P. S. Marrocchesi

A Measurement of the Space - Like Pion Electromagnetic Form-Factor

Abstract The pion form factor has been measured in the space-like q 2 region 0.014 to 0.26 (GeV/ c ) 2 by scattering 300 GeV pions from the electrons of a liquid hydrogen target. A detailed description is given of the apparatus, data analysis and corrections to the data. The mean square charge radius extracted from the data is model-dependent. We find that a form which includes a realistic description of the form factor phase gives a similar results to the naive pole form, and conclude 〈r 2 π 〉 = 0.438±0.008 fm 2 .

Electronic measurement of the lifetime of D± mesons

Abstract Charmed meson pairs have been photoproduced coherently on an active silicon target. Ninety-eight decays have been analyzed and the lifetime of charged Ds has been measured.

Calibration of field inhomogeneities in a time projection chamber with laser rays

Abstract We present some results on the use of a set of laser beams to monitor and to measure the systematic displacements of the electron drift trajectories in a Time Projection Chamber of large (0.6 m 3 ) dimensions.

CALET UPPER LIMITS on X-RAY and GAMMA-RAY COUNTERPARTS of GW151226

We present upper limits in the hard X-ray and gamma-ray bands at the time of the LIGO gravitational-wave event GW 151226 derived from the CALorimetric Electron Telescope (CALET) observation. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ~1 GeV up to 10 TeV with a field of view of ~2 sr. The CALET gamma-ray burst monitor (CGBM) views ~3 sr and ~2pi sr of the sky in the 7 keV - 1 MeV and the 40 keV - 20 MeV bands, respectively, by using two different scintillator-based instruments. The CGBM covered 32.5% and 49.1% of the GW 151226 sky localization probability in the 7 keV - 1 MeV and 40 keV - 20 MeV bands respectively. We place a 90% upper limit of 2 x 10^{-7} erg cm-2 s-1 in the 1 - 100 GeV band where CAL reaches 15% of the integrated LIGO probability (~1.1 sr). The CGBM 7 sigma upper limits are 1.0 x 10^{-6} erg cm-2 s-1 (7-500 keV) and 1.8 x 10^{-6} erg cm-2 s-1 (50-1000 keV) for one second exposure. Those upper limits correspond to the luminosity of 3-5 x 10^{49} erg s-1 which is significantly lower than typical short GRBs.

HIGH-RESOLUTION SILICON DETECTORS FOR COLLIDING BEAM PHYSICS

Abstract Resolution and linearity of the position measurement of Pisa multi-electrode silicon detectors are presented. The detectors are operated in slightly underdepleted mode and take advantage of their intrinsic resistivity for resistive charge partition between adjacent strips. 22 μm resolution is achieved with readout lines spaced 300 μm. Possible applications in colliding beam experiments for the detection of secondary vertices are discussed.

A Monolithic Germanium Target with 100 Microns Granularity for Life-Time Measurement of Charmed Particles

Describes the germanium monlithic detector and discusses its performance. The detector is a parallelepiped 5 x 5 x 20 mm in volume with 48 electrodes 20 mm long, 50 microns wide and spaced 50 microns one from the other deposited on one face. Presents a sketch of the detector and its working principle. To obtain a finer granularity, a telescope of 40 layers of silica was substituted with a target made out of a single block of germanium followed by a silicon telescope.

The spatial resolution of the ALEPH TPC

The present understanding of the factors which limit the rφ measurement accuracy of the ALEPH time projection chamber is outlined. The resolution for high-momentum tracks is shown to be dominated by the E × B and angular affects.

Gating in the ALEPH Time Projection Chamber

The ALEPH TPC at LEP will use a gating grid to prevent distortions caused by space charge buildup in its 2.2 m drift region. Sets of measurements have demonstrated the feasibility of a “synchronous ion trapping” mode of gating, which reduces the positive ion flux through the grid by more than two orders of magnitude. A novel mode of gating will be discussed which would permit static operation of the gate, thereby avoiding the complexity of switching between the open and closed states of the gate. This mode would rely on the dissimilar gate penetration properties of electrons and ions in the presence of a magnetic field, and it may also provide a way to partially compensate for the E × B effect at the sense wires. A combination of these different modes is proposed for the ALEPH TPC.

The CREAM Calorimeter: Performance In Tests And Flights

The Cosmic Ray Energetics And Mass (CREAM) balloon‐borne experiment, designed to directly measure cosmic‐ray particle energies from ∼1011 to ∼1015 eV, had two successful flights since December 2004, with a total duration of 70 days. The CREAM calorimeter is comprised of 20 layers of 1 radiation length (X0) tungsten interleaved with 20 active layers each made up of fifty 1 cm wide scintillating fiber ribbons. The scintillation signals are read out with multi pixel Hybrid Photo Diodes (HPDs), VA32‐HDR2/TA32C ASICs and LTC1400 ADCs. During detector construction, various tests were carried out using radioactive sources, UV‐LEDs, and particle beams. We will present results from these tests and show preliminary results from the two flights.

Energy calibration of CALET onboard the International Space Station

Abstract In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began to collect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1xa0GeV to 20xa0TeV with a very high resolution of 2% above 100xa0GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units. Each TASC readout channel must be carefully calibrated over the extremely wide dynamic range of CALET that spans six orders of magnitude in order to obtain a degree of calibration accuracy matching the resolution of energy measurements. These calibrations consist of calculating the conversion factors between ADC units and energy deposits, ensuring linearity over each gain range, and providing a seamless transition between neighboring gain ranges. This paper describes these calibration methods in detail, along with the resulting data and associated accuracies. The results presented in this paper show that a sufficient accuracy was achieved for the calibrations of each channel in order to obtain a suitable resolution over the entire dynamic range of the electron spectrum measurement.