In:
Journal of Instrumentation, IOP Publishing, Vol. 18, No. 03 ( 2023-03-01), p. T03008-
Abstract:
The ATLAS experiment is constructing new all-silicon inner
tracking system for HL-LHC. The strip detectors cover the radial extent of 40 to 100 cm. A new approach is adopted to use p-type
silicon material, making the readout in n + -strips, so-called
n + -in-p sensors. This allows for enhanced radiation tolerance
against an order of magnitude higher particle fluence compared to the LHC. To cope with varying hit rates and occupancies as a
function of radial distance, there are two barrel sensor types, the short strips (SS) for the inner 2 and the long strips (LS) for the
outer 2 barrel cylinders, respectively. The barrel sensors exhibit a square, 9.8 × 9.8 cm 2 , geometry, the largest possible
sensor area from a 6-inch wafer. The strips are laid out in parallel with a strip pitch of 75.5 μm and 4 or 2 rows of
strip segments. The strips are AC-coupled and biased via polysilicon resistors. The endcap sensors employ a
“stereo-annulus” geometry exhibiting a skewed-trapezoid shapes with circular edges. They are designed in 6 unique shapes, R0 to R5,
corresponding to progressively increasing radial extents and which allows them to fit within the petal geometry and the 6-inch wafer
maximally. The strips are in fan-out geometry with an in-built rotation angle, with a mean pitch of approximately 75 μm and
4 or 2 rows of strip segments. The eight sensor types are labeled as ATLAS18xx where xx stands for SS, LS, and R0 to R5. According to
the mechanical and electrical specifications, CAD files for wafer processing were laid out, following the successful designs of
prototype barrel and endcap sensors, together with a number of optimizations. A pre-production was carried out prior to the full
production of the wafers. The quality of the sensors is reviewed and judged excellent through the test results carried out by vendor.
These sensors are used for establishing acceptance procedures and to evaluate their performance in the ATLAS collaboration, and
subsequently for pre-production of strip modules and stave and petal structures.
Type of Medium:
Online Resource
ISSN:
1748-0221
DOI:
10.1088/1748-0221/18/03/T03008
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
2023
detail.hit.zdb_id:
2235672-1
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