V. Millucci

A Silicon Array for Cosmic-Ray Composition Measurements in CALET

The CALorimetric Electron Telescope (CALET) mission is proposed for a long exposure observation of high energy cosmic rays and gamma radiation, taking advantage of the JEM-EF facility on the International Space Station. The instrument is optimized for the search of nearby sources of acceleration of cosmic ray electrons in the TeV energy range. Its large collection power also allows for precision studies of the elemental composition of VHE nuclei and of their spectral features. The charge identification of the incoming particle is performed by a double-layered array of pixelated silicon sensors, covering a seamless sensitive area of the order of 1 m 2 . The conceptual design of the array and its front-end electronics are presented.

Apparent Solubility and Dissolution Profile at Non-Sink Conditions as Quality Improvement Tools

Stefania Petralito1,*, Iacopo Zanardi2,*, Adriana Memoli1, M. Cristina Annesini3, Vincenzo Millucci4 and Valter Travagli2 1Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universita di Roma, 2Dipartimento Farmaco Chimico Tecnologico, Universita degli Studi di Siena, 3Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Universita di Roma, 4Dipartimento di Fisica, Universita degli Studi di Siena, Italy

Study of a new scatter rejection technique in digital radiography

Abstract A new technique for digital mammography based on the use of a collimator and an anti-scatter grid coupled with a mosaic detector has been studied with a Monte Carlo program. The simulation, with a low-energy spectrum X-ray beam and a breast phantom, provides a quantitative assessment of the capability of the method to reduce the physical background of the image due to scattering in the body, without introducing image artifacts. With minor modifications to the existing X-ray facilities, the method could also be applied to area detectors. To verify the results of the simulation, an experimental setup based on a CCD camera coupled via a fiber optic plate to a CsI(Tl) scintillator is under test.

A low-power high dynamic range front-end ASIC for imaging calorimeters

High granularity calorimeters with shower imaging capabilities require dedicated front-end electronics. The ICON_4CH and VA4_PMT chip-set is suitable for very high dynamic range systems with strict noise requirements. The ICON-4CH is a 4 channel input, 12 channel output ASIC designed for use in a multi-anode photomultiplier system with very large dynamic range and low-noise requirements. Each of the four input signals to the ASIC is split equally into three branches by a current conveyor. Each of the three branches is scaled differently: 1:1, 1:8 and 1:80. The signal is read out by a 12 channel low noise / low power high dynamic range charge sensitive preamplifiershaper circuit (VA4-PMT chip), with simultaneous sampleand-hold, multiplexed analog read-out, calibration facilities. Tests performed in our lab with a PMT are reported in terms of linearity, dynamic range and cross-talk of the system.

Drainage pattern of commercial ophthalmic gels: an innovative method of evaluation

The feasibility of an innovative in vitro technique for providing information about the drainage pattern of certain commercially available ophthalmic gels has been investigated. The samples showed qualitatively and/or quantitatively different formulations in terms of either the gelforming agents or the other auxiliary substances. Both torsional oscillation and sine-wave vibro viscometers have been employed during the experiments. The drainage behavior of the gels in systems that essentially differ in both probe adhesiveness and tonicity level of the dispersing media have been estimated. The results obtained revealed different patterns of drainage over time among the various samples. In conclusion, the technique developed offers a viable means of characterizing gels in terms of consistency, adhesion and clearance and it appears to be a useful tool for estimating the surface residence times of gels.

Design and characterization of a double-layered silicon charge detector for cosmic ray measurements in CALET

CALET (CALorimetric Electron Telescope) is a space instrument to explore a new frontier at higher energies for the cosmic-rays (electrons, gamma rays and heavy nuclei) and to search for dark matter.1 This mission is designed for a long exposure observation on the external JEM-EF facility aboard the International Space Station. It is optimized for the search of nearby sources of acceleration of cosmic ray electrons in the TeV energy range and gamma rays up to several TeV range. It can also extend the available data on cosmic ray composition and on secondaryto-primary ratios to higher energies allowing to discriminate among different propagation models and to derive the acceleration spectra at the source. An accurate measurement of the charge of the incoming particle is performed in CALET by a double-layered array of pixelated silicon sensors (Silicon Array or SIA), covering a seamless sensitive area of the order of 0.3 m2 and providing single-element identification up to Fe and above. The design of SIA instrument and its characterization are presented.

CAET Mission on the ISS

We are developing the CALorimetric Electron Telescope, CALET, mission for the Japanese Experiment Module Exposed Facility, JEM-EF, of the International Space Station. Major scientific objectives are to search for the nearby cosmic ray sources and dark matter by carrying out a precise measurement of the electrons in 1 GeV - 20 TeV and gamma rays in 20 MeV - several 10 TeV. CALET has a unique capability to observe electrons and gamma rays over 1 TeV since the hadron rejection power can be larger than 105 and the energy resolution better than a few % over 100 GeV. The detector consists of an imaging calorimeter with scintillating fibers and tungsten plates and a total absorption calorimeter with BGO scintillators. CALET has also a capability to measure cosmic ray H, He and heavy ionsi up to 1000 TeV. It also will have a function to monitor solar activity and gamma ray transients. The phase A study has started on a schedule of launch in 2013 by H-II Transfer Vehicle (HTV) for 5 year observation.

Low-energy beam test results of a calorimeter prototype for the CREAM experiment

CREAM (Cosmic Ray Energetics And Mass) is an experiment under construction for a direct measurement of high energy cosmic rays (1012 to > 5 · 1014 eV) over the elemental range from proton to iron. The first flight of CREAM is intended to demonstrate the new Ultra Long Duration Balloon (ULDB) capability under development by NASA. A prototype of a tungsten-SciFi imaging calorimeter designed for CREAM has been tested at CERN with electron beam energies ranging from 5 to 100 GeV. Although the calorimeter module is optimized for cosmic-ray spectral measurements in the multi-TeV region, the response of its electromagnetic section to low energy electrons has been studied with this dedicated prototype. Results show good agreement with the expected behaviour in terms of linearity and energy resolution.

Proof-of-principle apparatus for scattering suppression in digital mammography

A low-noise CCD coupled to a structured CsI(Tl) scintillator via a fiber optic plate was operated as X-ray detector for digital mammography. The imaging capabilities of the device were measured in terms both of spatial resolution (MTF) and of noise properties (DQE, NPS). The detector was characterized using a standard mammographic tube with and without the coupling to a pair of anti-scatter projective grids. Breast phantom images were collected and compared to a MonteCarlo simulation of the apparatus. Contrast enhancement was achieved by using the anti-scatter grids.