Injection_BunchPattern

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					Numerology (P. Baudrenghien)
For each ring:

  Convention 1: The 400 MHz RF defines 35640
  buckets, spaced by one RF period, and numbered
  from 1 to 35640
  Convention 2: Bucket 1 is the first bucket after the
  3 ms long abort gap (defined from bucket 34442 to
  35640)

  For 25 ns operation the bunches will occupy buckets 1,
  11, 21 etc. with gaps occurring every PS or SPS kicker
  gap. For 43 bunch operation the bunches will occupy
  buckets 1, 811, 1621, etc. (see LHC-OP-ES-0003 rev
  1.0 for the different schemes).
                 LHC filling schemes




Why t3 and t4?
When should we use one or the other?
      Injection Bunch config

    Injection scheme
    composed
    of injection requests



Injection Scheme
Scheme Name
n
          Injection Scheme Entry              Bunch pattern
          Injection Order
          Next Injection Delay


n         n                               1     n                            1
Injection Request                  Injection Bunch configuration   Bunch pattern
Request name                                                       Pattern name
Next injection ring                                                Description
                                   Configuration name
Next injection beam type                                           Number of PS batches
                                   First Bucket number             Number of bunches per PS
Next injection bunch Int
Next injection particle type                                       batch
Is active                                                          Total number of bunches
                                                                   Bunch spacing
                        Next injection
• To inject a beam into LHC :
   – Next injection Ring
   – Next injection RF bucket (the first bucket filled by the injection)
   – Number of PS batches
   -------------------------------------
   – Next Injection Beam Type : divided into 4 groups in the telegram
       •   NIBNCH : number of bunches
       •   NIBSP : bunch spacing (ns)
       •   NIBIN : bunch intensity (*10E9)
       •   NIPTY : particle type (0=protons, 1=ions)
    Should we add this field into the injection request sent to the CBCM?
        These telegrams groups will be set together with ring bucket and number of
         batches by the CBCM (No need to set it from the application)
        These groups won’t be editable (i.e. sequencer can’t change it)

• OP has to check that the beam in the injector corresponds to what is
  requested
Replaced by
NIBNCH
NIBSP
NIBIN
NIPTY
              Next Injection
• Do we have to publish extra information?
  – I.e. the injection sequencer set a RF FESA
    class with the next filled buckets
• Active injection request
  – The injection that is being executed (from the
    request to the CBCM to the injection quality
    check validation)
  – Accessible through LSA client API
• Is it needed to know before we start
  injecting what is the expected bunch
  configuration after the injection process?
            Circulating bunch config
  • Information about circulating bunch configuration exists :
      – In a table in LSA DB
CirculatingBunchConfiguration
-beam number                       1-2
-bunch number                      1 to 2808 (number of bunches for 25ns nominal scheme)
-bucket number                     1 to 35640 : total number of buckets

          • An array of filled buckets is published from this table.
            (ACCCON_SYS.ANYDATA_QUEUE/LHC_CIRC_BUNCH_CONF_B1)
          • Extra information needed to be published :
                 – The SPS batch number for each bunch
                 – The bunch intensity
    – In the telegram groups
        • As for injection beam type, the circulating beam type groups (BTC1
          and BTC2) will be replaced by 4 groups per beam
             –   C1BNCH : number of bunches
             –   C1BSP : bunch spacing (ns)
             –   C1BIN : bunch intensity (*10E9)
             –   C1PTY : particle type (0=protons, 1=ions)
Replaced by
C1BNCH
C1BSP
C1BIN
C1PTY

Replaced by
C2BNCH
C2BSP
C2BIN
C2PTY
 Circulating bunch configuration
• Telegram and database have to be
  updated after each injection and after a
  beam dump
  – Who, how?
  – Should it be updated as well if a part of the
    beam is lost?
 Depends if it represents
  – What we have in the LHC
  – Or what we aim to have in the LHC

				
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posted:4/1/2011
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