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Scenario-Schottky_03

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Scenario-Schottky_03 Powered By Docstoc
					Scenario ID   138 v3
Author        Jean Slaughter with consultation from Andreas Jansson, Ralph
              Pasquinelli, Paul Lebrun
Date          8-June-2005
Reviewers     Elvin Harms.
Reviewed
Approved
Goal          Commission Schottky detector
Level         High level
Actors        Fermilab Physicist (Andreas) and Engineer (Ralph) at FNAL,
              Fermilab contact person at CERN (Peter), CERN Physicist
              (Mike), CERN operators. Andreas and Ralph built the device.
              Mike will be one of the people using it later to help understand
              the machine.
Trigger       First beam has circulated in one ring of the LHC and tune up is in
              progress. Ralph and Andreas want to see signals and time it in.
              An access is scheduled in two days and they want to know if
              they need to arrange for tunnel work. Mike wants to be involved
              so he understands the operation.
Narrative        1. Assumptions. The Schottky detector and VME Front end
                    electronics in the tunnel have been debugged as much as
                    possible without beam using injected signals. The VME
                    front end electronics is not accessible without an access.
                    There is only a very rudimentary high level application but
                    it allows the operator to set most parameters and display
                    the FFTs. The relative delays cannot be adjusted via the
                    application. Scope traces, FFTs and numerous other
                    parameters such as voltages and temperatures are
                    available remotely and values can be datalogged. VME
                    code, raw data (before the FFT) and some parameters
                    can only be accessed via direct connection to the front
                    end. The LHC@FNAL console has been set up and is
                    allowed to run the application and view datalogged
                    parameters. However, direct access to the front end VME
                    is only allowed at CERN. The Schottky is not yet
                    commissioned, so is not yet in routine use in the CCC
                 2. CERN weekly planning meeting. Ralph, Andreas and
                    Mike have submitted a study plan for their parasitic study
                to the appropriate person. It gives necessary beam
                conditions. The study is approved, and will be scheduled
                as appropriate during the daily planning/scheduling
                meetings.
             3. Day 1 CERN daily meeting. The study is approved for the
                evening shift, but is to be totally parasitic. The
                Fermilab@LHC person (Peter) notifies Ralph and
                Andreas and then goes home to sleep as he and Mike will
                be on duty with a machine at CERN that can access the
                front end directly.
             4. 8:00 CST. Ralph and Andreas arrive in LHC@FNAL
                center. Peter and Mike log into the front end in an office,
                as the CCC stations are all occupied. Ralph and Andreas
                set themselves up with displays that allow them to monitor
                beam conditions, read the logbook, and start the Schottky
                application and monitor scope traces. Using the
                application they can only modify quantities which do not
                affect the beam. They are in cell phone and Instant
                Messenger(IM) contact with Peter and Mike. They are
                also in IM contact with a CERN operator.
             5. Throughout the shift there are erratic periods of beam.
                Andreas monitors the beam conditions, while Ralph talks
                with Peter and Mike who are actually adjusting the timing.
                Ralph is watching the displays. Suddenly all signals stop.
                Ralph checks all the monitoring parameters and sees that
                a power supply is malfunctioning. Ralph makes an entry
                in the CERN logbook about what has happened.
             6. Next morning. A report is made in the daily meeting by
                Peter. He passes on a formal request to be added to the
                list for the next access.
             7. Access shift. An access is made, and the power supply is
                replaced. During the access, Ralph and Andreas monitor
                while Peter and Mike run the injected signal diagnostic
                from their laptop in the tunnel. Andreas notices that the
                signal doesn’t look quite right. He asks Peter to double
                check the voltage for the power supply. In fact, one of the
                power supply voltages is low. Peter pulls up a drawing on
                the laptop, while Ralph tells him where to look for the
                adjustment screw. Peter readjusts the voltage, reruns the
                test, and Andreas reports everything is ok.
             8. Several days later, there is another opportunity for
                studies, and the process is repeated.
Exceptions
Comments   The success of this scenario depends on sufficient bandwidth for
           scope pictures to be viewed and the results of the adjustments
           seen in real time.
           The ability to directly log into to the VME from the LNC@FNAL
           center would make this much more efficient. However the
           presence of someone to make an access is critical, and being
           able to contact experts while on access is also needed.

				
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posted:11/23/2011
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