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.
109063356
Laser characterisation of a 3D single-type column p-type prototype module read out with ATLAS SCT electronics
In this paper measurements of a 3D single-type column (3D-stc) microstrip silicon device are shown. The 3D-stc sensor has n-type columns in p-type substrate. It has been connected to an ATLAS SCT ABCD3T chip and is readout with ATLAS SCT electronics at 40 MHz. Spatial measurements were done with a laser setup to investigate the expected low field region in 3D devices. An influence of the p-stops on the collected charge has been observed.
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.
121972934
Signal and charge collection efficiency of a p-type STC 3D-detector irradiated to sLHC-fluences, read out with 40 MHz
Abstract Using ATLAS SCT front-end electronics, we have built a 3D prototype detector module which was then irradiated to a fluence of 1 × 10 15 n eq / cm 2 . After irradiation, the module was tested with an IR-laser yielding relative CCE measurements with high spatial resolution. Position-sensitive measurements are required, as from simulation the STC 3D-detector geometry is expected to have low-field regions with lower CCE. We report on the performance of the irradiated 3D-module read out at 40 MHz, compare it to the unirradiated behaviour and draw conclusions about the feasibility of using such detectors for tracking at the sLHC.
109469281
3D silicon strip detectors
Abstract While the Large Hadron Collider (LHC) at CERN has started operation in autumn 2008, plans for a luminosity upgrade to the Super-LHC (sLHC) have already been developed for several years. This projected luminosity increase by an order of magnitude gives rise to a challenging radiation environment for tracking detectors at the LHC experiments. Significant improvements in radiation hardness are required with respect to the LHC. Using a strawman layout for the new tracker of the ATLAS experiment as an example, silicon strip detectors (SSDs) with short strips of 2–3 cm length are foreseen to cover the region from 28 to 60 cm distance to the beam. These SSD will be exposed to radiation levels up to 10 15 N eq / cm 2 , which makes radiation resistance a major concern for the upgraded ATLAS tracker. Several approaches to increasing the radiation hardness of silicon detectors exist. In this article, it is proposed to combine the radiation hard 3D-design originally conceived for pixel-style applications with the benefits of the established planar technology for strip detectors by using SSDs that have regularly spaced doped columns extending into the silicon bulk under the detector strips. The first 3D SSDs to become available for testing were made in the Single Type Column (STC) design, a technological simplification of the original 3D design. With such 3D SSDs, a small number of prototype sLHC detector modules with LHC-speed front-end electronics as used in the semiconductor tracking systems of present LHC experiments were built. Modules were tested before and after irradiation to fluences of 10 15 N eq / cm 2 . The tests were performed with three systems: a highly focused IR-laser with 5 μ m spot size to make position-resolved scans of the charge collection efficiency, an Sr 90 β -source set-up to measure the signal levels for a minimum ionizing particle (MIP), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of the results obtained with 3D-STC-modules.
120247908
3D stc sensors with different strip isolation schemes and substrate materials
Abstract For the innermost layers of the foreseen upgrade to the ATLAS tracker, charge trapping will be the main limitation in terms of the sensor lifetime. A possible solution to the degradation of the charge collection efficiency (CCE) could be the use of 3D detectors. In 3D detectors the electrodes are processed not just at the surface of the sensor, but they extend partly or completely through the silicon bulk. The distance between the columnar electrodes of 3D detectors can be adjusted to the expected fluence range. We designed and constructed prototype modules comprising ATLAS SCT front-end electronics and 3D single-type column (stc) p-type strip detectors with different strip isolation techniques and different substrate materials. With a strip length of 18.4 mm these sensors could be a radiation hard option for the innermost short strip region of the inner detector in the upgraded ATLAS experiment. We characterised these 3D stc p-type sensors in terms of their noise behaviour and hence their effective capacitance as a function of applied bias voltage at a read-out speed of 40 MHz which is also anticipated for sLHC. Employing an IR laser and automated x – y stages with micrometer resolution we characterised the sensors regarding the CCE in dependence of the bias voltage and the IR laser position relative to the sensors before irradiation.
119187401
Experimental study of isovector spin sum rules
We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for $0.05<2.92$ GeV$^2$. The integral is fit to extract the twist-4 element $$f_{2}^{p-n}$$ which is large and negative. Systematic studies of this higher twist analysis establish its legitimacy at $$Q^{2}$$ around 1 GeV$$^{2}$$. We also extracted the isovector part of the generalized forward spin polarizability $$\gamma_{0}$$. Although this quantity provides a robust test of Chiral Perturbation Theory, our data disagree with the calculations.
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.