123250095
Prototype studies and design considerations for the CLAS Region 2 drift chambers
Abstract The CEBAF Large Acceptance Spectrometer (CLAS) has recently been commissioned in Hall B of the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The six “Region 2” drift chambers, built by Old Dominion University with technical support from Jefferson Lab, are located between the coils of the CLAS super-conducting toroidal magnet. The endplates were constructed from non-conducting fiberglass in order to eliminate eddy-current forces during possible magnet quenches. The non-conducting endplate allowed the use of compact wire connecting and signal transfer hardware, thus minimizing the loss of acceptance of the Region 2 chambers. Wires were positioned by flared trumpet-shaped metal feedthroughs that were glued directly into precision holes drilled into the endplates. We report test results from two prototype chambers. A single-cell prototype proved general functionality of the endplate/feedthrough design and showed that the active area of the chamber starts approximately 10 mm from the end of the sense wire. A 36-cell prototype achieved a tracking resolution of better than 150 μm with various gas mixtures.
97513211
SPIN STRUCTURE FUNCTIONS OF THE DEUTERON
123285728
BoNus: Development and use of a radial TPC using cylindrical GEMs $
Abstract A specialized system of target and detector was developed at Jefferson Lab to provide new access to information about neutron structure from electron–neutron interactions. It allows identification and measurement of spectator protons produced in e - d → e - p s X scattering events. The detector is a radial time-projection chamber optimized for the acceptance of low-momentum protons. Gas gain is provided by three cascaded curved Gas Electron Multipliers (GEMs), the first application of GEMs in any configuration other than flat. This article provides details about the development and construction of the detector, its performance, and the analysis of the data from the successful running of its first physics experiment.
121886810
Experimental Results in DIS, SIDIS and DES from Jefferson Lab
Jefferson Lab’s electron accelerator in its present incarnation, with a maximum beam energy slightly above 6 GeV, has already enabled a large number of experiments expanding our knowledge of nucleon and nuclear structure (especially in Deep Inelastic Scattering—DIS—at moderately high x, and in the resonance region). Several pioneering experiments have yielded first results on Deeply Virtual Compton Scattering (DVCS) and other Deep Exclusive Processes (DES), and the exploration of the rich landscape of transverse momentum‐dependent (TMD) structure functions using Semi‐Inclusive electron scattering (SIDIS) has begun. With the upgrade of CEBAF to 12 GeV now underway, a significantly larger kinematic space will become available. The 12 GeV program taking shape will complete a detailed mapping of inclusive, TMD and generalized distribution functions for quarks, antiquarks and gluons in the valence region and beyond.
7834320
MEASUREMENTS OF THE NUCLEON FORM FACTORS AT LARGE MOMENTUM TRANSFERS
New measurements of the electric GE(Q2) and magnetic GM(Q2) form factors of the nucleons are reported. The proton data cover the Q2 range from 1.75 to 8.83 (GeV/c)2 and the neutron data from 1.75 to 4.00 (GeV/c)2, more than doubling the range of previous data. Scaled by the dipole fit, GD(Q2), the results forGMp(Q2) /?pGD(Q2) decrease smoothly from 1.05 to 0.92, while GEp(Q2)/GD(Q2)is consistent with unity. The preliminary results for GMn(Q2) /?nGD(Q2) are consistent with unity, while GEn is consistent with zero at all values of Q2.
117907050
Structure Functions of Bound Neutrons
We describe an experiment measuring electron scattering on a neutron bound in deuterium with coincident detection of a fast, backward‐going spectator proton. Our data map out the relative importance of the pure PWIA spectator mechanism and final state interactions in various kinematic regions, and give a first glimpse of the modification of the structure function of a bound neutron as a function of its off‐shell mass. We also discuss a new experimental program to study the structure of a free neutron by extending the same technique to much lower spectator momenta.
8682177
First Beam Test Characterisation of a 3D-stc Silicon Short Strip Detector
The planned upgrade to the CERN Large Hadron Collider (LHC), the Super-LHC (sLHC) will increase its luminosity by a factor of ten. This necessitates the development of silicon tracking detectors that are significantly more radiation resistant than the ones employed at the LHC. Currently, new detector technologies are being developed to cope with the increased levels of radiation damage at the sLHC. A possible radiation hard option for silicon short strip devices (SSD) in the inner layers of sLHC trackers are 3-D detectors with rows of columnar electrodes processed into the bulk material. These are joined together to form strips. While the excellent radiation hardness of this design has been proven before in lab experiments, a 3-D SSD prototype has now been investigated for the first time in a beam test with pions of a nominal energy of 180 GeV. The use of analog LHC-speed electronics, a beam telescope and time-resolved measurements allowed for detailed studies of the signal behavior on the hit strip and its neighboring strips. Charge collection and efficiency were as well measured with respect to time and point of incidence of the beam particles on the detector. The results of these measurements are presented in this paper.
26356337
Investigation of 3D silicon microstrip detectors for the sLHC
An increase of the luminosity of the Large Hadron Collider (LHC) at CERN is foreseen around 2017 by about an order of magnitude. This will translate into a largely increased radiation dose, with which the present trackers can not cope. The development of radiation-hard silicon detectors is required for the innermost tracking layers. One option for radiation-hard silicon sensors is the 3D technology, where columnar electrodes are etched, perpendicular to the surface, into the silicon bulk. In this paper we investigated 3D single type columns (3D-STC) detectors which were irradiated with 26 MeV protons to fluences up to 2.5×10 15 1-MeV equivalent neutrons(Neq)/cm 2 which corresponds to fluences expected at the inner tracking layers of the sLHC. Before and after irradiations the sensors were tested with a beta-source setup to measure and quantify the radiation induced damage.
41938556
Short Strips for the sLHC: A P-Type Silicon Microstrip Detector in 3-D Technology
The luminosity upgrade of the Large Hadron Collider (LHC), the sLHC, will constitute an extremely challenging radiation environment for tracking detectors. With respect to the LHC, large improvements in radiation hardness are required. In this paper, we investigated the expected radiation hardness of the 3-D-design, where rows of 3-D-columns are etched in substrate material and joined together to form strips. To investigate the feasibility of 3-D silicon strip detectors (SSD) for the sLHC, we have built prototype modules using 3-D single type column (3-D-STC) strip detectors with short strips and front-end electronics from the present ATLAS SemiConductor Tracker (SCT). The modules were tested with a beta source setup before and after irradiation to sLHC fluences with 26 MeV protons. We report on the performance of these 3-D-modules, compare it to the results prior to irradiation, and draw conclusions about options for using 3-D SSD detectors for tracking at the sLHC.
25295548
Short strips for the SLHC: A P-Type Silicon microstrip detector in 3D-technology
The luminosity upgrade of the Large Hadron Collider (LHC), the sLHC, will constitute an extremely challenging radiation environment for tracking detectors. With respect to the LHC, massive improvements in radiation hardness are required. In this paper we investigate the superior radiation hardness of the 3D-design, where rows of 3D-columns are etched in substrate material and joined together to form strips. To demonstrate the feasibility of 3D silicon strip detectors (SSDs) for the sLHC, we have built prototype modules using 3D single type column (3D-STC) strip detectors with short strips and front-end electronics from the present ATLAS SemiConductor Tracker (SCT). The modules were tested with a beta source setup before and after irradiation to sLHC fluences with 26 MeV protons. We report on the performance of these 3D-modules, compare it to the results prior to irradiation, and draw conclusions about options for using 3D SSDs for tracking at the sLHC.