Bunch-to-Bucket Transfer System

This work package was frozen from mid 2017 to mid 2019

The purpose of the Bunch-to-Bucket (B2B) transfer system is to transfer ion beams over the whole range of isotopes from one ring to another at GSI and FAIR. It employs the so-called phase-shift or frequency beating methods to achieve a phase match between bunch and bucket to better than 1 degree. The Bunch-to-Bucket (B2B) Transfer System is essential and indispensable for the FAIR accelerator chain. Without, no beam can be transferred from SIS18 to SIS100 and to follow-up machines. The B2B system is realized by the General Machine Timing (GMT) system and the Low-Level RF (LLRF) system. The B2B system is closely linked to other systems like kicker control and electronics as well as the machine protection system.


The aim of this web is to provide an overview on the Bunch-to-Bucket transfer system and its relationship to other systems. Moreover, it is the central point for documentation. Please note, that the B2B transfer system is still under development.




  • 28-Feb-2024 til 12-Mar-2024
    • check differential signal at ESR extraction (kicker module 1)
    • signal is not at all clean due to the many reflections in long cables to various locations, length of kick pulse can not measured reliably
    • decision: don't use the capacitive differential signal at ESR but the 'direct' signal that has amplitudes up to 60V, depending on the kick angle
    • new comparator box by Experiment Electronics (EEL)
    • comparator box for ESR extraction replaced by new one
    • it works
    • 2024-mar-06_transfer-monitor.jpg
      Figure: green: measured offset of rising edge and length of magnet probe signal [ns]; blue: measured 'kick offset'; red: the length of the magnet probe signal at CRYRING can not be determined precisely
    • 2024-mar-06_comparatorESR.jpg
  • 03-Nov-2023
    • test of comparator at SIS18 extraction kicker (click)
  • 23-Oct-2023
    • new comparator installed at ESR extraction
  • 22-Oct-2023
    • deployed new version (v00.07.00)
      • firmware, data supply: no changes
      • acquisition, analysis, UI: cleanup
  • 15-Oct-2023
    • during a dry run, the interoperability of the b2b system with the h=1 group DDS systems was tested successfully
    • no kicker operation during the entire dry run
  • 06-Oct-2023
    • deployed new version (v00.06.01)
      • stability improvements
      • White-Rabbit jitter check
      • added measurement of frequency of h=1 group DDS for slow extractions
      • added measurement of frequency of h=1 group DDS at injection of storage rings
      • default units in 'Monitor' changed from nanoseconds to degree
      • ...
  • Sept-2023
    • new comparators installed at SIS18 (extraction) and ESR (injection)
  • 31-Aug-2023
    • extraction kicker at CRYRING tested; two issues at kicker itself detected; (see here)
  • 12-Jul-2023
    • kicker test: new comparator for injection kicker probe signal at CRYRING successfully tested
  • 06-Jul-2023
    • new comparator for injection kicker probe signal at CRYRING installed
  • 22-Jun-2023
    • new comparator for extraction kicker probe signal at CRYRING successfully tested (see here)
    • comparator_cryring2.JPG
      Figure: New comparator (white, transparent box) mounted at 1U server in kicker rack.
  • 05-May-2023 til 09-Jun-2023:
    • successful operation in 'Device Testblock' and 'Dryrun'
    • details can be found here
    • b2b-sis18-esr-b2b-phase-difference_zoom.png
      Figure: bunch-2-bucket transfer from SIS18 to ESR; x-axis: measured phase difference between SIS18 and ESR h=1 DDS (the ParamModi set-value of 597.318 ns has been subtracted); y-axis: histogram data of 8833 transfers; the beating time between the two h=1 signals is about 8.4 ms.
  • 23-May-2023:
    • deployment of new b2b version to PRO environment
  • 17-May-2023:
    • deployment of new b2b version to INT environment
  • 15-May-2023:
    • the so-called sub-nanosecond fit has been deployed
      • increase precision of a single phase measurement to typically 100 ps
      • increase precision of phase-matching for bunch-2-bucket transfer to typically 200-300 ps for long beating times exceeding 1 ms
      • significance of calculated/transmitted/displayed numbers has been extended to 1ps
  • 12-May-2023:
    • new comparator type developed by 'Experiment Electronics'
      • same electronics ...
      • ... but comparator level can be set remotely (via USB)
      • hardware-doc.png
  • 29-Jun-2022:
    • esr-stacking.png
      Figure: stacking of beam in ESR (multiple injections from SIS18) with the bunch-2-bucket transfer system
  • 07-Jun-2022:
    • b2b_esr-yr.png
  • 02-Jun-2022:
    • dedicated machine experiment SIS18 -> ESR
    • b2b-_sis-esr.png
      Figure: true bunch-to-bucket transfer SIS (h=1) -> ESR (h=3); only one bucket gets filled
  • 01-Jun-2022:
    • more than four months of flawless operation ...
    • synchronization of ion bunch with PHELIX laser in cave HHT with 1 nanosecond precision
    • transfer from SIS18 to ESR as 'coasting beam'
    • fast extraction from ESR to HITRAP
    • transfer from ESR to CRYRING as 'coasting beam'
    • fast extraction from CRYRING
  • 22-Apr-2002:
    • first steps towards sub-ns precision for phase measurement (click)
  • 28-Jan-2022:
    • beam commissioning starts
    • first fast extraction from SIS18 in 2022 (using the b2b transfer system of course)
  • 17-21-Jan-2022, 'dry-run':
    • first operation of both CRYRING kickers with the b2b system
    • final model integration (CRYRING) and new LSA version deployed
    • timing of all extraction and injection kickers at GSI controlled by the b2b system
    • first successful operation of the b2b transfer in the entire facility demonstrated using coupled patterns of a chain SIS18 -> ESR -> CRYRING -> extraction!
    • b2b-sis-esr-yr.png
      Figure: operation of all kickers of all ring machines SIS18 -> ESR -> CRYRING
  • 12-Jan-2022:
    • installation of electronics at CRYRING injection and extraction kicker
  • 25-Nov-2021:
    • successful triggering of SIS18 and ESR kickers
    • demonstration of booster mode
    • b2b_booster_2021-11-25.png
      Figure: booster mode on-line view (blue box) visualized by the B2B Monitor app. Shown are time of extraction (column 2), extraction machine, sequence ID and revolution frequency (columns 3,4,5), set-value of kicker trigger (column 6) and measured values of kicker trigger, delay of kicker electronics and delay of rising edge of kicker magnet probe signal (columns 7,8,9). Shown are also four other patterns executed in parallel; bunch-to-coasting beam SIS18->ESR (line 1), two patterns in ESR towards CRYRING beam-line and HITRAP (line 6,7) and a pattern in CRYRING with extraction (line 8). The ERROR at the CRYRING kicker indicates not yet installed componentes of the b2b system. The UNKNOWN values of the ESR kicker magnet probe delay require further commissioning.
  • 22-Nov-2021:
    • for the first time, the startup of the facility after a shutdown uses the bunch-to-bucket transfer system as the default transfer and extraction system
  • 18-Nov-2021:
    • phase measurement of DDS signals successfully tested at SIS18, ESR, CRYRING
  • 16-Nov-2021:
    • FESA classes for Central Bunch-2-bucket Unit (CBU) available and deployed to the PRO environment
    • two new analog signal processing units installed at SIS18 and ESR RF rooms
  • 10-Nov-2021:
    • CBU for CRYRING installed in RRF electronics room
    • 10 new fast and precise analog signal processing units delivered by the department of Experiment Electronics (EEL)
    • two units installed in SIS18 and ESR kicker rooms
Figure: Left: New comparators units delivered. Right: Unit mounted at a server of 1U height.
  • 15-Okt-2021:
    • integration system: 1st successfull integration of B2B in the full control system stack including ParamModi and LSA for SIS18 -> ESR
  • 24-Sep-2021:
    • FESA classes for Central Bunch-2-bucket Unit (CBU) available and deployed to the INT environment
  • 9-Sep-2021:
    • production system ported to timing release fallout 6.1.2
    • test setup based on fallout 6.1.2 installed at INT (transfers starting at SIS18 only)
    • DIM name server moved from office PC to ACC VM (rocky 8)
    • nomen for SIS18, ESR and CRYRING fixed
  • 13-Jul-2021:
    • first prototype of new signal conditioning unit tested with probe signal at SIS18 extraction kicker
  • 17-May-2021:
    • first bunch-to-bucket transfer SIS18 (h=2) -> ESR (h=1)
    • 2021-05-17_18-34-49_tcl1032_fct-ring_trunc.png
Figure: Signal from FCT GE02DT1FP: Bunch from SIS18 captured in an ESR bucket. x-axis: bunch time [us] relative to h=1 (1.975 MHz), y-axis: time [ms] after acquisition start from bottom to top. The bunch is captured ~0.25 ms after acquisition start. Shown are data of ~ 3 ms after aquisition start. Data acqusition, processing and image are done by our colleagues from beam instrumentation.
  • 13-May-2021:
    • already two days of continous beam operation serving two distinct experiments in parallel
    • bunch-to-coasting-beam SIS18 -> ESR
    • fast extraction to cave HHT (experiment: synchronization of petawatt laser PHELIX with extracted ion bunch)
  • 11-May-2021:
    • first beam with the bunch-to-bucket system
    • 'bunch-to-coasting-beam' SIS18 -> ESR
    • bunch2coasting_2021-05-11.png
Figure: Bunches from the synchrotron SIS18 (magenta) are transferred into the storage ring ESR (orange, red)
  • 13-Apr-2021:
    • 'dry test' with SIS18 extraction kicker (just to confirm things work)
    • test with new Group DDS at SIS18
  • February 2021:
    • dry operation in parallel to beam time
    • see results
  • 15-Jan-2021: 'dry run'
    • bunch-2-bucket SIS18 -> ESR
    • comfortable command line interfaces for control and monitoring
    • see results
  • 05-Dec-2020: new page on B2B lite, setup, results
  • 27-Nov-2020: 'dry run'
    • phase matched extraction from SIS18
    • 'bunch to coasting dry beam ' transfer from SIS18 to ESR
    • see results
  • 26-Nov-2020: phase-matched extraction from ESR (with 'dry beam')
  • 23-Nov-2020: for the first time, the B2B system triggers the ESR kicker successfully!
  • 18-Nov-2020: for the first time, the B2B system triggers the SIS18 extraction kicker successfully!
  • 23-Dec-2019: proof-of-principle phase matching (using frequency beats) in RF supply room, see here
  • 12-Jun-2019: proof-of-principle phase matching (using frequency beats) on office table, see here


BunchBucket Web Utilities

-- DietrichBeck - 12 Mar 2024
I Attachment Action Size Date Who Comment
2021-05-17_18-34-49_tcl1032_fct-ring_trunc.pngpng 2021-05-17_18-34-49_tcl1032_fct-ring_trunc.png manage 59 K 21 May 2021 - 08:13 DietrichBeck SIS18 -> ESR, first bunch to bucket
2024-mar-06_comparatorESR.jpgjpg 2024-mar-06_comparatorESR.jpg manage 2 MB 12 Mar 2024 - 14:09 DietrichBeck comparator hardware for ESR
2024-mar-06_transfer-monitor.jpgjpg 2024-mar-06_transfer-monitor.jpg manage 84 K 12 Mar 2024 - 14:18 DietrichBeck b2b monitor
b2b-_sis-esr.pngpng b2b-_sis-esr.png manage 61 K 08 Jun 2022 - 14:44 DietrichBeck bunch to bucket transfer sis->esr
b2b-sis-esr-yr.pngpng b2b-sis-esr-yr.png manage 52 K 26 Jan 2022 - 15:00 DietrichBeck SIS18 -> ESR -> YR ->Extraction
b2b-sis18-esr-b2b-phase-difference_zoom.pngpng b2b-sis18-esr-b2b-phase-difference_zoom.png manage 53 K 14 Jun 2023 - 14:26 DietrichBeck measured phase difference SIS18 - ESR
b2b_booster_2021-11-25.pngpng b2b_booster_2021-11-25.png manage 64 K 25 Nov 2021 - 19:16 DietrichBeck first booster mode operation using the b2b system
b2b_esr-yr.pngpng b2b_esr-yr.png manage 758 K 08 Jun 2022 - 14:48 DietrichBeck b2b ESR->YR
b2b_logo.pngpng b2b_logo.png manage 22 K 17 Oct 2020 - 11:03 DietrichBeck first unofficial logo with transparent background
bunch2coasting_2021-05-11.pngpng bunch2coasting_2021-05-11.png manage 301 K 11 May 2021 - 19:40 DietrichBeck SIS18 -> ESR, bunch to coasting beam
comparatorDelivered.JPGJPG comparatorDelivered.JPG manage 866 K 10 Nov 2021 - 10:56 DietrichBeck comparator delivery
comparator_cryring2.JPGJPG comparator_cryring2.JPG manage 934 K 23 Jun 2023 - 08:20 DietrichBeck comparator yr extraction kicker
esr-stacking.pngpng esr-stacking.png manage 66 K 01 Jul 2022 - 15:04 DietrichBeck stacking in ESR
hardware-doc.pngpng hardware-doc.png manage 794 K 20 Jun 2023 - 14:17 DietrichBeck  
Topic revision: r56 - 12 Mar 2024, DietrichBeck
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