Characteristics of irradiated silicon microstrip detectors with <100> and <111> substrates

In a program of developing radiation-hard silicon sensors for the LHC-ATLAS experiment, we have irradiated various types of silicon sensors with 12 CeV protons at KEK. Among the other properties, we made a comparative study of characteristics of the sensors with two wafer planes and . The studied sensors are p-on-n type, which satisfy the ATLAS-SCT specifications. Possible dependence on the substrate orientation could result from different dangling-bond configurations. The compared characteristics are the charge collection efficiency, interstrip capacitance, and noise levels. The noise levels were measured with a real ATLAS-SCT electronics system. A substantial difference is observed in the interstrip capacitance at ~10 kHz, while the difference is small at >1 MHz. The differences in the charge collection efficiency and in the noise levels appear to be small. (5 refs)

Beam study of irradiated ATLAS-SCT prototypes

Prototypes of ATLAS-SCT modules with ABCD readout chips were tested in a 4 GeV/c pion beam at KEK's proton synchrotron. Of both SCT module geometries - barrel and forward - three identical modules were placed in the beam. One module of each type had been irradiated to 3x10 sup 1 sup 4 protons/cm sup 2 in the CERN PS previous to the beam test. A method has been developed to reconstruct the time-resolved shaper pulse from the binary hit information, allowing a more detailed study of the timing properties of the ABCD. The present results will be compared to a simulation of the charge collection and Front End electronics response

Beamtest of nonirradiated and irradiated ATLAS SCT microstrip modules at KEK

Nonirradiated and irradiated ATLAS silicon microstrip barrel and endcap modules have been beamtested with 4-GeV/c pions. Pulse shapes confirmed the peaking time of the amplifier to be 22 ns with slight deterioration in the irradiated modules. Median charges saturated around 3.8 fC, both in the nonirradiated and the irradiated modules. Signal/noise ratios, using the noise estimates from the in-situ calibration, were >16 in the nonirradiated (>150 V) and >10 in the irradiated (>300 V) barrel modules. No excess common-mode noise was observed. (10 refs)

The silicon microstrip sensors of the ATLAS semiconductor tracker.

This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the Semiconductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd. supplied 92.2% of the 15,392 installed sensors, with the remainder supplied by CiS