SCT module and quality assurance

For cost and schedule reasons, the tracker will be constructed from spare modules of the ATLAS semiconductor strip tracker (SCT). In October 2018, the SCT Institute Board has kindly agreed to allow FASER to use 80 of the available spare barrel modules [1]. Figure below shows a barrel module with 6 on-detector ASICs per side, which are integrated into the module. These ``ABCD'' ASICs [2] are the first stage of the detector readout and control the module's hit threshold and overall configuration. The SCT modules have proven their reliability in ATLAS during LHC Runs 1 and 2, operating without problems and delivering excellent physics performance.


The basic tracker design is three tracking stations, located at the front, center and back of the spectrometer, where each station contains three planes of SCT modules. An SCT module comprises two pairs of silicon strip detectors glued back-to-back to a central thermal pyrolytic graphite (TPG) baseboard. The modules will be oriented to optimize measurement precision in the magnetic bending plane; a stereo angle of 20 mrad between the two sides allows track position measurements in the non-precision direction as well. The strip pitch is 80 μm allowing track position resolution in the precision coordinate of order 17 μm per plane (assuming 4 SCT planes, and perfect detector alignment). The resolution in the non-precision coordinate is about 580 μm [3].

The number of tracking planes per station is chosen to give high efficiency and sufficient redundancy, while limiting the amount of material inside the tracking volume. To simplify the system, all three tracking stations have an identical design. The design is also matched to the number of available SCT spare modules. Each SCT module is 6 cm 12 cm and the tracking plane is made of 8 modules, giving a square of about 24 cm 24 cm covering the full active area of the detector (a 10 cm-radius circle determined by the magnet aperture). Each SCT module has 768 readout channels per side, giving the full tracker system a total of 111 10^3 channels.

Quality assuarance to choose the SCT modules for FASER experiment had started since Janually 2019, and successfully identified more than 80 modules in March 2019. More detail can be found here.

[1] Nucl.Instrum. Meth.A568(2006) 642671.

[2] Nucl. Instrum. Meth.A552(2005) 292328.

[3] JINST9(2014) P08009, arXiv:1404.7473 [hep-ex].

Module frame

Fabrication of the 1st prototype to be finished by 3rd week of July.

  • In 4th week of June, design of frame for prototype was fixed.
  • In 5th week of June, the raw material would be ordered.
  • In 5th week of June, fabrication drawings would be finalized.
Any modification should be identified by end of September.
  • Space in B161 for commissioning would be available after 15th Aug.
  • Start to integrate with available equipment and prototypes.
  • Try to get all components ready from the beginning of September.
Full production (9+spares) would be finished by end of November


Flexible cable and patch panel

Link to documentation in Workspace and overleaf

Trigger Readout Board

Link to documentation in Workspace and overleaf

-- HidetoshiOtono - 2019-06-20

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf DPNC420_01A.pdf r1 manage 1344.9 K 2019-06-26 - 07:47 HidetoshiOtono Layout for adapter board
PDFpdf DPNC420_01_01A_A60.pdf r1 manage 1467.7 K 2019-06-26 - 07:48 HidetoshiOtono Circuit diagram for adapter board
Unknown file formatdxf FASER_Patch_Panel.dxf r1 manage 2370.8 K 2019-06-25 - 23:48 HidetoshiOtono  
PDFpdf FASER_Patch_Panel.pdf r1 manage 1479.8 K 2019-06-25 - 23:49 HidetoshiOtono  
Unknown file formatdxf FASER_flexible_cable.dxf r1 manage 380.6 K 2019-06-25 - 23:47 HidetoshiOtono  
PDFpdf FASER_flexible_cable.pdf r1 manage 404.6 K 2019-06-25 - 23:47 HidetoshiOtono  
PDFpdf HIH-4000-003.pdf r1 manage 244.4 K 2019-07-01 - 12:51 HidetoshiOtono  
PDFpdf NTC-103JT-025.pdf r1 manage 447.7 K 2019-07-01 - 12:51 HidetoshiOtono  
JPEGjpg module-letters.jpg r1 manage 113.7 K 2019-06-20 - 15:02 HidetoshiOtono  

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Topic revision: r6 - 2019-07-01 - HidetoshiOtono
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