IEEE : Cooling and Timing Tests of the ATLAS Fast TracKer VME Boards

Sottocornola, S.; Seiss, T.; Negri, A.; Long, J.D.; Roda, C.; Holmes, T.; Gentsos, C.; Lanza, A.; Calabro, D.; Brost, E.; Annovi, A.; Iizawa, T.; Biesuz, N.V.; Mastrandrea, P.; Calvetti, M.; Romano, E.; Horyn, L.; Piendibene, M.; Maznas, I.

doi:10.1109/TNS.2021.3089048

ATLAS Note
Report number	arXiv:2010.14456 ; ATL-DAQ-PROC-2020-020
Title	Cooling and Timing Tests of the ATLAS Fast TracKer VME Boards
Author(s)	Sottocornola, S. (INFN, Pavia) ; Annovi, A. (Pisa U. ; INFN, Pisa) ; Biesuz, N.V. (Pisa U. ; INFN, Pisa) ; Brost, E. (Brookhaven Natl. Lab.) ; Calvetti, M. (Pisa U. ; INFN, Pisa) ; Gentsos, C. (CERN) ; Holmes, T. (Chicago U.) ; Horyn, L. (Chicago U.) ; Iizawa, T. (U. Geneva (main)) ; Lanza, A. (INFN, Pavia) ; Long, J.D. (Illinois U., Urbana (main)) ; Mastrandrea, P. (Pisa U. ; INFN, Pisa) ; Maznas, I. (Aristotle U., Thessaloniki) ; Negri, A. (INFN, Pavia) ; Calabro, D. (INFN, Pavia) ; Piendibene, M. (Pisa U. ; INFN, Pisa) ; Roda, C. (Pisa U. ; INFN, Pisa) ; Romano, E. (INFN, Pavia) ; Seiss, T. (Chicago U.)
Corporate Author(s)	The ATLAS collaboration
Publication	2021-07-02
Imprint	15 Oct 2020
Number of pages	8
Note	Real Time 2020 conference, 8 pages
In:	IEEE Trans. Nucl. Sci. 68 (2021) 2051-2058
In:	22nd IEEE Real Time Conference, Virtual, Vietnam, 12 - 23 Oct 2020, pp.2051-2058
DOI	10.1109/TNS.2021.3089048 (publication)
Subject category	Particle Physics - Experiment ; Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	Associative Memories ; electronics cooling ; FPGA ; particle tracking ; temperature control ; timing
Abstract	The Fast Tracker (FTK) is an ATLAS trigger upgrade built for full event, low-latency, high-rate tracking. The FTK core, made of 9U VME boards, performs the most demanding computational task. The Associative Memory Board Serial Link Processor (AMB) and the Auxiliary card (AUX), plugged on the front and back sides of the same VME slot, constitute the Processing Unit (PU), which finds tracks using hits from 8 layers of the inner detector. The PU works in pipeline with the Second Stage Board (SSB), which finds 12-layer tracks by adding extra hits to the identified tracks. In the designed configuration, 16 PUs and 4 SSBs are installed in a VME crate. The high power-consumption of the AMB, AUX and SSB (respectively of about 250 W, 70 W and 160 W per board) required the development of a custom cooling system. Even though the expected power consumption for each VME crate of the FTK system is high compared to a common VME setup, the 8 FTK core crates will use $\approx$ 60 kW, which is just a fraction of the power and the space needed for a CPU farm performing the same task. We report on the integration of 32 PUs and 8 SSBs inside the FTK system, on the infrastructures needed to run and cool them, and on the tests performed to verify the system processing rate and the temperature stability at a safe value.
Copyright/License	publication: (License: CC-BY-4.0) preprint: (License: CC-BY-4.0)