1 Digital BPM Systems for Hadron Accelerators

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1 Digital BPM Systems for Hadron Accelerators Proton Synchrotron 26 GeV 200 m diameter 40 ES BPMs Built in 1959 Booster TT70 East hall CB Trajectory measurement: System architecture Inputs Principles of operation Measurement examples TT2 Y Linac II LEIR North hall South hall 1 Digital BPM Systems for Hadron Accelerators

2 System architecture For one PU station: Bus or network Σ X Y 3 x ADC 14 bits 125MS/s 3 x 14 FPGA data address Memory 1GB SCY CAL START CAL STOP INJ H CHANGE ECY 10MHz Frev ADCs: LTC2255, 14 bit, 125MS/s FPGA: Xilinx Virtex-4 Memory: 256MB/PU Data is streamed into a circular buffer. Persistence: A few seconds 2 Digital BPM Systems for Hadron Accelerators

3 System architecture System controller (Basically a Linux PC) Network Network switch VME/FESA timing/gain ctrl Module controller Timing patch PU processing engines 14 PU Processing Engines Treating 3 PUs each 3 half-width cpci crates One system controller The cpci crate processors are connected to the system controller using Gigabit Ethernet. The system controller connects to the accelerator network using a 2nd network interface. A VME crate for timing, pre-amp control and a FESA server 8 slot cpci 3 Digital BPM Systems for Hadron Accelerators

4 TMS photo cpci crates Timing cpci crates 4 Digital BPM Systems for Hadron Accelerators

5 Position measurement principle Position of each bunch is measured individually Integration over the length of one bunch Base Line Restoration is needed because the BPMs have no DC response PU Gate BLR BLR BLR 5 Digital BPM Systems for Hadron Accelerators Gate

6 Data paths Σ, X,Y integrals bunch rate 25 Averagers 1ms rate Memory 256MB Trajectories are the main object of the system Orbits are recorded by accumulating averages at 1ms intervals There is an averager for each bunch One channel averages over all bunches MRP requires additional post-processing Most of the memory is used for trajectory data (0xfe00000 bytes). Averaging tables are of size Digital BPM Systems for Hadron Accelerators

7 Synchronization PU Σ F rev F inj NCO Phase Table MSB LO1 LO2 Gate BLR Phase error Start Cal CalStrt CalS PU azimuth State Regulator INJ CalStp Wait PU Σ F ref INJ Gate H8 INJ BLR HCH LO one revolution H16 7 Digital BPM Systems for Hadron Accelerators

8 Phase Table Editor Purpose: Define state sequence Define harmonic values Generate Gate, BLR and LO There is a state table file for each beam type The system loads the right one according to the PLS telegram just before each cycle start 8 Digital BPM Systems for Hadron Accelerators

9 Some considerations... The aggregate front-end data rate is 30 GB/s (120 channels x 125MS/s x 2 bytes). After data reduction: 3GB/s (40 BPMs x 20 bunches x 8 bytes x 477 khz). The system acquires more data than you can hope to get out of it. The TMS can serve multiple simultaneous independent clients. It can deliver up to about 500k points/cycle. That's about 25ms of trajectory, or instantaneous positions at a given PU over a full acceleration cycle of 1.2s. Intervening software layers and network bottlenecks may well prevent you from exploiting that. 9 Digital BPM Systems for Hadron Accelerators

10 Software architecture tmspuserver CERN Control room application tmspuserver tmsserver FESA Expert user application tmspuserver TMS specific diagnostic clients 10 Digital BPM Systems for Hadron Accelerators

11 Expert interface using FESA 11 Digital BPM Systems for Hadron Accelerators

12 Work at GSI, for SIS18 Hardware platform: I-tech's Libera Digitizes individual plate signals. Beam-synchronous timing via threshold crossing detection. 14b 125MS/s 12 (Contributed by GSI) Digital BPM Systems for Hadron Accelerators

13 Data Acquisition and Analysis for SIS18 BPM The position of each individual bunch is transferred to the server The readout via FESA (CERN), developed in cooperation with COSYLAB Status: Nearly finished incl. GUI First test in Feb. 09 Features: Data rate: up to 600 MB/s (50MB/s per BPM) On-the-fly calculations Evaluation tools for tune (see poster), closed orbit, trajectories 13 (Contributed by GSI) Digital BPM Systems for Hadron Accelerators

14 P+ beam, injection turns [mm] section 14 Digital BPM Systems for Hadron Accelerators

15 P +, injection oscillations & injection bump collapse mm FFT of the first 400 turns [mm] tune x turn 15 Digital BPM Systems for Hadron Accelerators

16 Side-by-side comparison of CODD and TMS Note: 25 turns superimposed One of two 5e12ppb P + bunches, 11ms after injection 16 Digital BPM Systems for Hadron Accelerators

17 P +, position at PU43, full cycle mm turns (These data are low_pass filtered to reduce noise) 17 Digital BPM Systems for Hadron Accelerators

18 128k revolutions mm 20k mm 4k SFTPRO γ-transition crossing seen at PU33 18 Digital BPM Systems for Hadron Accelerators turns

19 Ejection: Sum signal on PU15 starting at 838ms AU Note: Extraction over 5-turns turns 19 Digital BPM Systems for Hadron Accelerators

20 Conclusions The old PS trajectory system (CODD): Two-turn trajectories only On one selected bunch 5ms dead time The new PS trajectory measurement system (TMS): Thousands-of-turns trajectories Orbits (trades time resolution for position resolution) Multi-bunch acquisitions For both systems: Raw resolution: 0.3mm We acknowledge the support of the European Community-Research Infrastructure Action under the FP6 Structuring the European Research Area programme (DIRAC secondary beams, contract number ). 20 Digital BPM Systems for Hadron Accelerators