CMS Tracker module / hybrid tests and DAQ development for the HL-LHC S. Mersi, G. Auzinger georg.auzinger@cern.ch 1
Outline Reminder: the Ph2 CMS Tracker upgrade pt Modules: principle, elements, electronics DAQ System: components, architecture, prototypes Testing activities: test stands, software, commissioning, towards production Summary & Outlook 2
Reminder: Ph2 Tracker upgrade I why upgrade? HL-LHC will increase luminosity by factor of ~10 leads to higher pile-up (-> 140-200) -> need detector with finer granularity and more read-out channels (binary readout) need more radiation-hard sensors need to include tracker information in the L1 trigger -> pt modules need to run at higher trigger rate -> need more bandwidth for read-out as we are at it: let s build a lighter tracker that consumes less power and can run cold at -20C let s improve the overall tracking performance & implement latest technologies optimize layout -> completely replace the tracker see Duccio s Talk yesterday 3
The pt modules: the principle contribution to the L1 trigger requires tracker hits @ 40MHz all hits would exceed bandwidth limits & complicate tracking only send high-pt hits to trigger: modules need to detect high momentum tracks: 1st proof of principle!! correlate hits on 2 closely spaced sensors connected to the same read-out chip -> stubs ship stubs to back-end electronics for fast track reconstruction 4
The pt modules: 2S / PS 2 strip sensors 5cm x 90 um r > 40 cm functional prototype of 2S module exists 1 strip (2.5cm x 100 um) 1 pixel (1.5mm x 100 um) r > 20 cm 5
The pt modules: electronics intelligent modules require lots of dedicated electronics: CBC (2S): dedicated ASIC to read and correlate strip-hits from 2 sensors hybrid : circuit that holds the chips, services & all routing (sensor to chip and chip to read-out) high-bandwidth, low power bi-directional optical link DC-DC converter 6 concentrator ASIC: data packing, stub-sorting
The pt modules: electronics intelligent modules require lots of dedicated electronics: SSA (ps): dedicated ASIC to read strip-hits from 1 sensor hybrid : circuit that holds the chips, services & all routing (sensor to chip and chip to read-out) DC-DC converter MPA (ps): ASIC to read pixel hits and correlate with strip hits high-bandwidth, low power bi-directional optical link concentrator ASIC: data packing, stub-sorting 7
DAQ system: concept use bi-directional optical link for control & read-out - high (asymmetric) bandwidth 2 dedicated read-out paths required (stubs + L1A data) via the same optical link (data formatting in concentrator ASIC) run track-reconstruction on the back-end electronics (low latency - very challenging!) S. Mersi 8
DAQ system: components F. Vasey utca as baseline for DTC development various approaches under study for L1 track finding communication with BE via TCP/IP 9 extremely challenging!!
DAQ development: prototypes have first functional 2S modules in hands: CBC2: correlation logic implemented, no stub information (just 1 bit) no concentrator ASIC: unsparsified data read-out via LVDS signals, no DC-DC converter DAQ board under development: CBC2 read-out implemented on GLIB board (utca AMC) for beam tests, R&D no track finding 2xCBC2 PCB hybrid (R&D) functional 8xCBC2 flex hybrid prototypes 10
Testing Activities now we have all these prototypes - what to do with them? testing (beam tests, RA source, cosmics) - need to understand behavior software development - control- & DAQ SW develop calibration & commissioning procedures study performance develop tests for production (QA) - need to qualify parts before assembly (~15k modules!!) -> have set up a dedicated lab for DAQ development, system- & module testing 11
Test stands @ CERN we are operating several test stands for R&D: system level: general R&D, testing, SW development only hybrids, no sensor, 2xCBC, 8xCBC utca infrastructure radioactive Sr90 source / cosmic rays: testing of assembled mini-pt-modules with particles scintillator trigger, HV supplies preparations for beam tests hybrid testing: development of quality assurance procedures for front-end hybrids signal induced via antenna setup 12
Control software development control system and DAQ FW need to interact with PC using IPBUS (FPGA) & uhal (PC) protocol to communicate via ethernet developed a set of libraries with abstracted methods for interaction of user with HW: BE electronics, CBC chips on top of these: calibration routines, testing routines, graphical user interface, full scale (distributed, CMS conform) data acquisition SW development started as summerstudent project large community of users and active developers PC GLIB card 13 user code DAQ SW Middleware uhal IPBUS HW/FPGA ethernet
Calibration & commissioning operation in the future requires understanding of steps necessary to calibrate and commission a sensor module: Vplus 160 140 spread of channels CBC only flags signals above a given threshold as hits: 120 100 80 - need to calibrate all channels to the same threshold (charge) 60 40 20 want to measure only signals induced by particles: 20 40 60 80 100 120 140 160 180 200 220 VCth Scurve_Be0_Fe0_Cbc1_Channel238 - threshold scan to suppress noise Efficiency 1 Scurve_Be0_Fe0_Cbc1_Channel238Vplus100 Entries 142 Mean 123.3 RMS 5.002 want to read the right data for each trigger 0.8 data - latency scan (time between event & arrival of Latency FE0 trigger) pipeline 1 event per cell trigger decision takes O(us) # of Hits 1000 800 600 400 0.6 0.4 h_module_latency_fe0 Entries 1840 Mean 5.239 RMS 0.6047 0.2 0 0 50 100 150 200 250 VCth 200 read-out 0 0 2 4 6 8 10 14 Latency
Understanding the performance prototypes allow to study behavior of individual components, spot issues, etc.. examples: observed stronger correlation of CBC channels than expected (depending on mode of operation) -> will be fixed in the next version spotted problems in I2C communication between BE electronics & CBC -> change resistors on hybrid observed shadow effect in CBC: chip in sensitive to amplifier overshoot -> will be fixed Count Probability 120 100 80 60 40 20 0.35 0.34 0.33 0.32 0.31 0.3 0.29 0.28 0.27 0.26 Fe0_Cbc0 Nhits Vcth: 78 Ω=50% -Data -Fit: 18% CM, Thr. 0.0 -Sim: 0% CM Fe0_Cbc0_h_Nhits Entries 2000 Mean 128.8 RMS 19.88 0 50 100 150 200 250 Hits Fe0_Cbc0 - Ωxy (logical AND) -ΩxΩy (uncorrelated) Fe0_Cbc0_p_ChargeSh Fe0_Cbc0_p_UncorrProb Entries 1.24002e+08 62001 Mean 82.980 Mean y y 0.2833 0.2972 RMS 59.03 102 RMS y y 0.02018 0.457 0.25 0 50 100 150 200 250 Strip Distance expected signal shadow signal 15 Latency
Preparations for beam tests cosmic ray setup allows operation similar to the conditions in beam test: external trigger, correct timing, properly set thresholds allows to commission and test everything before precious beam time next dates: June & November 15 16
Towards production Occupancy [%] 100 90 80 70 60 Front Pad Channels 50 40 for the final Ph2 outer tracker ~15 000 modules will have to be built quality assurance absolutely necessary: hybrids are a highly integrated piece - high trace density, lots of bonding bumps and components Occupancy [%] 100 90 80 70 60 50 40 30 20 10 Front Pad Channels 0 0 50 100 150 200 250 Pad Number 30 20 10 0 236 238 240 242 244 246 248 250 252 254 Pad Number Occupancy [%] 100 90 80 70 60 50 40 30 20 10 Back Pad Channels disconnected bumps 0 0 50 100 150 200 250 Pad Number can not afford to build a module with a hybrid that has faults (disconnected channels etc ) -> need to develop reliable procedure to test components / hybrids & and modules after each step of assembly idea: verify connectivity from sensor pad to chip via signal induced by antenna - should allow to spot disconnected channels group involved in definition of QA standards 17
Summary & Outlook CMS tracker needs complete replacement for HL-LHC era to cope with conditions features: higher trigger rate, contribution to L1 trigger, on-module pt discrimination, new DAQ & control system first prototype 2S modules exist CERN set up dedicated, well equipped lab future Activities: DAQ system development / testing SW framework development of commissioning procedures module / component / system testing present different test stands available lot s of interesting work to be done large community of users and developers in the project full size 2S module prototype to be tested this fall modules with irradiated sensors system-level tests: data packing algorithms, data-loss studies, etc integration of new components as they become available (CBC3, concentrator ASIC, DC-DC converters, optical links) expect first functional PS module prototypes in the nearer future: need to develop similar DAQ prototype / software 18
Backup: Flex Hybrid 19