The LHCb experiment (The LHCb Technical Proposal, CERN/LHCC 98-4) is designed to study B meson physics in the LHC proton–proton collider at CERN. The Scintillator Pad Detector (SPD) has been designed ...to complete the calorimeter information performing an
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identification for the experiment level-0 trigger system. The detection technology consists in transmitting scintillation light by means of both Wavelength Shifting and clear fibers to fast multi-anode photomultiplier tubes. In this paper, it is described the instrumentation and setup used to characterize the baseline photomultiplier solution (Hamamatsu R5900-00-M64) together with the scintillators and optical fibers for the SPD at LHCb.
With the development of fast sampling electronics, digital pulse processing techniques for PET signals are raising interest. The optimal filter (OF) algorithm reconstructs pulse amplitude and time by ...two weighted sums, making it compatible with real-time implementation. The filters are usually optimized for stationary noise. We developed and tested a method to optimize the filters for the nonstationary noise of scintillation pulses. It is based on offline statistical analysis of coincident waveforms that could be applied during the system initialization phase. Experimental tests were done on a coincidence setup with two detection blocks composed of a fast inorganic scintillator ( LaBr 3 or LYSO) coupled to a photodetector (APD or PMT), preamplifiers and prefilters. The signals were sampled at high rate (250 MHz for APDs, 5 GHz for PMTs) and treated offline. The optimization of the filter coefficients for nonstationary noise yielded a significant improvement compared to those optimized for stationary noise, resp. 368 ps and 632 ps fwhm in coincidence for the LYSO-PMT setup. However, little improvement was achieved compared to leading-edge (DLED) and constant fraction (DCFD) discriminator algorithms (resp. 419 ps, 435 ps fwhm). Indeed, the adjustment of thresholds can be interpreted as an optimization for nonstationary noise. Yet, OF is more robust to white noise than DLED or DCFD. The applicability to PET is discussed.
The Lhcb experiment will study the CP symmetry violation in the system of the beauty particles. The detector is a 20-m-long spectrometer, to be installed on the proton–proton collider Lhc. Of major ...importance for the level 0 trigger is the preshower of the electromagnetic calorimeter designed to discriminate between electrons, hadrons and photons. The preshower cells consist of a two-radiation-length lead sheet located between two plastic scintillator planes. The scintillation light is extracted with wavelength-shifting fibres. The best candidates to read out the light of the 6000 detector cells are multianode photomultipliers. The HAMAMATSU photomultiplier R5900-00-M64 has been studied and its responses in terms of gain, linearity, uniformity within and between the anodes and cross-talk between the channels are addressed in this document.
Mass characterization of MaPMT tubes for the LHCb scintillator pad detector Graugés, Eugeni; Comerma, Albert; Garrido, Lluís ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2007, Letnik:
572, Številka:
1
Journal Article
Recenzirano
The final choice as the photomultiplier solution for both the LHCb Pre-Shower (PS) and the Scintillator Pad Detector (SPD) are the R7600-00-M64MOD Hamamatsu 64 channel photomultiplier tubes (MaPMT). ...A total of 220 units have been purchased to the manufacturer and around 100 units, the part corresponding to the SPD, have been characterized at the photon detection test bench facility in the University of Barcelona (UB) high energy physics group laboratory. There, the crucial features of the tubes such as linearity, gain, channel cross-talk and anode uniformity of response have been measured to ensure the compliance with the specifications agreed with the manufacturer.
We tested a digital front-end concept in order to evaluate the time resolution of PET detectors based on APD or PMT with digital read-out. Measurements were done on a coincidence set-up with two ...detection blocks composed of a fast inorganic scintillator (LaBr 3 or LYSO) coupled to a photodetector (APD or PMT), preamplificators and prefilters. The signals were sampled at high rate (250MHz for APDs, 5GHz for PMTs) and treated offline. Two different timing algorithms were applied: a digital method deriving from constant fraction discriminator, and an optimal filtering technique based on parameter estimation with minimal variance. The classical optimal filter was adapted to the non-stationary noise conditions, with a significant improvement of timing resolution. We describe these algorithms and discuss their performances.
This article reports the laser calibration of the hadronic Tile Calorimeter of the ATLAS experiment in the LHC Run 2 data campaign. The upgraded Laser II calibration system is described. The system ...was commissioned during the first LHC Long Shutdown, exhibiting a stability better than 0.8% for the laser light monitoring. The methods employed to derive the detector calibration factors with data from the laser calibration runs are also detailed. These allowed to correct for the response fluctuations of the 9852 photomultiplier tubes of the Tile Calorimeter with a total uncertainty of 0.5% plus a luminosity-dependent sub-dominant term. Finally, we report the regular monitoring and performance studies using laser events in both standalone runs and during proton collisions. These studies include channel timing and quality inspection, and photomultiplier linearity and response dependence on anode current.
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