Notes on BCD by N.Toge (Jan. 5, 2005) Instrumentation and Control
General: Toge feels that many subsections within this part have already gone well into RDR-type descriptions rather than BCD. However, before proceeding further, a few points are worth a GDE-wide review and consensus forming (If a global consensus already actually exists, my apologies in advance).
The introduction part contains an extensive tabulation of requirements for instrumentations in the entire ILC accelerator complex. This is VERY nice. This information might as well stay part of BCD. However, have they gone through reviews by pertinent area groups (or ex-WGs) and have their concurrence?
The fundamental concept of the present ILC control system BC appears to be a 3-tier system architecture where some (or all?) aspects of the service network being supported by ATCA (Advanced Telecom Computing Architecture) hardware. Is this correct correct? If so, what are their implications to the hardware subsystems (magnets, RF, monitors, etc) design, which everyone (ordinary people, that is) should be aware of?
Section 10.4 refers to the potential benefits of, and desire for, the Global Network.However, it is lacking any analysis of cost/technical/operational/managerial implications. Moreover, no systematic discussion has taken place since the “cold” decision in 2004. GDE had better explicitly determine the extent, timing and magnitude of introducing GAN-compatible control systems architecture.
Section 10.5 Machine Protection. Use of (1) a benign pilot bunch and (2) a beam permit system are the two critical ingredients in the MPS context. All area groups should review if their systems are compatible with these prerequisites, if they are to be considered BC. Also, Table 1 has a list of beam shutoff points, which appear reasonable to Toge. Have we all agreed that they should be our BC?
What is the geological model of the control system? Besides the ILC main control center which will be presumably located somewhere near the IR, do we plan on having several local control rooms near, for instance, access entrance halls along the linacs and/or cryoplants, etc? This does not necessarily have to be resolved as part of the BC-stage decisions, but it will have to be towards RDR.
General Amateur Questions from Toge
Control Standard Architecture: Toge did not understand a number of technical terms there. What is “a dual star network model” that appears in 10.1 2/a? Is this a regular control systems terminology? Likewise, what does “a central modular computer cluster” mean? Is it “THE” computer cluster for the central ILC control or are their many such clusters? What does the word “sector” mean (sounds like a certain number of RF stations and cavities associated with them) in the term “sector node processors”?
Timing System: Toge wonders if one main timing control and fiducial generator is to produce reference control signals for both linacs on the electron and positron sides (this is just a curiosity question).
Diagnostic Interlock Layer: Toge wonders if it is correct to take “modules” in this section as DIL control modules. So, for instance, when the Modulator section writes “near 100% system availability”, it is referring to the near perfect availability of the modulator DIL, ont the availability of the entire relevant system including the modulator hardware… correct?
Section 10.7 LLRF: How is the ILC LLRF related to that of Euro-XFEL in terms of system specifications, architecture, implementation, testing and so on?
Section 10.6 Beam-based Feedback Systems: Have people checked the consistency between this section and the I&C requirements in the Introduction?
