an upstream lead tungstate crystal electromagnetic calorimeter on the linearity and energy resolution of the combined calorimetric system to hadrons are evaluated. The results are compared with Monte Carlo simulations and are used to optimize the choice of total absorber depth, sampling frequency, and longitudinal readout segmentation.

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E T measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS.

This document describes results obtained from the Link alignment system data recorded during the Compact Muon Solenoid (CMS) Magnet Test. A brief description of the system is followed by a discussion of the detected relative displacements (from micrometres to centimetres) between detector elements and rotations of detector structures (from microradians to milliradians). Observed displacements are studied as functions of the magnetic field intensity. In addition, the reconstructed positions of active element sensors are compared to their positions as measured by photogrammetry and the reconstructed motions due to the magnetic field strength are described.

Theoretical considerations and experimental measurements indicate the importance of charged hadron identification in the higher pT region (namely pT>10 GeV/c). Since the PID capability of the present ALICE experiment at LHC (CERN) is based on statistical methods at large transverse momenta, the construction of a new detector to improve the track by track PID capability is very much supported. This task can be fulfilled by a gaseous ring imaging Cherenkov (RICH) detector. However, high-pT events are very rare, thus to enrich the statistics of the rare high pT events in the recorded data sample the construction of a dedicated trigger unit for the RICH detector is strongly recommended. To select the high-pT events the basic idea is to detect the inclination of the charged particle trajectories in the ALICE magnetic field with respect to the direction of the collision point. If the inclination is smaller than a threshold, the transverse momentum of the propagating particle is larger than a certain value. A prototype chamber using Thick Gas Electron Multiplier layers was built to test the operation principle of the High-pT Trigger Detector. The prototype was tested at the CERN PS beam facility. We present results of the operation tests and data taking. Monte Carlo simulations in the ALIROOT framework are also performed in order to optimize the geometry and segmentation of the detector we present here. In this paper we summarizes our efforts to develop the High-pT Trigger Detector.

Magnet Cycles and Stability Periods of the CMS Experiment are studied with the Alignment Link System data recorded along the 2008–2013 years of operation. The motions of the mechanical structures due to the magnetic field forces are studied and the mechanical stability of the detector during the physics data taking periods is verified.

A study of the time required for the CMS detector to reach structural equilibrium once the magnetic field is ramped to its operational value of 3.8 T is presented. In addition, the results from a stability monitoring at 3.8 T over an eight-month period are given.

The central feature of the CMS Link alignment system is a network of Amorphous Silicon Position Detectors distributed throughout the muon spectrometer that are connected by multiple laser lines. The data collected during the years from 2008 to 2015 is presented confirming an outstanding performance of the photo sensors during more than seven years of operation. Details of the photo sensor readout of the laser signals are presented. The mechanical motions of the CMS detector are monitored using these photosensors and good agreement with distance sensors is obtained.

The CMS Muon Barrel Alignment system uses cameras mounted on 36 rigid MAB structures to monitor DT positions. During the 2010 and 2011 data-taking periods, 4 such MABs became inoperative. This study shows that the resulting loss of information does not cause a significant degradation of the reconstructed DT positions.

The CMS Muon Barrel Alignment system uses cameras mounted on 36 rigid MAB structures to monitor DT positions. During the 2010 and 2011 data-taking periods, 4 such MABs became inoperative. This study shows that the resulting loss of information does not cause a significant degradation of the reconstructed DT positions.

During the past years our group has built, calibrated, and finally installed all the components of the Muon Barrel Alignment System for the CMS experiment. This paper covers the results of the hardware commissioning, the full system setup and the connection to the CMS Detector Control System (DCS). The step-by-step operation of the system is discussed: from collecting the analog video signals and preprocessing the observed LED images, through controlling the front-end PCs, to forming the measurement results for the CMS DCS. The first measurement results and the initial experiences of the communication with the DCS are also discussed.

Az OTKA altal tamogatott kutatas ket teruletre bonthato. I. A BNL RHIC gyorsitojanak PHENIX kiserleteben a meresekben es a kiserleti adatok analiziseben valo reszvetel: Csoportunk a PHENIX kollaboracio tagjakent dolgozott, munkaja beepult a PHENIX kiserlet kozos eredmenyeibe. Nehany teruleten a csoport hozzajarulasa kulonosen jelentős volt. Igy kiemelendő a jet-elnyomas jelensegenek vizsgalata kulonboző energiaju nehezion utkozesekben illetve az elektreomagneses kalorimeterrel kapcsolatos szimulacios es kalibracios tevekenyseg. II. Reszvetel a CERN-i LHC CMS kiserletenek epiteseben, ezen belul a barrel muon kamrak helyzetmeghatarozo rendszerenek fejlesztese es letrehozasa: a palyazati időszak alatt megepitesre kerult a teljes rendszer, amely lehetőve teszi a CMS barrel muon spektrometeret alkoto 250 nagymeretű driftkamra helyzetenek meghatarozasat szubmillimeteres pontossaggal. | The research activity supported by the OTKA fund can be divided in two groups. I. Participation in the measurements and the physics analysis of the PHENIX experiment at the RHIC accelerator in BNL (USA): our group worked in close collaboration with other members of the experiment so its work was integrated in the common results of the whole collaboration. In some areas, however, the contribution was particularly significant. Two areas can be emphasized, the investigation of jet suppression in heavy ion collisions at different energies and the simulation and calibration of the electromagnetic calorimeter. II. Participation in the construction of the CMS experiment to be installed at the LHC accelerator (CERN, Switzerland), development and construction of the barrel muon position monitoring system: the full system has been completed during the period of the OTKA-support. It allowes us to determine the positions of 250 large-scale drift-chambers forming the barrel muon spectrometer with submillimeter accuracy.

The Muon Barrel Alignment system is based on the precise measurement of LED positions and signals of different sensors located in several predetermined places of the barrel. These data are collected by 36 PC/104 board computers. The board computers are organized in a network and controlled by a workstation, which communicates with the DCS system providing the precise status information of the barrel muon chambers. The aim of this paper is to describe the communication flow, the data hierarchy, the data structure, and the distribution of the tasks among the elements of the system. The first simulation and test results are also discussed.

The CMS detector system of the LHC will use gas filled Drift Tube Chambers to detect muons. The gas pressure has to be kept at a constant level in the chambers and this level has to be monitored. Different versions of electronic boards (PADC) have been developed to regularly read out the pressure sensors and to send the pressure data to the Detector Control System (DCS) of CMS. This paper presents the functional description of the different PADC boards, the setup used for testing their radiation hardness and the results of the irradiation tests.

This document presents an overview of the induced photocurrents in the Amorphous Silicon Position Detectors used in the network of diode lasers and photo sensors of the CMS Link alignment system recorded during its eleven years of operation. After a description of the sensors characteristics, the layout of the sensors network is discussed. The sensors are distributed throughout the muon spectrometer and connected by laser lines. The data used correspond to readout information obtained during some of the physics runs from 2008 to 2018.

For the precise measurement of the positions of the barrel muon chambers in the CMS detector, a Position Monitoring System has been developed. It comprises ~10000 LED lightsources, 600 active pixel sensor monochrome video cameras, 24 tilt and 72 temperature sensors, 36 PC/104 board computers and a master control workstation for controlling the system and collecting and analyzing the data received from the sensors and cameras.

Neutron irradiation tests were performed with broad spectrum p(18MeV)+Be neutrons (En =3.5MeV) to study the neutron induced alterations of COTS (Commercially available Off The Shelf) optical and opto-electronic components (LED light source, LED driver, microcontroller, video camera, optical lens) of the CMS Muon Barrel Alignment system. Results of the tests are presented in this paper.

Neutron and proton irradiation tests were performed to study the radiation induced alterations of COTS (Commercially available Off The Shelf) CMOS active pixel sensors at two facilities. The sensors will be used for the CMS Barrel Muon Alignment system. Results of the tests are presented in this paper.