We have developed a novel and highly radiation-tolerant n-in-p silicon microstrip sensor for very high radiation environments such as in the Super Large Hadron Collider. The sensors are designed for ...a fluence of 1×10
15
neq/cm
2 and are fabricated from p-type, FZ, 6
in. (150
mm) wafers onto which we lay out a single 9.75
cm×9.75
cm large-area sensor and several 1
cm×1
cm miniature sensors with various n-strip isolation structures. By evaluating the sensors both pre- and post-irradiation by protons and neutrons, we find that the full depletion voltage evolves to approximately 800
V and that the n-strip isolation depends on the p
+ concentration. In addition, we characterize the interstrip resistance, interstrip capacitance and the punch-through-protection (PTP) voltage. The first fabrication batch allowed us to identify the weak spots in the PTP and the stereo strip layouts. By understanding the source of the weakness, the mask was modified accordingly. After modification, the follow-up fabrication batches and the latest fabrication of about 30 main sensors and associated miniature sensors have shown good performance, with no sign of microdischarge up to 1000
V.
We are developing n
+-in-p, p-bulk and n-readout, microstrip sensors, fabricated by Hamamatsu Photonics, as a non-inverting radiation hard silicon detector for the ATLAS tracker upgrade at the ...super-LHC (sLHC) proposed facility. The bulk radiation damage after neutron and proton irradiations is characterized with the leakage current, charge collection and full depletion voltage. The detectors should provide acceptable signal, signal-to-noise ratio exceeding 15, after the integrated luminosity of 6000
fb
−1, which is twice the sLHC integrated luminosity goal.
We are developing n
+-in-p, p-bulk and n-readout, microstrip sensors as a non-inverting radiation hard silicon detector for the ATLAS Tracker Upgrade at the super LHC experiment. The surface ...radiation damages of the sensors fabricated by Hamamatsu Photonics are characterized on the interstrip capacitance, interstrip resistance and punch-through protection evolution. The detector should provide acceptable strip isolation, exceeding the input impedance of the signal readout chip ∼1
kΩ, after the integrated luminosity of 6
ab
−1, which is twice the luminosity goal.
The ATLAS collaboration R&D group “Development of
n-in-
p Silico
n Sensors for very high radiation environment” has developed single-sided
p-type 9.75
cm×9.75
cm sensors with an
n-type readout strips ...having radiation tolerance against the 10
15 1-MeV neutron equivalent (n
eq)/cm
2 fluence expected in the Super Large Hadron Collider. The compiled results of an evaluation of the bulk and strip parameter characteristics of 19 new non-irradiated sensors manufactured by Hamamatsu Photonics are presented in this paper. It was verified in detail that the sensors comply with the technical specifications required before irradiation. The reverse bias voltage dependence of various parameters, frequency dependence of tested capacitances, and strip scans of more than 23,000 strips as a test of parameter uniformity and strip quality over the whole sensor area have been carried out at Stony Brook University, Cambridge University, University of Geneva, and Academy of Sciences of CR and Charles University in Prague. No openings, shorts, or pinholes were observed on all tested strips, confirming the high quality of sensors made by Hamamatsu Photonics.
The ATLAS experiment is preparing for the planned luminosity upgrade of the LHC (the super-luminous LHC or sLHC) with a programme of development for tracking able to withstand an order of greater ...magnitude radiation fluence and much greater hit occupancy rates than the current detector. This has led to the concept of an all-silicon tracker with an enhanced performance pixel-based inner region and short-strips for much of the higher radii. Both sub-systems employ many common technologies, including the proposed “stave” concept for integrated cooling and support. For the short-strip region, use of this integrated stave concept requires single-sided modules mounted on either side of a thin central lightweight support.
Each sensor is divided into four rows of 23.82
mm length strips; within each row, there are 1280 strips of 74.5μm pitch. Well over a hundred prototype sensors are being delivered by Hamamatsu Photonics (HPK) to Japan, Europe and the US.
We present results of the first 20 chip ABCN25 ASIC hybrids for these sensors, results of the first prototype 5120 strip module built with 40 ABCN25 read-out ASICs, and the status of the hybrids and modules being developed for the ATLAS tracker upgrade stave programme.
A measurement of splitting scales, as defined by the kT clustering algorithm, is presented for final states containing a W boson produced in proton--proton collisions at a centre-of-mass energy of 7 ...TeV. The measurement is based on the full 2010 data sample corresponding to an integrated luminosity of 36 pb-1 which was collected using the ATLAS detector at the CERN Large Hadron Collider. Cluster splitting scales are measured in events containing W bosons decaying to electrons or muons. The measurement comprises the four hardest splitting scales in a kT cluster sequence of the hadronic activity accompanying the W boson, and ratios of these splitting scales. Backgrounds such as multi-jet and top-quark-pair production are subtracted and the results are corrected for detector effects. Predictions from various Monte Carlo event generators at particle level are compared to the data. Overall, reasonable agreement is found with all generators, but larger deviations between the predictions and the data are evident in the soft regions of the splitting scales.
The production of W bosons in association with two jets in proton-proton collisions at a centre-of-mass energy of sqrt(s)=7 TeV has been analysed for the presence of double-parton interactions using ...data corresponding to an integrated luminosity of 36/pb, collected with the ATLAS detector at the LHC. The fraction of events arising from double-parton interactions, fDP(D) has been measured through the momentum balance between the two jets and amounts to fDP(D) = 0.08 +- 0.01 (stat.) +- 0.02 (sys) for jets with transverse momentum PT > 20 GeV and rapidity |y|<2.8. This corresponds to a measurement of the effective area parameter for hard double-parton interactions of \sigma_eff = 15 +- 3 (stat.) +5 -3 (sys.) mb.
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