8 research outputs found
Application of Time Projection Chambers with GEMs and Pixels to WIMP Searches and Fast Neutron Detection
We present work on the detection of neutral particles via nuclear recoils in
gas-filled Time Projection Chambers (TPCs). We employ Gas Electron Multipliers
(GEMs) to amplify the signal and silicon pixel electronics to detect the
avalanche charge. These technologies allow ionization in the target gas to be
detected with low noise, improved position and time resolution, and high
efficiency. We review experimental results obtained in previous years, and
report on ongoing simulation studies and construction of the first prototype at
the University of Hawaii. We also present prospects of using such detectors to
perform direction-sensitive searches for WIMP dark matter and fast neutron from
fissionable material.Comment: Proceedings of 2nd International Conference on Technology and
Instrumentation in Particle Physics (TIPP 2011), to be published in Physics
Procedia, 8 pages, 9 figure
A time resolved study of injection backgrounds during the first commissioning phase of SuperKEKB
We report on measurements of beam backgrounds during the first commissioning
phase of the SuperKEKB collider in 2016, performed with the plastic
scintillator and silicon photomultiplier-based CLAWS detector system. The
sub-nanosecond time resolution and single particle detection capability of the
sensors allow bunch-by-bunch measurements, enable CLAWS to perform a novel time
resolved analysis of beam backgrounds, and make the system uniquely suited for
the study of injection backgrounds. We present measurements of various aspects
of regular beam background and injection backgrounds which include time
structure and decay behavior of injection backgrounds, hit-energy spectra and
overall background rates. These measurements show that the elevated background
rates following an injection generally last for several milliseconds, with the
majority of the background particles typically observed within the first 500
us. The injection backgrounds exhibit pronounced patterns in time, connected to
betatron and synchrotron oscillations in the accelerator rings. The frequencies
of these patterns are determined from detector data.Comment: 19 pages, 12 figures, published in EPJ
Dark sectors 2016 Workshop: community report
This report, based on the Dark Sectors workshop at SLAC in April 2016,
summarizes the scientific importance of searches for dark sector dark matter
and forces at masses beneath the weak-scale, the status of this broad
international field, the important milestones motivating future exploration,
and promising experimental opportunities to reach these milestones over the
next 5-10 years
Measurement of the J/ photoproduction cross section over the full near-threshold kinematic region
We report the total and differential cross sections for
J
/
ψ
photoproduction with the large acceptance GlueX spectrometer for photon beam energies from the threshold at 8.2 GeV up to 11.44 GeV and over the full kinematic range of momentum transfer squared,
t
. Such coverage facilitates the extrapolation of the differential cross sections to the forward (
t
=
0
) point beyond the physical region. The forward cross section is used by many theoretical models and plays an important role in understanding
J
/
ψ
photoproduction and its relation to the
J
/
ψ
-proton interaction. These measurements of
J
/
ψ
photoproduction near threshold are also crucial inputs to theoretical models that are used to study important aspects of the gluon structure of the proton, such as the gluon generalized parton distribution of the proton, the mass radius of the proton, and the trace anomaly contribution to the proton mass. We observe possible structures in the total cross section energy dependence and find evidence for contributions beyond gluon exchange in the differential cross section close to threshold, both of which are consistent with contributions from open-charm intermediate states
Strange Hadron Spectroscopy with Secondary KL Beam in Hall D
Final version of the KLF Proposal [C12-19-001] approved by JLab PAC48. The intermediate version of the proposal was posted in arXiv:1707.05284 [hep-ex]. 103 pages, 52 figures, 8 tables, 324 references. Several typos were fixedWe propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with the GlueX experimental setup for strange hadron spectroscopy. The superior CEBAF electron beam will enable a flux on the order of , which exceeds the flux of that previously attained at SLAC by three orders of magnitude. The use of a deuteron target will provide first measurements ever with neutral kaons on neutrons. The experiment will measure both differential cross sections and self-analyzed polarizations of the produced , , , and hyperons using the GlueX detector at the Jefferson Lab Hall D. The measurements will span CM from to 0.95 in the range W = 1490 MeV to 2500 MeV. The new data will significantly constrain the partial wave analyses and reduce model-dependent uncertainties in the extraction of the properties and pole positions of the strange hyperon resonances, and establish the orbitally excited multiplets in the spectra of the and hyperons. Comparison with the corresponding multiplets in the spectra of the charm and bottom hyperons will provide insight into he accuracy of QCD-based calculations over a large range of masses. The proposed facility will have a defining impact in the strange meson sector through measurements of the final state system up to 2 GeV invariant mass. This will allow the determination of pole positions and widths of all relevant -,-,-,-, and -wave resonances, settle the question of the existence or nonexistence of scalar meson and improve the constrains on their pole parameters. Subsequently improving our knowledge of the low-lying scalar nonet in general