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The Pamela apparatus will be launched at the end of 2002 on board of the Resurs DK Russian satellite. The tracking system, composed of six planes of silicon sensors inserted inside a permanent magnetic field was intensively tested during these last years. Results of tests have shown a good signal-to-noise ratio and an excellent spatial resolution, which should allow to measure the antiproton flux in an energy range from 80MeV up to 190 GeV. The production of the final detector modules is about to start and mechanical and thermal tests on the tracking tower are being performed according to the specifications of the Russian launcher and satellite.

The propagation of cosmic rays inside our galaxy plays a fundamental role in shaping their injection spectra into those observed at Earth. One of the best tools to investigate this issue is the ratio of fluxes for secondary and primary species. The boron-to-carbon (B/C) ratio, in particular, is a sensitive probe to investigate propagation mechanisms. This paper presents new measurements of the absolute fluxes of boron and carbon nuclei as well as the B/C ratio from the PAMELA space experiment. The results span the range 0.44-129 GeV/n in kinetic energy for data taken in the period 2006 July to 2008 March. �� 2014. The American Astronomical Society. All rights reserved.

After seven years of data taking in space, the experiment PAMELA is showing very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt. ?????? Owned by the authors, published by EDP Sciences, 2014.

The project of the two Silicon Drift Detector (SDD) layers of the ALICE Inner Tracking System is reviewed, with details on the barrel construction and on the front-end electronics. The results on the SDD spatial resolution are reported as obtained in the 2000 beam test from a whole drift region of the detector.

SD2000 is a new photon counting MCP based detector. It consists of a single MCP, coated with a suitable photocathode, closely coupled to a Silicon Drift Detector (SDD). The electron clouds generated by the MCP channels are accelerated by a strong electric field applied and proximity focussed on the SDD, that works as a position sensitive read-out detector. The SDD, developed by the INFN laboratories in Trieste, is a butterfly Silicon Drift Detector with no metal deposition on its cathodes. The absence of metallization in the sensitive zone of the chamber allows the electron clouds to penetrate uniformly into the active region of the detector and to be revealed. A suitable front-end amplifier, that works as a charge preamplifier and a bipolar shaper, has been developed starting from SPICE simulations and tested. A proto-type of the detector has been realized and tested and the first results have been achieved and compared with the expected best performances of the detector.

We report on a new measurement of the cosmic ray antiproton spectrum. The data were collected by the balloon-borne experiment CAPRICE98 which was flown on 28-29 May 1998 from Fort Sumner, New Mexico, USA. The experiment used the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas Ring Imaging Cherenkov (RICH) detector, a time-of-flight system, a tracking device consisting of drift chambers and a superconducting magnet and a silicon-tungsten calorimeter. The RICH detector was the first ever flown capable of mass-resolving charge-one particles at energies above 5 GeV. A total of 31 antiprotons with rigidities between 4 and 50 GV at the spectrometer were identified with small backgrounds from other particles. The absolute antiproton energy spectrum was determined in the kinetic energy region at the top of the atmosphere between 3.2 and 49.1 GeV. We found that the observed antiproton spectrum and the antiproton-to-proton ratio are consistent with a pure secondary origin. However, a primary component may not be excluded., Comment: 39 pages, 11 Postscript figures, uses AAS LATEX style; changes in sections 3.1.1, 3.3, 3.4 and 6, Figure 8 modified, 2 figures added, typos corrected

An imaging calorimeter has been designed and is being built for the PAMELA satellite-borne experiment. The physics goals of the experiment are the measurement of the flux of antiprotons, positrons and light isotopes in the cosmic radiation. The calorimeter is designed to perform a precise measurement of the total energy deposited, to reconstruct the spatial development of the showers (both in the longitudinal and in the transverse directions), and to measure the energy distribution along the shower itself. From this information, the calorimeter will identify antiprotons from a electron background and positrons in a background of protons with an efficiency of about 95% and a rejection power better than 10^-4. Furthermore, a self-trigger system has been implemented with the calorimeter that will be employed to measure high-energy (from about 300 GeV to more than 1 TeV) electrons. The instrument is composed of 22 layers of tungsten, each sandwiched between two "views" of silicon strip detectors (X and Y). The signals are read out by a custom VLSI front-end chip, the CR1.4P, specifically designed for the PAMELA calorimeter, with a dynamic range of 7.14 pC or 1400 mip (minimum ionizing particle). We report on the simulated performance and prototype design., Comment: 26 pages, 19 figures, elsart LATEX style, submitted to Nucl. Instrum. and Meth

CAPRICE98 is a superconducting magnetic spectrometer, equipped with a gas RICH and a silicon calorimeter, launched from Ft. Sumner (USA), on the 28th of May 1998, by the WiZard collaboration. For the first time a gas RICH detector flew together with a silicon electromagnetic calorimeter, allowing mass resolved antiprotons, with E>18 GeV, to be detected. The detector configuration was completed by a time of flight for particle identification, and a set of three drift chambers for rigidity measurement. The science objectives are the study of antimatter in cosmic rays and the cosmic ray composition in the atmosphere with special focus on muons.

We report the results of the "rst beam test of one of the very large area silicon drift detector prototypes produced for the ALICE Inner Tracking System. The main parameters describing the overall detector performance are discussed, including data on e$ciency, charge collection and linearity of the detector. 2001 Elsevier Science B.V. All rights reserved.

Dopant fluctuations in silicon wafers are responsible for systematic errors in the determination of the particle crossing point in silicon drift detectors. In this paper, we report on the first large-scale measurement of this effect by means of a particle beam. A significant improvement of the anodic resolution has been obtained by correcting for these systematic deviations.

We present the measurements of primary protons and helium nuclei performed by the Wizard Collaboration in different balloon-borne campaigns. A superconducting magnet spectrometer was used in these experiments together with detectors for particle recognition. These combinations of detectors made it possible to perform accurate particle measurements over a large (up to 200 GV for protons) energy interval. We focus in particular on the results from the MASS91 and CAPRICE94 experiments: We find a very good agreement between these two sets of measurements, also in comparison to other recent results. All these results seem to suggest that the normalization of primary cosmic rays may be significantly lower than previously estimated.

We provide in this paper a status report of the space experiment PAMELA. PAMELA aims primarily to measure the flux of antiparticles, namely antiprotons and positrons, in cosmic rays with unpreceden ...

A Silicon Drift Detector (SDD) with an active area of 7:0 � 7: 5c m 2 has been designed, produced and tested for the ALICE Inner Tracking System. The development of the SDD has been focused on the capability of the detector to work without an external support to the integrated high-voltage divider. Several features have been implemented in the design in order to increase the robustness and the long-term electrical stability of the detector. One of the prototypes has been tested in a pion beam at the CERN SPS. Preliminary results on the position resolution are given. # 2001 Elsevier Science B.V. All rights reserved.

The DSI collaboration goal has been the development of large-area silicon drift detectors (SDD) adapted to large-scale production in industry. Such a development is necessary for the use of SDDs in large tracking systems, such as the one proposed for the ALICE experiment at LHC (see Ref. [1] ). One of the necessary steps towards large-scale production is the study of the doping uniformity in commercially available Si wafers. We have performed a series of measurements aimed at the evaluation of large-scale fluctuations of doping concentration and of the possible influence on the detector quality induced by processing steps. In this paper, we report final results of both resistivity fluctuations and leakage currents measurements.

We report new results for the cosmic-ray antiproton-to-proton ratio from 3 to 50 GeV at the top of the atmosphere. These results represent the first measurements, on an event-by-event basis, of mass-resolved antiprotons above 18 GeV. The results were obtained with the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas-RICH (Ring-Imaging Cerenkov) counter and a silicon-tungsten imaging calorimeter. The RICH detector was the first ever flown that is capable of identifying charge-one particles at energies above 5 GeV. The spectrometer was flown on 1998 May 28‐29 from Fort Sumner, New Mexico. The measured /p ¯ p ratio is in agreement with a pure secondary interstellar production. Subject headings: acceleration of particles — balloons — cosmic rays — dark matter — elementary particles

A very large-area (6.75×8 cm2) silicon drift detector with integrated high-voltage divider has been designed, produced and fully characterised in the laboratory by means of ad hoc designed MOS injection electrodes. The detector is of the “butterfly” type, the sensitive area being subdivided into two regions with a maximum drift length of 3.3 cm. The device was also tested in a pion beam (at the CERN PS) tagged by means of a microstrip detector telescope. Bipolar VLSI front-end cells featuring a noise of 250 e− rms at 0 pF with a slope of 40 e−/pF have been used to read out the signals. The detector showed an excellent stability and featured the expected characteristics. Some preliminary results will be presented.

Only a few charge preamplifiers suitable for use with Large Area Silicon Detectors have been realised as integrated circuits. In this paper we presents some of them that includes in the same chip both a charge preamplifier and a shaper, dramatically cutting power dissipation, size and cost. The resolution achieved is very good. It is intended in particular for use in Intermediate Energy Physics Experiments.

Silicon Drift Detectors (SDDs) are well suited to high-energy physics experiments with relatively low event rates. In particular SDDs will be used for the two intermediate layers of the Inner Tracking System of the ALICE experiment. Beam test results of linear SDD prototypes have shown a resolution of 40×30 μm2 and a cluster finding efficiency of essentially 100% with E=600 V/cm.

We report results of drift velocity monitoring in silicon drift detectors, obtained in beam test conditions using MOS charge injectors. We are able to correct velocity variations as small as 0.1% due to temperature variations of the order of 0.1 K and consequently maintain an optimal space resolution.

A linear array silicon pixel detector has been developed to perform digital radiology with synchrotron radiation: in this communication we present the first results obtained using a three layer prototype at the Elettra Synchrotron Radiation Facility (Trieste, Italy). High efficiency (about 85% at 20 keV) is achieved by means of an Si strip detector irradiated in an 'edge-on' geometry: the pixel dimensions are 200 X 300 micrometer2. To obtain a sensitive area of about 50 X 1 mm2 stack of three layers has been assembled. Images are obtained by means of scanning techniques and their spatial resolution is determined by the scanning step. Detectors are read-out by dedicated, low noise VLSI CMOS chips in single photon counting mode. The distance between each detector layer has been measured to be 115 plus or minus 10 micrometer and the layers are parallel within a maximum tilt angle of 0.08 degrees. Cross-talk effects were found to be always smaller than 2% of the counts of the neighboring layers. The MTF in the scan direction has been evaluated. The acquisition time needed to acquire an image of a mammographic test object is about 6 minutes. The mean glandular dose is about 30% of the dose delivered at the conventional mammographic unit for the same test object while the detail visibility is comparable. These preliminary results indicate that a large area linear array silicon pixel detector can be developed: using this detector and a monochromatic synchrotron radiation beam the delivered mean glandular dose is significantly reduced when compared to conventional mammographic examinations.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

One major goal of modern radiology is the improvement of image quality and subsequently the development of sophisticated radiographic methods which are capable of detecting low contrast and small size details in organic samples in particular in mammography where the requirements on contrast resolution and spatial resolution are extremely high. Significant improvements in image quality have been achieved by the SYRMEP (SYnchrotron Radiation for MEdical Physics) collaboration which has designed and built a beamline devoted to medical physics at the synchrotron radiation facility ELETTRA in Trieste (Italy). The detection system developed for digital mammography consists of a silicon pixel detector with a pixel size of 200 X 300 micrometers 2 used in the `edge on' configuration in order to achieve a high conversion efficiency. The detector is equipped with a low noise VLSI amplifier chain; at present. Recently, a multilayer detector prototype has been implemented, consisting of a stack of three single silicon strip layers. This set-up provides a larger sensitive area and subsequently a reduction of the exposure time. Digital images of mammographic phantoms and of in vitro full breast tissue samples show a higher contrast resolution and lower absorbed dose when compared to conventional mammographic images. Besides, further promising studies have been initiated developing novel imaging methods based on the phase effects evidenced by the high degree of coherence of the SR source. At the SYRMEP beamline several experiments have been carried out in order to exploit the potentials of two different techniques, Phase Contrast and Diffraction Enhanced Imaging, respectively. Images showing better detail visibility and enhanced contrast were produced with dose lower or comparable to the conventional one.

A novel linear silicon drift detector (SDD) is proposed in which the proper potential profile is established by the voltage drop along a unique p/sup +/ cathode implanted across the surfaces. This p/sup +/ implant, arranged in a zigzag shape, acts at the same time as voltage divider and field cathode and allows us to increase the sensitive area, improving also the uniformity of the thermal distribution and thus minimizing the fluctuation of the electron mobility on the sensitive zone of the SDD. The perturbations of the drift field due to the asymmetry of the strips constituting the zigzag cathode have been evaluated by solving analytically Poisson's equation for a simplified model of the structure. Three-dimensional numerical simulations have been carried out to prove the negligible amount of the perturbation and the effectiveness of the proposed structure. Based on this principle, a prototype has been manufactured at Canberra Semiconductor Company. Dynamic measurements of the time-of-flight of an injected charge prove that the linearity of the prototype and the drift uniformity in the anode direction are very high.

The Sirad experiment aims to measure with great precision the cosmic ray radiation environment on the outside of the International Space Station. The detector, composed of a stack of 32 silicon detectors arranged in X–Y pattern and surmounted by a scintillator system, is capable of detecting nuclei from protons to Iron in the energy range between ≃ 30 MeV / n and ≃ 5 GeV / n .

The peculiarity of the drift chamber prototype presented in this paper is the high voltage divider, which is implanted in the entire sensitive zone, thus, it has at the same time the function of drift electrode. This brings some advantage: (1) there is no metallization in the sensitive zone, hence, the detector can have a wider spectrum of applications (e.g. detection of soft X-rays and low-energy electrons); (2) the mask design and detector fabrications are made simpler; (3) a uniform power dissipation from the divider is assured. This detector is a “butterfly” bi-directional structure with a drift length of 16 mm for each half. Time-of-flight measurements in order to check the response uniformity of the suggested detector topography were performed by injecting charge with the use of a focused infrared laser. The rather good linearity and uniformity of the drift in different parts of the sensitive area are demonstrated.

The SYRMEP approach to digital mammography implies the use of a monochromatic X-ray beam from a synchrotron source and a slot of superimposed silicon microstrip detectors as a scanning image receptor. The microstrips are read by 32-channel chips mounted on 7-layer hybrid circuits which receive control signals and operating voltages from a MASTER-SLAVE configuration of cards. The MASTER card is driven by the CIRM, a dedicated CAMAC module whose timing function can be easily excluded to obtain data-storage-only units connected to different MASTERs: this second-level modular expansion capability fully achieves the tasks of an electronics system able to follow the SYRMEP detector growth till the final size of seven thousands of channels.

A silicon strip detector for the SYRMEP (SYncrotron Radiation for MEdical Physics) experiment has been designed and realised. The main features of this detector are AC-coupling through integrated coupling capacitors, DC biasing by means of a gated punch-through structure, bulk contact on the junction side through a forward-biased p/sup +/ implant and integrated fan-in on active silicon. Results of laboratory tests of the detector parameters, allowing a thorough evaluation of the technological solutions employed, are presented. The functionality of the detectors and the charge collection linearity have been tested with different /spl gamma/ sources, using a hybrid, low-noise front-end electronics.

We present a VLSI CMOS-mixed analog-digital circuit for high-rate pixel X-ray imaging applications. It consists of 32 channels at 80 μm pitch. The total die size is 3.7×14 mm 2 . Each channel features: a low-noise charge preamplifier, a CR-RC shaper, a buffer, a threshold discriminator and a 16-bit binary counter. The readout is done serially on a tri-state buffer. The main parameters of the analog part are: shaping time of 850 ns at 5 pF input capacitance, gain of 180 mV/fC, ENC( e − rms) = 60 + 17 C d (pF) and a power consumption of 3.8 mW/channel. The counting rate is limited by the analog part to around 100 kHz/channel for 1 fC charge pulses. Due to the parallelism of the circuit, photon rate in the order of 1 GHz/cm 2 can be measured for a pixel size of the order of 200 × 200 μ m 2 . The parameters of the circuit were optimised for the Syrmep experiment, an R&D project in digital mammography. The circuit was produced in 1.2 μm CMOS technology by AMS (Austria). Characterisation of the circuit, as well as first-imaging results of the circuit connected to microstrips or pixel detectors are presented. They show the circuit works according to specification and can be used for imaging applications.

We present images of a mammographic test object obtained using a linear array silicon pixel detector capable of single-photon counting. The detector pixel size was 200 x 300 microns2 and images were acquired by scanning the test object between the laminar detector and the x-ray source with a scanning step of 100 microns. A molybdenum anode tube was used with two different filtrations: 2 mm aluminium and 25 microns molybdenum. Conventional film-screen images were also obtained in order to compare spatial and contrast resolution. In our digital images it is possible to recognize low-contrast details having dimensions smaller than or equal to the dimensions of details visible by means of a clinical mammographic unit. The detection of microcalcifications smaller than 150 microns was possible only when using the Mo filtration. However a copper wire of 50 microns diameter was detectable when embedded in a simulated tissue. We discuss in detail the mean glandular doses (MGDs) delivered during the image acquisition. The MGDs necessary to obtain good-quality images are always smaller than at a conventional mammographic unit. Since MGDs depend on the x-ray spectrum, the dose reduction becomes larger when the applied spectrum is harder than in film-screen acquisition (Al filtration and 35 kVp).

The SYRMEP project (SYnchrotron Radiation for MEdical Physics) intends to improve mammography performances using two non-traditional means: synchrotron radiation and silicon detectors. A silicon crystal (the monochromator) allows to choose the optimal beam energy that leads to the maximum signal to noise ratio, while the detectors are arranged to form a matrix of pixels and coupled to low noise high-gain VLSI integrated circuits making the single photon counting technique possible. We present the data acquisition system implemented to read out the VLSI circuit with particular emphasis on two dedicated CAMAC modules that generate the control signals and store the chip digital output on memories that can be accessed via the CAMAC bus. It has been useful in testing the chip performances and can be considered a prototype of the final SYRMEP data acquisition system.

A silicon strip detector for the SYRMEP (SYnchrotron Radiation for MEdical Physics) experiment has been designed and realised. The main features of this detector are AC-coupling through integrated coupling capacitors, DC bias of the strips by means of a gated punch-through structure, bulk contact on the junction side through a forward-biased p + implant, thinned entrance window for the incoming radiation (in an “edge-on” geometry) and integrated fan-in on active silicon. Results of laboratory tests of the detector parameters, allowing a thorough evaluation of the technological solutions employed, are presented.

The SYRMEP collaboration (Synchrotron Radiation for Medical Physics) is developing a novel imaging device to be used with a laminar monochromatic synchrotron radiation X-ray beam for applications in digital mammography. Its main components are silicon microstrip detectors and a dedicated VLSI readout chip based on the single photon counting concept. The innovative geometry-several overlapped detectors with strips parallel to the beam direction-determines a matrix of pixels, each of them having an area of 200/spl times/300 /spl mu/m/sup 2/, which can detect up to 10/sup 6/ photons/(mm/sup 2/ s) with 90% efficiency at 25 keV. Front-end and readout electronics are expandable in a modular fashion and can be coupled to successive receptor versions with increasing number of channels, while a VME based DAQ system offers full testing facilities. In our view this system is providing specific and original contributions to digital mammography but it could also be useful in other modern radiology fields.

Having high spatial resolution and good energy response the silicon drift detector (SDD) finds specific applications in experimental physics. The aims of this project are: simplified detector production and operation, improved total-to-sensitivearea ratio and stable working conditions. We have started a systematic study which includes all elements of the device, the silicon wafer, the various electrodes, an improved technology and VLSI front-end electronics. Several prototypes have been produced and we are progressively testing them. We summarize here our program of work and present the results from the first drift structures tested.

The SYRMEP (SYnchrotron Radiation for MEdical Physics) collaboration is now developing a microstrip silicon detector with high granularity and high efficiency for research in digital mammography. The project is planning to use a monochromatic X-ray beam, from a bending magnet, of ELETTRA, the synchrotron facility installed in Trieste. The detector is a matrix of pixels, formed by the slacking of different layers of strip silicon pads, with pixel dimensions determined by the pitch and the thickness of the pads themselves. The final detector, an AC-coupled FOXFET-type high resistivity silicon pad, will cover the whole beam region of 4 x 150 mm(2). Different pixel sizes have been tested (from 0.5 x 0.5 mm(2) to 0.3 x 0.2 mm(2)). The dead volume in the front of the detector has been reduced in order to reach 80% efficiency in the photon collection. The stacking of the layers has been obtained by means of screen printing deposits of non-conductive glue whose height has been chosen in order to minimize the inter-layer dead region and the cross talk of superimposed pixels, We present here the results of our studies in terms of imaging and the status of the final detector.

The silicon strip microvertex detector of the DELPHI experiment at the CERN LEP collider has been recently upgraded from two coordinates (RΦ only) to three coordinates reconstruction (RΦ and z). The new Microvertex detector consists of 125 952 readout channels, and uses novel techniques to obtain the third coordinate. These include the use of AC coupled double sided silicon detectors with strips orthogonal to each other on opposite sides of the detector wafer. The routing of signals from the z strips to the end of the detector modules is done with a second metal layer on the detector surface, thus keeping the material in the sensitive area to a minimum. Pairs of wafers are daisy chained, with the wafers within each pair flipped with respect to each other in order to minimize the load capacitance on the readout amplifiers. The design of the detector and its various components are described. Results on the performance of the new detector are presented, with special emphasis on alignment, intrinsic precision and impact parameter resolution. The new detector has been taking data since spring of 1994, performing up to design specifications.

Scintillating glasses are a potentially cheaper alternative to crystal - based calorimetry with common problems related to light collection, detection and processing. As such, their use and development are part of more extensive R&D aimed at investigating the potential of total absorption, combined with the readout (DR) technique, for hadron calorimetry. A recent series of measurements, using cosmic and particle beams from the Fermilab test beam facility and scintillating glass with the characteristics required for application of the DR technique, serve to illustrate the problems addressed and the progress achieved by this R&D. Alternative solutions for light collection (conventional and silicon photomultipliers) and signal processing are compared, the separate contributions of scintillation and Cherenkov processes to the signal are evaluated and results are compared to simulation.

The DELPHI Microvertex detector, which has been in operation since the start of the 1990 LEP run, consists of three layers of silicon microstrip detectors at average radii of 6.3, 9.0 and 11.0 cm. The 73728 readout strips, oriented along the beam, have a total active area of 0.42 m2. The strip pitch is 25 μm and every other strip is read out by low power charge amplifiers, giving a signal to noise ratio of 15:1 for minimum ionizing particles. On-line zero suppression results in an average data size of 4 kbyte for Z0 events. After a mechanical survey and an alignment with tracks, the impact parameter uncertainty as determined from hadronic Z0 decays is well described by ( 69 p t ) 2 + 24 2 μm , with pt in GeV/c. For the 45 GeV/c tracks from Z0 → μ− decays we find an uncertainty of 21 μm for the impact parameter, which corresponds to a precision of 8 μm per point. The stability during the run is monitored using light spots and capacitive probes. An analysis of tracks through sector overlaps provides an additional check of the stability. The same analysis also results in a value of 6 μm for the intrinsic precision of the detector.

Light flashes are unusual visual phenomena that are observed in space and are caused by the interaction of energetic cosmic-ray particles with the human visual system. Using data gathered on board the Mir space station during the Sileye-2 experiment1, we show here that there are two separate components of cosmic rays that cause these flashes: one due to heavy nuclei and one due to protons. This indicates that perception by an astronaut's visual apparatus could involve two complementary mechanisms.

[1] The detector New Instrument for Nuclear Analysis (NINA) aboard the satellite Resurs-01-N4 detected hydrogen and helium isotopes geomagnetically trapped, while crossing the South Atlantic Anomaly. Deuterium and tritium at L shell < 1.2 were unambiguously recognized. The 3He and 4He power law spectra, reconstructed at L shell = 1.2 and B < 0.22 G, have indices equal to 2.30 ± 0.08 in the energy range 12–50 MeV nucleon−1 and 3.4 ± 0.2 in 10–30 MeV nucleon−1, respectively. The measured 3He/4He ratio and the reconstructed deuterium profile as a function of L shell bring one to the conclusion that the main source of radiation belt light isotopes at Resurs altitudes (∼800 km) and for energy greater than 10 MeV nucleon−1 is the interaction of trapped protons with residual atmospheric helium.

The concept of a new bidimensional photon-counting, MCPbased detector is presented together with estimates of imaging and dynamic range performances. The first results of tests on the position readout system, a silicon drift chamber, are also presented.

We report preliminary beam test results of linear Silicon Draft Detector prototypes for the ALICE experiment. Linearity, resolution, charge transport and collection, and efficiency have been studied using a minimum ionizing particle beam for a very large area detector prototype read out with the OLA preamplifier/shaper and for another detector read out using a new transimpedance amplifier with a non linear response.

A 3-layer edge-on silicon microstrip detector for the SYRMEP/FRONTRAD project has been designed and realised. The image matrix is made by 764 pixels with dimensions 300 (thickness of the single detectors) × 200 (strip pitch) μm2. The system has a sensitive area of 50 × 1 mm2, an inter-layer distance of ≈ 100 μm and an efficiency of ≈ 80% for 20 keV photons. The image is acquired by scanning the object across the beam cross-section and the overall statistics on the single pixel is obtained by summing up the information of corresponding pixels in the three layers, thereby reducing the effect of possible noisy or not functioning pixels. Experimental results obtained at the SYRMEP/FRONTRAD beam line of the ELETTRA synchrotron radiation machine with this innovative detector are presented.

The SYRMEP (SYnchrotron Radiation for MEdical Physics) imaging system is based on the combination of a monochromatic laminar X-ray beam, with a laminar high-efficiency pixel silicon detector. The use of synchrotron radiation X-rays has the advantage of minimising the radiation dose delivered to the sample because it is possible to choose the best energy for the considered radiological examination. The high efficiency of the detector (about 90% in 18-28 keV energy range) also lowers this dose figure. Since the detector is capable of single-photon counting, the information contained in the beam is fully exploited, leading to high contrast resolution. The present phase of the SYRMEP project involves a systematic study of in vitro breast tissue samples. The same samples are then imaged by means of a conventional mammographic Mo anode tube used in the common diagnostic practice and recorded on film/screen system. The comparison of the two imaging modalities shows the advantages, with special regard to contrast resolution, of the SYRMEP imaging system compared with conventional film-screen devices.

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, $15^{th}$ 2006 in a $350\times 600 km$ orbit with an inclination of 70 degrees. In this work we describe the scientific objectives and the performance of PAMELA in its first two years of operation. Data on protons of trapped, secondary and galactic nature - as well as measurements of the December $13^{th}$ 2006 Solar Particle Event - are also provided., Comment: To appear on J. Phys. Soc. Jpn. as part of the proceedings of the International Workshop on Advances in Cosmic Ray Science March, 17-19, 2008 Waseda University, Shinjuku, Tokyo, Japan

The PAMELA magnetic spectrometer, located on board the Resurs-DK1 satellite on Earth polar orbit with altitude of 350-600 km, measured the fluxes of cosmic ray particles and antiparticles in a wide energy range from ~ 50 MeV to several TeVs. In this paper new results on the "all-electron" (sum electrons and positrons) spectrum are presented. New improved analysis on the full data set from 2006 to 2016 allows a significant increase in statistic compared to previously published results and an extension of energy interval up to ~1 TeV

We describe the design of a Displacement Monitor System relying on local capacitance measurements. This system controls the relative position of the Delphi microstrip Vertex Detector at LEP. Results from the first months of data taking are presented. They show displacements are effectively monitored with the expected micron precision.

The cosmic-ray hydrogen and helium (1H,2H,3He,4He) isotopic composition between 100 MeV/n and 1.4 GeV/n has been measured with the satellite-borne experiment PAMELA, which was launched into low-Ear ...