Multianode Photo Multipliers for Ring Imaging Cherenkov Detectors

The 64-channel Multianode Photo Multiplier has been evaluated as a possible choice for the photo detectors of the LHCb Ring Imaging Cherenkov detector.Comment: 3 pages, 3 figures, contributed to the Proceedings of ICHEP200

Status of the LHCb Experiment

We present the status of the LHCb experiment which will make precision measurements of CP violation in $B$ meson decays. The motivation for the experiment and an overview of the detector design are given. The vertex detector, ring imaging Cherenkov counter, calorimeters, and trigger systems are discussed in detail. We also present the expected physics performance for selected modes.Comment: 10 pages, 16 figures, presented at BEAUTY2000, Israe

Performance measurements of Total Body PET scanner simulations using the Geant4 toolkit

Total-Body PET (TB PET) is a novel imaging modality that can image the whole body in a single scan. It has increased sensitivity, improved spatial resolution, reduced imaging times compared to conventional clinical PET scanners, and has the potential to detect smaller lesions and multiorgan diseases. Commercially available TB PET scanners include the Siemens Biograph Vision Quadra [1] and the United Imaging uEXPLORER [2].                                                                                                                                     This study uses the Geant4 toolkit [3] to create a simulation model of two different TB PET detector geometries; Siemens Biograph Vision Quadra and uEXPLORER. Analysis of simulated data and performance measurements were carried out in Python. The study follows the NEMA NU-2 2018 standard [4]. The simulation was used to explore the effect of different scintillator crystals and evaluates the count rate performance and the sensitivity of the scanner. The simulated data was compared to published experimental data from Siemens and Explorer. Good agreement between the count rates of simulated and experimental data was observed for both geometries. The simulated Siemens Quadra measured a system sensitivity value of 178.6 cps/kBq showing a 2% difference compared to the experimental data of 175.3 cps/kBq for LSO crystals. Axial sensitivity profiles plotted also match well. The comparison of different scintillators showed that BGO performs best as it has the highest peak NECR, thus good signal-to-noise ratio. LSO and LYSO also perform well and their physical properties are similar. NaI and CsI exhibit the worst performance; with low true count rates and the random count rates increased almost linearly with activity concentration. Our simulations compared well against experimental data, allowing us to test further scintillator materials and radioisotopes. After implementing image reconstruction and relevant corrections, this simulation can be used for validation of various research ideas in the future. Please click on the \u27PDF\u27 for the full abstract

Determination of 2beta_s in B_s -> J/psi K^+ K^- Decays in the Presence of a K^+K^- S-Wave Contribution

We present the complete differential decay rates for the process B_s -> J/psi K^+ K^- including S-wave and P-wave angular momentum states for the K^+ K^- meson pair. We examine the effect of an S-wave component on the determination of the CP violating phase 2beta_s. Data from the B-factories indicate that an S-wave component of about 10% may be expected in the phi(1020) resonance region. We find that if this contribution is ignored in the analysis it could cause a bias in the measured value of 2beta_s towards zero of the order of 10%. When including the K^+K^- S-wave component we observe an increase in the statistical error on 2beta_s by less than 15%. We also point out the possibility of measuring the sign of cos2beta_s by using the interference between the K^+K^- S-wave and P-wave amplitudes to resolve the strong phase ambiguity. We conclude that the S-wave component can be properly taken into account in the analysis.Comment: 11 pages, 6 figure