R&D at LPHE/EPFL: SiPM and DAQ electronics

1. CHIPP Workshop on Detector R&D Geneva, 11.-12.June 2008 R&D at LPHE/EPFL: SiPM and DAQ electronics Guido Haefeli

2. Introduction Aim to maintain and enhance our current expertise in detector technology for the LHCb experiment: 1) Fast DAQ readout electronics TELL1 board: common 1 MHz readout board for LHCb ⇒ increase the readout speed to 40 MHz enabling fully software trigger scheme 2) Precision tracking system LHCb Inner Tracker: silicon micro-strip detector near beam pipe ⇒ move to scintillating fibre with SiPM readout enabling large surface precision tracking

3. Current TELL1 • Digitization (VELO) • Synchronization (TTC) • Data compression (factor 10) • Buffering • Ethernet and IP formatting (framer), physical IF 24 x 1.28 Gbit/s = 30 Gbit/s GOL TLK2501 @1.6Gbit/s 4 x 1 Gbit/s = 4 Gbit/s Gigabit Ethernet with IP Data compression ~10

4. ~300 board to read out almost all sub-detectors in LHCb Vertex Locator Analogue links, use digitizer mezzanine cards Instead of optical receivers. All other sub-detectors use optical links

5. Requirements for LHCb upgrade • 40 times more data in SLHCb, needs many high speed serial links to cope with the necessary data bandwidth, for example 300 Gbit/s input and 40 Gbit/s output bandwidth is required (TELL1 x 10 in bandwidth). • Make use of the future Gigabit Bidirectional Trigger and Data link (GBT) developed by Cern as interconnect between the FE and the DAQ. • Minimize power consumption as it becomes critical with the dense integration of serial links, FPGA data processing and memory. • Minimize event building overhead in receiving PC by adaptation of network protocol (for example use Infiniband with RDMA) • Avoid event based network traffic (all sources send to one destination at the same time)! Sufficient buffering is needed. • Improve data reduction algorithm in terms of performance but also implementation of simulation (authomatic c-model generation) . • First level trigger information extraction possibility for intelligent event selection.

6. LHCb upgrade FE and DAQ

7. R&D plan for a new DAQ board • Study the implementation of the dense high speed interconnection part of the design and optimize for power consumption and signal integrity. • Acquire and extend knowledge of the implementation of zero-suppression algorithms using FPGAs and higher level hardware description languages (SystemC, CatapultC…). Simulation support for algorithm selection. • Evaluate the performance of different network protocols and link technologies. Build 4 x10 Gigabit Ethernet and 40 Gigabit Infiniband prototype demonstrator board.

8. Scintillating fibres read with SiPM • Scintillating fibres can be used not only for Calorimeters but also for precision trackers with small 250 µm thick fibres. • SiPM can be used as a very compact photon detector ⇒need multi-channel SiPM: Our Main InterestCollaboration with Hamamatsu commercially available single channel SiPM and prototype multi-channel SiPMT developed for us. One readout channel for 20x4 pixels, 32 channels

10. R&D plan and possible application R&D plan: • Study in detail properties of Hamamatsu multi-channel SiPM and optimize the geometry • Study optical coupling between fibres and SiPM • Test fibre tracker prototypes i.e. fibres and SiPM from different vendors (collaboration with Aachen) Application: • Near future, < 5 years Readout of EM calorimeter for a balloon experiment (PEBs: measurement of e+ spectrum) • Medium future, <10 years Unified Tracker System for SuperLHCb