Studies have been done and continue on the design and construction of a Shashlik detector using Radiation hard quartz capillaries filled with wavelength shifting liquid to collect the scintillation ...light from LYSO crystals for use as a calorimeter in the Phase II CMS upgrade at CERN. The work presented here focuses on the studies of the capillaries and liquids that would best suit the purpose of the detector. Comparisons are made of various liquids, concentrations, and capillary construction techniques will be discussed.
We are developing a calibration system for the Central Fiber Tracker (CFT) for the DO Upgrade to monitor the optical integrity, channel gain, and gain stability for the 76000 fiber channels with VLPC ...readout which comprise the system. Excitation is by blue Light Emitting Diodes (LEDs), with light distributed to the CFT fiber ribbons via luminous fiber panels. System design and performance will be presented.
Scintillating pad detectors Adams, D.; Baumbaugh, B.; Borcherding, F. ...
IEEE transactions on nuclear science,
06/1997, Letnik:
44, Številka:
3
Journal Article
Recenzirano
We have been investigating the performance of scintillating pad detectors, individual small tiles of scintillator that are read out with wavelength-shifting fibers and visible light photon counters, ...for application in high luminosity colliding beam experiments such as the DO Upgrade. Such structures could provide "pixel" type readout over large fiducial volumes for tracking, preshower detection and triggering.
Experimental applications requiring fast timing and/or high efficiency position and energy measurements typically use scintillation materials. Scintillators utilized for triggering, tracking, and ...calorimetry in colliding beam detectors are vulnerable to the high radiation fields associated with such experiments. We have begun an investigation of several fluorescent dyes which might lead to fast, efficient, and radiation resistant scintillators. Preliminary results of spectral analysis and efficiency are presented.
A calibration system for the testing of scintillating fibers and visible light photon counters (VLPC) has been constructed at Notre Dame and installed in a cosmic ray test facility at Fermilab. The ...purpose of the cosmic ray test is to assess the viability of the fiber tracking technique for the upgraded D0 central detector. The purpose of this calibration system is to monitor the performance of the 3072 fiber VLPC detector elements for continuity, gain and uniformity of response. Here we report on the design, construction and operation of the calibration system.< >
We have designed, constructed, and operated a small cryostem which supports the operation of 32 channels of Visible Light Photon Counters (HISTE-IV VLPCs). The VLPCs are situated within a small ...enclosure which can be lowered into a 36-100 liter dewar. The enthalpy of the boil-off helium keeps the VLPCs cold, and allows the system to be operated with stability for many days within the desired temperature range of 6-7.5 K. The cryostem is instrumented with clear fiber waveguides which transport the light from an optical connector situated at the top of the cryostem and outside of the dewar to the photosensors at cryogenic temperatures within the dewar. Electrical signals from the VLPCs are amplified at room temperature using QPA02 preamplifiers. Details of design and performance are reviewed.
Experimental applications requiring fast timing and/or high efficiency position and energy measurements typically use scintillation materials. Scintillators utilized for triggering, tracking, and ...calorimetry in colliding beam detectors are vulnerable to the high radiation fields associated with such experiments. We have begun an investigation of several fluorescent dyes which might lead to fast, efficient, and radiation resistant scintillators. Preliminary results of spectral analysis and efficiency are presented.
We have been studying ways in which the light from several optical fibers that transmit light from scintillating tiles can be mixed and combined a single Silicon Photo Multiplier (SiPM). The purpose ...for mixing is to prevent a single high intensity fiber from saturating an area of the SiPM and thus causing an inaccurate reading of the overall light collected. In particular this is for use in detectors such as CMS HCAL 1, 2 where light is transmitted from scintillating tiles in 940µm fibers to a single photo-detector. If one tile has a large optical signal it can saturate an area of the SiPM and produce a signal lower than would be expected, resulting in an in-accurate energy measurement. The results of the test and the test setup will be described.
Scintillating, waveshifting, and waveguide fibers are used as particle detectors and light detection and transport elements in particle physics experiments. A study of light emission from such ...structures is being carried out for the Compact Muon Solenoid (CMS) experiment at CERN. For CMS, the fibers used are polystyrene core with a double-cladding and a diameter of 940 microns and lengths of up to several meters. Currently, the light produced and transported by such structures is detected by a conventional photo-detectors called hybrid photodiodes (HPD). The experiment is planning to replace the HPDs with a new photo-detectors known as a Silicon Photomultipliers (SiPM) with the possibility of each fiber having its own SiPM element for readout. Due to the thermal and electrical characteristics of SiPMs, and specifically their high thermal noise rate, it is best to keep the cross sectional area of the SiPM as small as possible. When light exits a fiber there is a distribution of the photons at various angles caused by: the differences in index of refraction of the core (n=1.59) and outer cladding (n=1.43) of the fiber; how and where in the fiber the initial light was created and the dominant transmission characteristics of the fiber/waveguide. This light distribution sets the size and placement of the SiPM devices. To study this, experimental measurements are being carried out using waveshifting and clear optical waveguide fibers that are used in CMS. Light is produced within such fiber core by exciting them through their cladding using UV light emitting diodes (LEDs). The LED light penetrates into the fiber and is waveshifted. On one end (called the readout end) is placed up against a fiber-optically-coupled CCD camera. The opposite end is either mirrored (with aluminum) or unmirrored and also read out using another CCD. Initial studies of attenuation and the profile of emergent light are discussed.
We report on results of a cosmic ray test of a scintillating fiber tracker using Visible Light Photon Counter (VLPC) readout. Two different detector configurations have been constructed and operated, ...the first with a total of 3072 channels and the second with 1,785 channels. The 3072 channel system is a prototype for the DO detector tracking upgrade and represents a configuration that is similar to that in the final detector. The second, smaller test was specifically designed to study the position resolution capabilities of the fiber tracker. A description of the cosmic ray test including trigger, fiber configuration, undoped lightguides, VLPC cassettes and cryogenics, and calibration system is given. Final results from the 3072 channel test will be presented, including measurements of resolution, light yield per minimum ionizing particle, singlet and doublet efficiency, and long-term stability. Resolution results from the second, 1785 channel test will be compared to the predicted resolution from Monte Carlo studies.
