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    Commissioning of the CMS Hadron Forward Calorimeters Phase I Upgrade
    (Iop Publishing Ltd, 2018) Bilki, B.; Onel, Y.
    The final phase of the CMS Hadron Forward Calorimeters Phase I Upgrade was performed during the Extended Year End Technical Stop of 2016-2017. In the framework of the upgrade, the PMT boxes were reworked to implement two channel readout in order to exploit the benefits of the multi-anode PMTs in background tagging and signal recovery. The front-end electronics were also upgraded to QIE10-based electronics which implement larger dynamic range and a 6-bit TDC. Following this major upgrade, the Hadron Forward Calorimeters were commissioned for operation readiness in 2017. Here we describe the details and the components of the upgrade, and discuss the operational experience and results obtained during the upgrade and commissioning.
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    Development of Radiation-Hard Scintillators and Wavelength-Shifting Fibers
    (IEEE, 2018) Bilki, B.; Onel, Y.; Tiras, E.; Wetzel, J.; Winn, D.
    Future collider detectors impose unprecedented challenges on the radiation hardness of their detector components. We have performed R&D to develop radiation-hard active media for such detectors, calorimeters in particular. Among the options we have studied, quartz plates with thin radiation-hard coatings, intrinsically radiation-hard scintillators and radiation-hard wavelength-shifting fibers can be listed. Here we describe the recent advances in these developments and dicsuss recent and projected measurements.
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    Development of radiation-hard scintillators and wavelength-shifting fibers
    (Iop Publishing Ltd, 2018) Bilki, B.; Onel, Y.; Tiras, E.; Wetzel, J.; Winn, D.
    Future circular and linear colliders as well as the Large Hadron Collider in the High-Luminosity era have been imposing unprecedented challenges on the radiation hardness of particle detectors that will be used for specific purposes e.g. forward calorimeters, beam and luminosity monitors. We perform research on the radiation-hard active media for such detectors, particularly calorimeters, in two distinct categories: quartz plates coated with thin, radiation-hard organic or inorganic compounds, and intrinsically radiation-hard scintillators. In parallel to the effort on identifying radiation-hard scintillator materials, we also perform R&D on radiation-hard wavelength shifting fibers in order to facilitate a complete active medium for detectors under harsh radiation conditions. Here we describe the recent advances in the developments of radiation-hard scintillators and wavelength shifting fibers. We will discuss recent and projected measurements and future directions in development of radiation-hard active media.
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    Using LEDs to stimulate the recovery of radiation damage to plastic scintillators
    (Elsevier, 2017) Wetzel, J.; Tiras, E.; Bilki, B.; Onel, Y.; Winn, D.
    In this study, we consider using LEDs to stimulate the recovery of scintillators damaged from radiation in high radiation environments. We irradiated scintillating tiles of polyethylene naphthalate (PEN), Eljen brand EJ-260 (EJN), an overdoped EJ-260 (EJ2P), and a lab-produced elastomer scintillator (ES) composed of p-terphenyl (ptp) in epoxy. Two different high-dose irradiations took place, with PEN dosed to 100 kGy, and the others to 78 kGy. We found that the 'blue' scintillators (PEN and ES) recovered faster and maximally higher with LEDs than without. Conversely exposing the 'green' scintillators (EJ-260) to LED light had a nearly negligible effect on the recovery. We hypothesize that the 'green' scintillators require wavelengths that match their absorption and emission spectra for LED stimulated recovery. (C) 2017 Elsevier B.V. All rights reserved.