Beam Bunch Distribution Mike Lamont 11032008 LHC bunch

Beam Bunch Distribution Mike Lamont 11/03/2008 LHC bunch configuration

Communication n GMT BST DIP pub/sub n Oracle n n ¨ n n 11/03/2008 Advance Queues – JMS – publication JAPC monitoring pub/sub CMW get/set pub/sub LHC bunch configuration 2

Timing - Basic concepts n EVENTS Events arrive asynchronously and can be subscribed to ¨ Each event is a 32 -Bit quantity… ¨ n Type of event 4 -Bits ¨ n Accelerator 4 -Bits ¨ n User, UTC, Telegram-Group-Value TELEGRAMS ¨ ¨ n Event-Code, Telegram-Group … Payload 16 -Bits ¨ n LHC, SPS, CPS, PSB, ADE … Code 8 -Bits ¨ n Timing=CTIM, UTC-Time, Telegram …. Sent out at fixed frequency, 1 Hz in the LHC Snapshot SAFE MACHINE PARAMETERS ¨ 11/03/2008 as events & telegrams LHC bunch configuration 3

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Baudrenghien’s Convention: The 400 MHz RF defines 35640 buckets, spaced by one RF period, and numbered from 1 to 35640 Bucket 1 is the first bucket after the 3 ms long abort gap (defined from bucket 34442 to 35640) Bunches in bucket 1 of the two rings collide in IP 1 11/03/2008 LHC bunch configuration 7

Injection request n BTNI ¨ n n 11/03/2008 Next injection RF Bucket There are 35640 RF buckets around the LHC ring. It is essential that this parameter is established before RF re-synchronization starts between the CPS and the SPS RF systems, namely 450 ms before CPS extraction towards the SPS RNGI ¨ n The LSEQ may request a certain type of beam to be injected, but if the requested value does not correspond to the actual beam type being provided by the injector chain, then the request can not be fulfilled and no injection can take place. BKNI ¨ Next injection Beam Type Next injection Ring This parameter determines the value of the SPS beam destination in the DEST group of the telegram. Various ways to do this are possible. Its an OP decision. BCNT Number of CPS batches LHC bunch configuration 8

Beam Type n Incoming and Circulating Beams n 2*4 telegrams per beam Number of bunches ¨ bunch spacing [units of 25 ns] ¨ bunch intensity [units of 109] ¨ particle type [ 0 – protons, 1 – ions] ¨ n BST ¨ 11/03/2008 Number of bunches, average bunch intensity LHC bunch configuration 9

Bunch Configuration - proposal n n We have 35640 RF buckets Max occupancy ~3000 ¨ short occupied. Buckets. B 1[3000] n ¨ short number. Occupied. Buckets. B 1 n n 72 We will inject maximum of ~300 bunches ¨ short incoming. Destination. Buckets. B 1[300] n ¨ ¨ [1, 11, 21…] short number. Incoming. Bunches. B 1 n 11/03/2008 [1, 11, 21…. ] 288 or see Andy’s suggestion encoding based on PS/SPS spacings etc. LHC bunch configuration 10

Bunch Configuration n Covers all cases four equidistance bunches ¨ off by one bucket collisions ¨ 1, 43, 156… ¨ n Set on database LHC run configuration ¨ published to DIP ¨ publish to JMS – any high level applications ¨ n n Updated preceding injection – incoming Updated post injection – circulating ¨ n assume time constraints for experiment not critical during injection phase Set RF FESA property Circulating: 3564 bit array required at low level ¨ Incoming: 924 bits ¨ To be discussed/decided after this meeting! ¨ 11/03/2008 LHC bunch configuration 11

FBCT n average. Bunch. Intensities ¨ n history. Beam. Intensity ¨ n double/array(337500) --relative timestamps 30 -seconds history of whole beam intensity turn by turn. nb. Averages. Bunch. Intensities ¨ n long/array(2) --absolute timestamp of youngest history data point, seconds, microseconds history. Beam. Intensity. TS ¨ n long/scalar --index in history of the next data point. history. Beam. Intensity. T ¨ n double/array(337500) --30 -seconds history of whole beam intensity turn by turn. history. Beam. Intensity. Next. Index ¨ n -- double/array(3564) --individual bunch intensities averaged over 1 second -- long/scalar --the number of measurements which are going into the averaging. Each measurement covers 227 turns (20 ms) in order to suppress 50 Hz ambient radio noise. nb. Turns. Bunch. Intensities ¨ long/scalar --the number of turns which are going into the averaging. Each measurement covers 227 turns (20 ms) in order to suppress 50 Hz ambient radio noise. Will push average. Bunch. Intensites over DIP 11/03/2008 LHC bunch configuration 12