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An angular analysis of the decay B 0 → φK * (892) 0 is reported based on a pp collision data sample, corresponding to an integrated luminosity of 1.0 fb −1 , collected at a centre-of-mass energy of √ s = 7 TeV with the LHCb detector. The P-wave amplitudes and phases are measured with a greater precision than by previous experiments, and confirm about equal amounts of longitudinal and transverse polarization. The S-wave K + π − and K + K − contributions are taken into account and found to be significant. A comparison of the B 0 → φK * (892) 0 and B 0 → φK * (892) 0 results shows no evidence for direct CP violation in the rate asymmetry, in the triple-product asymmetries or in the polarization amplitudes and phases.

Measurement of the mass of the Λ

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The LHCb experiment is preparing for a major upgrade in 2018-2019. One of the key components in the upgrade is a new silicon tracker situated upstream of the analysis magnet of the experiment. The Upstream Tracker (UT) will consist of four planes of silicon strip detectors, with each plane covering an area of about 2 m 2 . An important consideration of these detectors is their performance after they have been exposed to a large radiation dose. In this article we present test beam results of pre-prototype n-in-p and p-in-n sensors that have been irradiated with fluences up to 4.0 × 10 14 n eq /cm 2 . Published in Nucl. Instrum. Meth. A. c CERN on behalf of the LHCb collaboration, licence CC-BY-4.0. arXiv:1506.00229v4 [physics.ins-det] 5 Nov 2015 ii

Neutron spallation sources always require new instrument upgrades and innovations in order to improve the quality of their experiments. In this framework, the capability to accurately measure total neutron cross sections at the VESUVIO instrument at the ISIS Facility can be boosted by a tailored transmission detector. For this reason, the first double ceramic thick GEM detector has been realised. Detectors based on GEM technology are broadly developed thanks to their characteristics, such as good spatial resolution (< 0.5 mm), good detection efficiency, high rate capability (MHz/mm2) and a possible coverage area of some meters at low costs. This article shows the realisation of a GEM detector made of a 10B4C cathode, two ceramic thick GEM foils and a padded anode, as well as the device characterisation on the VESUVIO beam line, where stability, γ-sensitivity, imaging capability and sample analysis have been studied. The successful results confirm that the ceramic thick GEM detector performs well in thermal and epithermal neutron detection and it will allow the scientific user community of the instrument to perform better quality transmission measurements so as to determine more accurate total neutron cross section of condensed-matter systems.

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Aim of the HICAM project is to build a new, compact Gamma-ray imager with a submillimeter spatial resolution, based on the Anger Camera principle. The system is composed of a detection module with frontend ASICs, an acquisition board and a host PC, where real-time data processing and image reconstruction is implemented. The detector is based on an array of 100 Silicon Drift Detectors (SDDs) of 1 cm 2 each in a 10 × 10 cm 2 format, coupled to a single scintillator crystal. Position of the interaction with the crystal and energy of the incident radiation are obtained through the use of a MLE algorithm, that optimally exploits the information obtained from the detectors. Moreover it is possible to modify the algorithm in order to determine the depth of interaction of the Gamma photon inside the crystal. The MLE algorithm, on the other hand, requires a large amount of calculations per event. In order to process the events in real-time we have implemented the MLE algorithm on a GPGPU, obtaining a processing rate of 150000 events/second, considering a FOV of 512 × 512 × 10 points (calculation of the z coordinate is performed). In the paper we discuss the derivation of the algorithm, its performance for what concerns spatial resolution and distortion, and the speed of its implementation on the GPGPU.