Session H17: Instrumentation for Particle Physics

An Estimation of Photon Scattering Length in Tetraphenyl-butadiene

Tetraphenyl-butadiene (TPB) is a wavelength shifting material that can absorb ultraviolet photons and emit blue photons. It is used in the detection of vacuum ultraviolet (VUV) photons, for which typical photo-sensors, such as most photomultiplier tubes (PMT) and silicon photomultipliers (SiPM), do not have any quantum efficiency. The secondary blue light is emitted isotropically, however, due to scattering within the material, its angular distribution upon exiting the material can not be easily predicted. Here we describe a procedure for estimating the scattering length of blue light in TPB, by measuring and modeling the angular distribution as a function of layer thickness. The experiment consists of shining ultraviolet light at various thicknesses of TPB deposited on fused silica, and measuring the intensity of blue light using SiPMs on either side of the sample. We simulate light propagation within the sample to estimate the light yield and compare that to the data. This allows us to estimate mean scattering length for photons in TPB the results of which will be presented.   

Study the performance of LYSO and CeBr3 crystals using Silicon Photomultipliers

The Silicon Photomultipliers (SiPMs) are novel photon-detectors which have been progressively found their use in particle physics. Their small size, good single photon resolution, simple readout, and immunity to magnetic fields offers advantages compared to traditional photomultipliers. LYSO and CeBr3 crystals are relatively new scintillators with high light yield and fast decay time. The response of these detectors to low energy gamma rays and cosmic ray muons will be presented.   

Characterizing Scitillation and Cherenkov Light Yield in Water-Based Liquid Scintillators

The recent development of Water-based Liquid Scintillator (WbLS) has made it possible to produce scintillating materials with highly tunable light yields and excellent optical clarity. This allows for a straightforward combination of the directional properties of Cherenkov light with the greater energy resolution afforded by the typically brighter scintillation light, which lends itself well to a broad program of neutrino physics. Here we explore the light yields and optical properties of WbLS materials in development for Theia (formerly ASDC) as measured in our benchtop Theia R\&D at Berkeley Lab and extrapolate to larger detectors.   

Optimization of the SiD concept in the presence of ILC backgrounds

The International Linear Collider is a high-energy e+e- machine, planned to be built in Japan in the next decade. Its physics program features precision measurements of the top and Electroweak sectors and a discovery potential of Physics beyond the Standard Model complementary to that of the LHC. We present studies of machine-related background processes in the context of detector optimization. For each of the dominant background processes, we will present its main signature in the detector, impact on physics measurements, and strategies for mitigation in detector design and reconstruction algorithms. The studies are based on a detailed simulation of the SiD detector concept.   

A Compton Suppressed Gamma Ray Counter For Radio Assay of Materials

Rare event searches, such as direct dark matter experiments, require materials with ultra-low levels of natural radioactivity. We present a neutron activation analysis (NAA) technique for assaying metals, specifically titanium used for cryostat construction. Earlier attempts at NAA encountered limitations due to bulk activation via (n, p) reactions, which contributed to large continuum backgrounds due to Compton tails. Our method involves a heavy water shielded exposure to minimize (n,p) reactions and a sodium iodide shielded high purity germanium counter for the gamma ray assay. Preliminary results on assays for U/Th/K contamination in titaniumwill be presented.   

Recent Upgrades at the Fermilab Test Beam Facility

The Fermilab Test Beam Facility is a world class facility for testing and characterizing particle detectors. The facility has been in operation since 2005 and has undergone significant upgrades in the last two years. A second beam line with cryogenic support has been added and the facility has adopted the MIDAS data acquisition system. The facility also recently added a cosmic telescope test stand and improved tracking capabilities. With two operational beam lines, the facility can deliver a variety of particle types and momenta ranging from 120 GeV protons in the primary beam line down to 200 MeV particles in the tertiary beam line. In addition, recent work has focused on analyzing the beam structure to provide users with information on the data they are collecting. With these improvements, the Fermilab Test Beam facility is capable of supporting High Energy physics applications as well as industry users. The upgrades will be discussed along with plans for future improvements.   

Overview of a new compact and portable $x$-pinch radiation source generator (200-ka, 200-ns) for physics and industry applications.

The $x$-pinch radiation source generator has many proven applications in plasma backlighting, phase-contrast imaging of biological species, and more. We will briefly overview our new compact and portable $x$-pinch driver recently designed and tested at the Idaho Accelerator Center [1]. The up-to-date $x$-pinch radiation data will be presented and discussed. Our $x$-pinch driver is very easy to operate, require no or minimum maintenance, and can be easily relocated where a compact and portable $x$-pinch radiation source is wanted. [1]. R.~Shapovalov and R. Spielman, ``Shirt-Circuit test data of a new 2-LTD-Brick $x$-pinch driver at the Idaho Accelerator Center,'' in Proc. of Pulsed Power Conference (submitted), Austin, TX, May 2015.   

Maximizing Number of Passes in Recirculating Energy Recovery Linacs

The next generation of high energy recirculating linear accelerators (RLAs) will rely on the energy recovery (ER) process for their extreme high current operation. Here, we discuss optimum design of multi-pass linac optics for an RLA based on a large scale superconducting linac. Initial strategy used in the design of 60 GeV, 6 pass RLA for the LHeC, has been extended to 10 passes for the proposed CEBAF ER experiment. The presented optimization scheme addresses overall beam transport performance, as well as specific beam dynamics issues, such as, beam stability due to collective effects.