Summary of the 2007 CALICE test beam at CERN

This document summarizes the test beam programme that has been carried out by the CALICE Collaboration in the H6B test area at CERN between June and August 2007

Neutron irradiation effect on SiPMs up to Φneq\Phi_{neq} = 5 ×\times 1014^{14} cm−2^{-2}

Silicon Photo-Multipliers (SiPM) are becoming the photo-detector of choice for increasingly more particle detection applications, from fundamental physics to medical and societal applications. One major consideration for their use at high-luminosity colliders is the radiation damage induced by hadrons, which leads to a dramatic increase of the dark count rate. KETEK SiPMs have been exposed to various fluences of reactor neutrons up to $\Phi_{neq}$ = 5$\times$10$^{14}$ cm$^{-2}$ (1 MeV equivalent neutrons). Results from the I-V, and C-V measurements for temperatures between $-$30$^\circ$C and $+$30$^\circ$C are presented. We propose a new method to quantify the effect of radiation damage on the SiPM performance. Using the measured dark current the single pixel occupation probability as a function of temperature and excess voltage is determined. From the pixel occupation probability the operating conditions for given requirements can be optimized. The method is qualitatively verified using current measurements with the SiPM illuminated by blue LED light

Perioperative use of prothrombin complex concentrates

Prothrombin complex concentrates (PCCs) are purified drug products with hemostatic activity derived from a plasma pool. Today, PCCs contain a given and proportional amount of four non-activated vitamin K-dependent coagulation factors (II, VII, IX, and X), a variable amount of anticoagulant proteins (proteins C and S, and in some antithrombin) and low-dose heparin. In some countries PCC products contained only three clotting factors, II, IX, and X. Dosage recommendations are based on IU of F-IX, so that one IU of F-IX represents the activity of F-IX in 1 mL of plasma. Reversion of the anticoagulant effect of vitamin K antagonists (VKAs) in cases of symptomatic overdose, active bleeding episodes, or need for emergency surgery is the most important indication for PCCs and this effect of PCCs appears to be more complete and rapid than that caused by administration of fresh frozen plasma. They may be considered as safe preparations if they are used for their approved indications at the recommended dosage with adequate precautions for administration, and have been shown to be effective for reversing the effect of VKAs. Their adequate use based on decision algorithms in the perioperative setting allows a rapid normalization of International Normalized Ratio (INR) for performing emergency surgery, minimizing bleeding risk. This review aims to propose two algorithms for the use of PCCs in the perioperative setting, one to calculate the PCCs dose to be administered in a bleeding patient and/or immediately before urgent surgery, based on patient's clinical status, prior INR and INR target and another for reversing the action of oral anticoagulants depending on urgency of surgery

Application of the Micro Pixel Photon Counter to calorimetry and PET

Technological solutions are being investigated, in both fields of calorimetry and positron emission tomography, to increase the granularity of the detectors and achieve a better imaging resolution. The Geiger-mode avalanche photodiode looks a promising photo-detector for these compact designs. Up to now, the main limit of its application was the detection of the scintillation light, mostly ranging in the blue region: the traditional Geiger-mode avalanche photodiode is green sensitive. Hamamatsu has recently released a photo-detector of the same family, the Micro Pixel Photon Counter (MPPC), with a high photo-detection efficiency in the 420nm spectral region, opening a new scenario for the scintillator-based systems. The direct readout performances of a MPPC directly coupled to a plastic organic scintillator and to an inorganic scintillator (LSO) are systematically studied. Possible applications in highly granular calorimeters and positron emission tomography detectors are discussed

Hadron attenuation in deep inelastic lepton-nucleus scattering

We present a detailed theoretical investigation of hadron attenuation in deep inelastic scattering (DIS) off complex nuclei in the kinematic regime of the HERMES experiment. The analysis is carried out in the framework of a probabilistic coupled-channel transport model based on the Boltzmann-Uehling-Uhlenbeck (BUU) equation, which allows for a treatment of the final-state interactions (FSI) beyond simple absorption mechanisms. Furthermore, our event-by-event simulations account for the kinematic cuts of the experiments as well as the geometrical acceptance of the detectors. We calculate the multiplicity ratios of charged hadrons for various nuclear targets relative to deuterium as a function of the photon energy nu, the hadron energy fraction z_h=E_h/nu and the transverse momentum p_T. We also confront our model results on double-hadron attenuation with recent experimental data. Separately, we compare the attenuation of identified hadrons (pi^\pm, \pi^0, K^\pm, p and pbar) on Ne and Kr targets with the data from the HERMES Collaboration and make predictions for a Xe target. At the end we turn towards hadron attenuation on Cu nuclei at EMC energies. Our studies demonstrate that (pre-)hadronic final-state interactions play a dominant role in the kinematic regime of the HERMES experiment while our present approach overestimates the attenuation at EMC energies.Comment: 61 pages, 19 figures, version accepted for publication in Phys. Rev.