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ILC DAQ

ILC DAQ. JJRussell. What Can Be Said At This Time ?. Terminology - Front-End vs Back-End Broad shape of the DAQ Management and Social Issues Summary. Front-End vs Back-End. The Front-End is defined as The portion of the DAQ running at the beam-bucket rate The Back-End is defined as

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ILC DAQ

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  1. ILC DAQ JJRussell

  2. What Can Be Said At This Time ? • Terminology - Front-End vs Back-End • Broad shape of the DAQ • Management and Social Issues • Summary

  3. Front-End vs Back-End • The Front-End is defined as • The portion of the DAQ running at the beam-bucket rate • The Back-End is defined as • The asynchronous portion responsible for • Collecting the data during inter-spill time • Organizing the data (event-building) • Too early to say much about the back-end • Extremely sensitive to available technology, except… • Debate of Commercial-Off-the-Shelf vs Custom, both have issues • COTS - failure to live up to expectations • Custom - expensive, long lead times

  4. Broad Shape of the DAQ • Duty cycle is the main driver • Now that it is known, can work with it • Main Features • Heavy buffering in the front-end • No hardware triggering

  5. Front-End • Luminosity/backgrounds force front-end buffering • Likely a fixed depth per channel • Likely tight due to a number of constraints • Buffer usage can be controlled either by • Central Trigger • Local Autonomous Decision • The latter is the choice of front-end architects • Puts a burden to get the assumptions on occupancy correct • If beginning of train noisy, will eat all the buffering

  6. Front-End - Continued • Almost certainly controlled by FPGA & ASICs • Opening guns in where to put functionality • Purpose built devices • General purpose CPUs • Power Issues • With this much stuff on the detector • Power will be an issue • Front-Ends gated off during inter-spill time

  7. Front-End - Continued • Process Control Issues • The FPGA/ASIC code is complicated • Good code management techniques must be adopted • Revision tracking, particularly in the field • Lead-time / serialization could be a major problem • Test systems must be taken seriously, both by • DAQ providing a usable system • Subsystems using it • CALICE gave a nice example of how this might work

  8. Front-End - Continued • Emphasize uniformity of front-end design • Front-End talks indicate the same general nature of the data • Need to translate this into uniformity of DAQ interface • Will greatly simplify the DAQ • Need a mechanism to achieve this • Communicate, don’t impose • Arbitration process to resolve differences

  9. No Hardware Trigger • Made possible by • Low duty cycle • Advances in technology • Bandwidth • Memory • Software filtering will control the data volume • A back-end problem • Once decided upon, likely no turning back

  10. Management / Social Issues • Team composition will be a mixture of • Cross-disciplinarians in Electronics/DAQ/Physics • Domain-specific engineers • Team composition will evolve with time • Design / Building / Commissioning / Operation • Getting a good set of requirements and solid interfaces is important, but… • Flexibility must be part of the game plan

  11. Management / Social Issues • Need to recognize the global nature of this enterprise • Global Detector Network provides a framework to minimize the importance of site selection • Allows detector to be operated from a virtual control room • If want this, must take it seriously from the beginning

  12. Summary • Need to stay in touch with • Front-End Architectures • Give uniformity at least a fighting chance • Machine Parameters • Number of buckets and bucket spacing have a large impact on the DAQ • Machine / Detector Interface • What information from the detector is useful to the accelerator operators • How should it be exchanged

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