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.
120972438
Liquid xenon as a dark matter detector. Prospects for nuclear recoil discrimination by photon timing
Abstract Two mechanisms lead to liquid xenon scintillatlon, and are excited differently by incident electrons and by heavy charged nuclei. This could be used to discriminate nuclear recoil events from radioactive background in a search for hypothetical Galactic dark matter particles. To achieve low energy threshold a likelihood analysis is proposed using the time intervals between detected photons. Results are presented of Monte Carlo simulations, showing the background rejection achievable as a function of the number of detected photons. Some comments are included on background discrimination by simultaneous measurement of scintillation and ionization signals.
120318511
Measurement of Nuclear Recoil Response of Dark Matter Scintillating Targets Using Neutron Scattering
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.
119930862
A study of the monitoring of radiation damage to CMS ECAL crystals, performed at X5-GIF
The ratio R, defined as the fractional decrease in the beam signal divided by the fractional decrease in the light monitoring signal, was measured at the GIF-X5 facility for a set of 20 ECAL barrel crystals. The dependence of R on the wavelength of the injected monitoring light and its path length in the crystals was studied. Measurements of the inter-crystal variation in R are presented for 10 pre-production crystals. Results on the dependence of signal loss on the irradiation profile are given. The use of lead filters, placed between a 137Cs source and a crystal, to reproduce different longitudinal irradiation profiles has been tested.
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.
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.
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.
126252051
Understanding and calibrating the DS-ECal for T2K's ND280