Search

Abstract: We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the detector. The first two studies measure the tracking efficiency of a charged particle using and initial state radiation decays. The third uses the decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of particles. The first section also examines the stability of the measurements vs. running periods. [Copyright &y& Elsevier]

Abstract: A new Silicon Detector Telescope has been constructed and installed within the experimental facility of the A1 collaboration at Mainz Microtron, with the goal to detect low-energy protons. It consists of seven silicon layers for energy and angle measurement and a plastic scintillator for triggering purposes. The detector subtends a solid angle up to 88msr, depending on the distance from the target and covers the proton kinetic energy range of 25–41 MeV with the mean energy resolution , operating at 500kHz. Digital signal processing methods applied for energy reconstruction have been important for keeping the acceptable energy resolution at high counting rates. The Silicon Detector Telescope has been successfully used in double and triple coincidence measurements along with the magnetic spectrometers of the A1 collaboration. [Copyright &y& Elsevier]

A cryogenic supersonic gas jet target was developed for the MAGIX experiment at the high-intensity electron accelerator MESA. It will be operated as an internal, windowless target in the energy-recovering recirculation arc of the accelerator with different target gases, e.g., hydrogen, deuterium, helium, oxygen, argon, or xenon. Detailed studies have been carried out at the existing A1 multi-spectrometer facility at the electron accelerator MAMI. This paper focuses on the developed handling procedures and diagnostic tools, and on the performance of the gas jet target under beam conditions. Considering the special features of this type of target, it proves to be well suited for a new generation of high-precision electron scattering experiments at high-intensity electron accelerators. [ABSTRACT FROM AUTHOR]

The light collection of several fiber configurations embedded in a box-shaped plastic scintillating counter was studied by scanning with minimum ionizing electrons. The light was read out by silicon photomultipliers at both ends. The light yield produced by the 855-MeV beam of the Mainz Microtron showed a strong dependence on the transverse distance from the beam position to the fibers. The observations were modeled by attributing the collection of indirect light inside of the counter and of direct light reaching a fiber to the total light yield. The light collection with fibers was compared to that of a scintillating counter without fibers. These studies were carried out within the development of plastic scintillating detectors as an active veto system for the DarkMESA electron beam-dump experiment that will search for light dark matter particles in the MeV mass range. [ABSTRACT FROM AUTHOR]

The broad physics program of the KLOE experiment is based on the high event rate at the Frascati φfactory, and calls for an up-to-date system for data acquisition and processing. In this review of the KLOE offline environment, the architecture of the data-processing system and the programs developed for data reconstruction and Monte Carlo simulation are described, as well as the various procedures used for data handling and transfer between the different components of the system. [Copyright &y& Elsevier]

The Data Acquisition system for the KLOE experiment, presently running at the Laboratori Nazionali di Frascati DAΦNE collider, has been designed to sustain an acquisition throughput of 50 Mbyte/s for an event rate of 10 kHz. Its two major components are the front end data readout, based on custom buses, and a complex network of computers and storage devices hosting a set of distributed processes. The end result is a seamless data transport from the readout system to the storage library, accompanied by concurrent on line calibrations and data quality control. [Copyright &y& Elsevier]

We present the design of the trigger system for the KLOE experiment at the Frascati φ-factory DAΦNE. The detector consists of a large-volume drift chamber and a calorimeter both immersed in a 0.52 T solenoidal field. The trigger, structured with a first- and a second-decision level, is based on the multiplicity of energy deposits in the calorimeter and of hits in the drift chamber. The selection criteria are described and the efficiency for detecting φ decays is evaluated using data. [Copyright &y& Elsevier]

The quadrupole tile calorimeters of KLOE (QCAL) are two compact detectors placed close to the interaction point and surrounding the focusing quadrupoles. Their purpose is to increase the hermeticity of KLOE calorimetry. Each QCAL consists of a sampling structure of lead plates and scintillator tiles with wavelength shifter (WLS) fibers and mesh photomultiplier readout arranged in 16 azimuthal sectors. The arrangement of WLS fibers allows the measurement of the longitudinal position of the showers from time of flight. In this paper we describe the QCAL design and assembly and present preliminary results obtained with both cosmic rays and photons from KL decays. The time and energy calibration procedures are also discussed in detail. [Copyright &y& Elsevier]

A study of the detector response of PbF 2 crystals and three different types of lead glass blocks to electrons from a 14-MeV beam of the Mainz Microtron MAMI is presented. For the first time, signal height, signal width, and homogeneity of the response of these Cherenkov radiators were determined for energies between 10 and 14 MeV. To complement the beam tests, optical properties of the materials, in particular measured transmittances in the near UV and visible spectrum, were studied. The measured detector responses were also compared to Monte Carlo simulations of energy-loss, light production, transport, and detection. These Cherenkov radiators are considered as active material of a low-energy calorimeter for the detection of light dark matter particles recoiling off electrons behind the beam-dump of the Mainz Energy Recovering Superconducting Accelerator MESA. [ABSTRACT FROM AUTHOR]

At the Institute for Nuclear Physics in Mainz the new electron accelerator MESA will go into operation within the next years. The high-power beam dump of the P2 experiment is ideally suited for a parasitic dark sector experiment — DarkMESA. In the first stage 1,000 high density Cherenkov radiators from a previous experiment will be used. The experiment is studied with a simulation based on MadGraph and Geant4. The simulation includes an optical photon study, where the response of possible calorimeter materials – PbF 2 , BGO, the Pb glasses SF5, SF6 and SF57HTultra from Schott – was investigated. The simulation outcomes are compared with the results of prototypes tested at the Mainz Microtron (MAMI) with 6 to 14 MeV electrons. The exclusion limits for PbF 2 are shown, together with the limits obtained incrementally adding Pb glass blocks in two successive phases. The current development status of a prototype detector will be described, including a concept for a cosmics veto system. [ABSTRACT FROM AUTHOR]