14010060
Initial Tests on First Full-size ECAL Endcap Crystals
At the end of last year the first full size ECAL endcap crystals were delivered to CERN.Thirty in number, they were produced to the final geometrical specifications; 220mm long with a rear square face of 30mm and a front square face of 28.6mm. All were delivered polished. The visual inspection , dimension, transmission, light yield and light yield uniformity tests carried out since are discussed , with particular emphasis on the light yield uniformity. The results are very encouraging. suggesting that the endcap crystals will not need uniformisation.
94093096
UV quantum efficiencies of organic fluors
The need for, and benefits of using, wavelength shifters with certain dark matter scintillator detectors is discussed. The dependence of conversion efficiency on thickness and incident wavelength is extensively investigated for evaporated coatings of p-terphenyl and tetraphenyl butadiene, and for plastic waveshifters based upon p-terphenyl. For the latter the effect of varying the p-terphenyl concentration is studied and some factors which must be considered when developing them for use in the UV are also discussed.
121404010
The performance of prototype vacuum phototriodes in the first full sized supercrystal array for the CMS ECAL endcaps
The performance of prototype vacuum phototriodes is presented from the first full sized supercrystal array for the CMS ECAL endcaps. The array was exposed to high-energy electrons and tested in magnetic fields of up to 3 T, in the CERN North area, in July and August 1999. The mean VPT electron yield, normalised to a naked crystal light yield of 8 photoelectrons/MeV into an HPMT, was found to be 25 electrons/MeV at 3 T for devices from Research Institute Electron, 35 electrons/MeV for devices from Hamamatsu and 18/23 electrons/MeV from Electron Tubes.
118131577
Status Report and Recent Results from the UK Dark Matter Collaboration
The UK Dark Matter Collaboration (UKDMC) has an ongoing programme of detector development and operation with the eventual aim of reaching dark matter rates below 0.1/day/kg. Limits for the interaction rate have been set by this group and others using pulse shape discrimination in sodium iodide scintillation detectors. Methods for improving these limits through increased light output will be discussed, including avalanche photodiode R&D. To reach the lowest interaction rates we are collaborating with members of ICARUS on liquid xenon systems and this work is briefly reported.
17593732
Standard Model Higgs Search in the Four Jet Channel at LEP
The Standard Model Higgs boson was searched for at LEP, by the four collaborations in the year 2000, at centre-of-mass energies from 200-209GeV. An excess of events, potentially compatible with the production of a Higgs boson of mass ~115GeV was observed, largely in the four-jet channel. The search in this channel is discussed in this letter.
120752441
Observation of the UV scintillation light from high energy electron showers in liquid xenon
The UV scintillation light in liquid xenon has been observed using silicon drift photodiodes. Measurements were carried out in a rectangular light cell of dimentions 7.4 × 7.4 × 60 cm3 using 5 GeV electrons. The photodiodes and the preamplifiers were immersed in the liquid. A high quantum efficiency for 175 nm UV light has been measured. The scintillation light yield is found to be (1.5 ± 0.6) × 104 photons per MeV of energy deposited in liquid xenon. A light attenuation lenght of ≈ 40 cm has been measured.
121516515
The T2K experiment and downstream electromagnetic calorimeter
T2K (Tokai to Kamioka) is a 295km long-baseline experiment in Japan, which is due to start taking commissioning data late in 2009. It is designed to measure muon-neutrino oscillations to other flavours. This will enable the measurement of some of the components of the MNSP mixing matrix. One of the UK's main contributions is the construction of an Electromagnetic Calorimeter (ECal) for the near detector, ND280, situated 280m downstream from the neutrino production target. This poster focuses on the Downstream ECal. Construction of this key module is due to begin in October 2007. It is then to be packaged and shipped to CERN in Spring 2009 for calibration tests and it is the aim that it will be installed in Tokai later in 2009. Lancaster University is responsible for the construction of the DS-ECal.
17032836
Radiation Hardness of CCD Vertex Detectors for the ILC
Results of detailed simulations of the charge transfer inefficiency of a prototype CCD chip are reported. The effect of radiation damage in a particle detector operating at a future accelerator is studied by examining two electron trap levels, 0.17 eV and 0.44 eV below the bottom of the conduction band. Good agreement is found between simulations using the ISE-TCAD DESSIS program and an analytical model for the 0.17 eV level. Optimum operation is predicted to be at about 250 K where the effects of the traps is minimal which is approximately independent of readout frequency. This work has been carried out within the Linear Collider Flavour Identification (LCFI) collaboration in the context of the International Linear Collider (ILC) project.
25386498
Simulations of the Temperature Dependence of the Charge Transfer Inefficiency in a High-Speed CCD
Results of detailed simulations of the charge transfer inefficiency of a prototype serial readout CCD chip are reported. The effect of radiation damage on the chip operating in a particle detector at high frequency at a future accelerator is studied, specifically the creation of two electron trap levels, 0.17 eV and 0.44 eV below the bottom of the conduction band. Good agreement is found between simulations using the ISE-TCAD DESSIS program and an analytical model for the former level but not for the latter. Optimum operation is predicted to be at about 250 K where the effects of the traps is minimal; this being approximately independent of readout frequency in the range 7-50 MHz. This work has been carried out within the Linear Collider Flavour Identification (LCFI) collaboration in the context of the International Linear Collider (ILC) project.
115380373
NOvA: Present and Future
NOvA is a next generation neutrino oscillation experiment designed to search for muon neutrino to electron neutrino oscillations by comparing electron neutrino event rates in a Near Detector at Fermilab with the rates observed in a large Far Detector at Ash River, Minnesota, 810 km from Fermilab. The detectors are totally active, segmented, liquid scintillator detectors and are located 14 mrad off the NuMI beam axis. The Far Detector has begun construction and will begin taking data in early 2013. The experiment aims to measure the neutrino mixing angle theta_13 and will push the search for electron neutrino appearance beyond the current limits by more than an order of magnitude. For non-zero theta_13, it is possible for NOvA to observe CP violation in neutrinos and establish the neutrino mass hierarchy. The NOvA prototype near detector on the surface (NDOS) began running at Fermilab in November and registered its first neutrinos from the NuMI beam in December 2010. An overview and current status of the experiment will be presented.