Dr
Matthew Szydagis
(UC Davis)
29/05/2013, 09:10
A comprehensive model for explaining the scintillation and electroluminescence yields, and pulse shapes, in liquid and gaseous noble elements will be presented which informs an exhaustive simulation code called NEST (Noble Element Simulation Technique). All available liquid xenon data on electron and nuclear recoils have been incorporated, and significant progress has been made on extending...
Dr
Ettore Segreto
(Laboratori Nazionali del Gran Sasso)
29/05/2013, 09:35
A simple model for the estimation of the light yield of a scintillation detector is developed under general assumptions and relying exclusively on the knowledge of its optical properties. The model allows to easily incorporate effects related to Rayleigh scattering and absorption of the photons. The predictions of the model are benchmarked with the outcomes of Monte Carlo simulations of...
Dr
Benton Pahlka
(Fermilab)
29/05/2013, 10:00
We have constructed a GEANT4-based detailed software model of photon transport in polystyrene-based clear and wavelength shifting fibers. We have validated the model using data from several experiments and test bench studies using LEDs. In the model, we account for all spectral properties of materials such as bulk absorption and (re)emission and refractive indices. In this talk, I will...
Thomas Caldwell
(University of Pennsylvania)
29/05/2013, 10:55
Hamamatsu's R5912-02 MOD is an 8 inch diameter cryogenic photomultiplier tube of interest for light detection in large liquid noble dark matter and neutrino detectors. The R5912-02 MOD will be used in the MiniCLEAN single phase liquid argon dark matter detector and has been tested and characterized at cryogenic temperatures in the single photoelectron regime. A detailed model of the single...
Dr
Alexey Lyashenko
(UCLA)
29/05/2013, 11:20
To satisfy the requirements of the next generation of dark matter detectors based on the dual phase TPC, Hamamatsu, has developed the R11410-21 photomultipler tube. We present the results of the detailed measurements of various PMT characteristics. High QE (>30%) accompanied by a low dark count rate (50 Hz at 0.3 PE) and high gain (10^7) with good single PE resolution have been observed. A...
Dr
Ettore Segreto
(INFN-LNGS), Dr
Nicola Canci
(UCLA & INFN-LNGS)
29/05/2013, 12:45
Silicon photosensors actually represent a viable alternative to standard photomultipliers in fields such as communications and medical imaging. We explored the interesting possibility of using these sensors in combination with liquid Argon (LAr) for astroparticle physics applications such as neutrino, dark matter and double beta decay experiments. In fact, silicon photosensors have detection...
21.
QUartz Photon Intensifying Detector (QUPID): a possible alternative for noble liquid experiments
Dr
Alexey Lyashenko
(UCLA)
29/05/2013, 13:10
Dark matter and double beta decay experiments require extremely low radioactivity within the detector materials. For this purpose, the University of California, Los Angeles and Hamamatsu Photonics
have developed the QUartz Photon Intensifying Detector (QUPID), an ultra-low background photodetector based on the Hybrid Avalanche Photo Diode (HAPD) and entirely made of ultraclean synthetic fused...
Dr
Andrey Elagin
(University of Chicago)
29/05/2013, 13:35
The development of large-area imaging photodetectors with sub-nanosecond time resolutions and millimeter-level spatial resolutions allows detailed track reconstruction based on the precise transit times and position of individual photons. The Large Area Picosecond Photodetector (LAPPD) collaboration has developed large area microchannel plate-based photodetectors with such high resolutions...
Mr
Benjamin Jones
(MIT)
29/05/2013, 14:15
In this talk I will discuss some recent results from the Bo test stand at the Proton Assembly Building, Fermilab. This test stand has been used to characterize elements of the MicroBooNE optical system as well as to perform studies of processes affecting argon scintillation light such as scintillation quenching and optical absorption by impurities.
Dr
Henning Back
(Princeton University)
29/05/2013, 14:40
The cosmogenic $^39$Ar concentration in atmospheric argon is 8.1x10$^{-16}$, which amounts to 1Bq of $^39$Ar decays in a kg of atmospheric argon. This decay rate can limit the size of liquid argon dark matter detectors due to pile-up. The cosmic ray shielding by the earth means that argon from deep underground should not contain $^39$Ar. CO$_2$ wells in Southwestern Colorado have been found to...
Dr
Benton Pahlka
(Fermilab)
29/05/2013, 15:05
The solid (crystalline) phase of xenon possesses many of the same advantages of liquid xenon as a particle detector material including good transparency and ionization drift, self-shielding, low intrinsic background, and high scintillation light yield. Many of the properties of solid xenon have been measured previously employing small volumes and thin films. However, few systematic studies...
Dr
Aaron Manalaysay
(University of Zurich)
30/05/2013, 09:25
Many dark-matter models have been invoked to attempt to explain the observed annual modulation in the event rate of the DAMA/LIBRA experiment. While most models focus on WIMP-like dark matter that produces nuclear recoil signals, axion-like particles have been proposed that could produce the observed ~2-5 keV peak in the data. Dark-matter searches using germanium have been able to exclude...
Dr
Ettore Segreto
(Laboratori Nazionali del Gran Sasso), Dr
Nicola Canci
(Laboratori Nazionali del Gran Sasso)
30/05/2013, 10:25
Tetra Phenyl Butadiene (TPB) is the most commonly used compound to wave-shift the
128 nm scintillation light of liquid Argon down to the visible spectrum. We present a study on the loss of conversion efficiency of thin TPB films evaporated on reflective foils when exposed to light and atmosphere. The efficiency of the films is measured and monitored with a dedicated set-up that uses gaseous...
Stuart Mufson
(Indiana U)
30/05/2013, 10:50
Current and future neutrino and dark matter experiments use waveshifters to detect the VUV scintillation photons from liquid noble elements. The efficiency of these waveshifters can be affected by exposure to optical and near UV light. We have compared the degradation of the absorption efficiency of bis-MSB (p-bis(o-methylstyryl)benzene) and TPB (1,1,4,4-tetraphenyl-1,3-butadiene) on...
Jennifer VanGemert
(Fermilab)
30/05/2013, 11:15
We report on studies of degradation mechanisms of tetraphenyl butadiene (TPB) coatings of the type used in neutrino and dark matter liquid argon experiments. Using gas chromatography coupled to mass spectrometry we have detected the ultraviolet-blocking impurity benzophenone. We monitored the drop in performance and increase of benzophenone concentration in TPB plates with exposure to...
Mr
Brian Baptista
(Indiana University)
30/05/2013, 11:40
Future neutrino and dark matter experiments require the detection of scintillation photons from detectors that use liquid noble elements as the active detector medium. These scintillation photons are generated in the VUV region (< 200 nm) of the spectrum.
We present here the results of comparative studies of the absorption spectra in the VUV of the waveshifters bis-MSB...
Prof.
Paul Huffman
(North Carolina State University)
30/05/2013, 13:05
In an experiment to measure the neutron beta-decay lifetime using magnetically trapped ultracold neutrons, neutron decays are detected using the scintillation process in liquid helium. When a neutron decays, the decay electron deposits on average 250 keV within the liquid. The helium then scintillates in the extreme ultraviolet, producing ~5500 EUV photons. The trap walls are coated with...
Flavio Cavanna
(Yale U.), Prof.
Roberto Francini
(Università degli Studi di Roma Tor Vergata)
30/05/2013, 13:30
The use of efficient wavelength-shifters from the vacuum-ultraviolet to the photosensor’s
range of sensitivity is a key feature in detectors for Dark Matter search and Neutrino
physics based on liquid argon scintillation detection. Thin film of Tetraphenyl-butadiene (TPB)
deposited onto the surface delimiting the active volume of the detector and/or onto the photosensor
optical window is...
Ryan Wasserman
(Colorado State University)
30/05/2013, 13:55
The proposed LBNE experiment will use liquid argon TPCs for the far detector. We are developing a prototype photon detector for potential use in the LBNE far detector. This prototype is based on wavelength shifting fibers and will utilize silicon photomultipliers for readout. In this talk I will describe progress and plans on the prototype development. I will also provide an update on the...
Dr
Victor Gehman
(Lawrence Berkeley National Laboratory)
30/05/2013, 14:20
In either liquid xenon or high-pressure xenon gas, scintillation occurs in a band centered at 175 nm, a region directly accessible to PMTs, without the need for an intermediate wavelength-shifting (WLS) step. However, this generally requires a reflective surface such as teflon and directly positioning the PMTs, with all their radioactive burden, to stare directly into the active volume of...
Dr
Victor Gehman
(Lawrence Berkeley National Laboratory)
30/05/2013, 14:45
Radiation detectors with noble gasses as the active medium are becoming increasingly common in experimental programs searching for physics beyond the standard model. Nearly all of these experiments rely to some degree on collecting scintillation light from noble gasses. The VUV wavelengths associated with noble gas scintillation mean that most of these experiments use a fluorescent material...