PMT Test Facility at MPIK Heidelberg and Double Chooz Super Vertical Slice

Proceedings supplement for conference poster at Neutrino 2010, Athens, Greece

Transit Time and Charge Correlations of Single Photoelectron Events in R7081 PMTs

During the calibration phase of the photomultiplier tubes (PMT) for the Double Chooz experiment the PMT response to light with single photoelectron (SPE) intensity was analysed. With our setup we were able to measure the combined transit time and charge response of the PMT and therefore we could deconstruct and analyse all physical effects having an influence on the PMT signal. Based on this analysis charge and time correlated probability density functions were developed to include the PMT response in a Monte Carlo simulation.Comment: minor changes by referee reques

Transit Time and Charge Correlations of Single Photoelectron Events in R7081 PMTs

During the calibration phase of the photomultiplier tubes (PMT) for the Double Chooz experiment the PMT response to light with single photoelectron (SPE) intensity was analysed. With our setup we were able to measure the combined transit time and charge response of the PMT and therefore we could deconstruct and analyse all physical effects having an influence on the PMT signal. Based on this analysis charge and time correlated probability density functions were developed to include the PMT response in a Monte Carlo simulation.Comment: minor changes by referee reques

Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

Qualification Tests of the R11410-21 Photomultiplier Tubes for the XENON1T Detector

The Hamamatsu R11410-21 photomultiplier tube is the photodetector of choice for the XENON1T dual-phase time projection chamber. The device has been optimized for a very low intrinsic radioactivity, a high quantum efficiency and a high sensitivity to single photon detection. A total of 248 tubes are currently operated in XENON1T, selected out of 321 tested units. In this article the procedures implemented to evaluate the large number of tubes prior to their installation in XENON1T are described. The parameter distributions for all tested tubes are shown, with an emphasis on those selected for XENON1T, of which the impact on the detector performance is discussed. All photomultipliers have been tested in a nitrogen atmosphere at cryogenic temperatures, with a subset of the tubes being tested in gaseous and liquid xenon, simulating their operating conditions in the dark matter detector. The performance and evaluation of the tubes in the different environments is reported and the criteria for rejection of PMTs are outlined and quantified.Comment: 24 pages, 16 figure

Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

The BNO-LNGS joint measurement of the solar neutrino capture rate in 71Ga

We describe a cooperative measurement of the capture rate of solar neutrinos by the reaction 71Ga(\nu_e,e^-)71Ge. Extractions were made from a portion of the gallium target in the Russian-American Gallium Experiment SAGE and the extraction samples were transported to the Gran Sasso laboratory for synthesis and counting at the Gallium Neutrino Observatory GNO. Six extractions of this type were made and the resultant solar neutrino capture rate was 64 ^{+24}_{-22} SNU, which agrees well with the overall result of the gallium experiments. The major purpose of this experiment was to make it possible for SAGE to continue their regular schedule of monthly solar neutrino extractions without interruption while a separate experiment was underway to measure the response of 71Ga to neutrinos from an 37Ar source. As side benefits, this experiment proved the feasibility of long-distance sample transport in ultralow background radiochemical experiments and familiarized each group with the methods and techniques of the other.Comment: 7 pages, no figures; minor additions in version

Searching for sterile neutrinos in ice

Oscillation interpretation of the results from the LSND, MiniBooNE and some other experiments requires existence of sterile neutrino with mass $\sim 1$ eV and mixing with the active neutrinos $|U_{\mu 0}|^2 \sim (0.02 - 0.04)$. It has been realized some time ago that existence of such a neutrino affects significantly the fluxes of atmospheric neutrinos in the TeV range which can be tested by the IceCube Neutrino Observatory. In view of the first IceCube data release we have revisited the oscillations of high energy atmospheric neutrinos in the presence of one sterile neutrino. Properties of the oscillation probabilities are studied in details for various mixing schemes both analytically and numerically. The energy spectra and angular distributions of the $\nu_\mu-$events have been computed for the simplest $\nu_s-$mass, and $\nu_s - \nu_\mu$ mixing schemes and confronted with the IceCube data. An illustrative statistical analysis of the present data shows that in the $\nu_s-$mass mixing case the sterile neutrinos with parameters required by LSND/MiniBooNE can be excluded at about $3\sigma$ level. The $\nu_s- \nu_\mu$ mixing scheme, however, can not be ruled out with currently available IceCube data.Comment: 41 pages, 16 figures. Accepted for publication in JHEP. Minor changes from the previous versio

Comment on "On the subtleties of searching for dark matter with liquid xenon detectors"

In a recent manuscript (arXiv:1208.5046) Peter Sorensen claims that XENON100's upper limits on spin-independent WIMP-nucleon cross sections for WIMP masses below 10 GeV "may be understated by one order of magnitude or more". Having performed a similar, though more detailed analysis prior to the submission of our new result (arXiv:1207.5988), we do not confirm these findings. We point out the rationale for not considering the described effect in our final analysis and list several potential problems with his study.Comment: 3 pages, no figure