Wiki source code of Info collection for the BAM

Last modified by sndueste on 2025/02/06 10:58
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sndueste 11.1 1 == Some general stuff: ==
sendels 1.1 2
sndueste 11.2 3 * (% style="color:#000000" %)There are several BAMs in FLASH. Essentially one in the accelerator section  (FL0.DBC2, Previously: 4DBC3) and one close to the respective undulator section (FL1.SFELC and FL2.SEED5).
4 * (% style="color:#000000" %)The BAM measures the arrival time for each single electron bun in the bunch train (for working principle see [[MSK SDiag Projects>>url:https://confluence.desy.de/display/SDiagPublic/MSK+SDiag+Projects||shape="rect" style="color: rgb(0,0,0);"]] or literature listed below)   
sndueste 11.1 5 * The data format of the BAM has been completely altered in the 2022 shutdown
sndueste 11.2 6 * (% style="color:#003366" %)before 2022 BAMs were always saving the arrival time information for each 1µs bucked regardless if there were electrons in the accelerator or not. In addition the arrival times for  FL1 and FL2 were saved in the same parameter ...
7 * (% style="color:#003366" %)THIS is now different. There are new parameters saving only the arrival times for pulses that go to FL1 and to FL2 (in detail: first time slot of the accelerator and second)
8 * (% style="color:#003366" %)(typically) Bigger numbers indicate later arrival time of the electrons
9 * (% style="color:#003366" %)The arrival time should be within -20 ps and +20 ps - otherwise there might be a problem ...
sndueste 10.1 10 * (((
sndueste 11.2 11 (% style="color:#003366" %)The actual time t0 = 0ps is an arbitrary offset which is only changed after setting up the system after, e.g., a maintenance time, and has no relevance.
sndueste 10.1 12 )))
sndueste 11.1 13 * (((
sndueste 11.2 14 (% style="color:#003366" %)What one usually does, after defining/finding time zero in the experiment, is either observe the relative changes for a single bunch during the course of the measurement run compared to the starting point, or (in addition) observe the relative deviation across all bunches within the same bunch train.
sndueste 11.1 15 )))
16 * (((
sndueste 11.2 17 (% style="color:#003366" %)Those deviations and drifts happen usually only in the order of 50fs to 200fs; depending on the machine setup.
sndueste 11.1 18 )))
19 * (((
sndueste 11.2 20 (% style="color:#003366" %)The short-term timing jitter (over several 100 trains) for each individual bunch, i.e. the standard deviation from their mean value, is usually ~~ 20fs.
sndueste 11.1 21 )))
22 * (((
sndueste 11.2 23 (% style="color:#003366" %)The actual measurement resolution of a BAM can be - currently - as good as 3fs, for each bunch in the full train.
sndueste 11.1 24 )))
sndueste 10.1 25
26 == Data structure ==
27
sndueste 11.2 28 * (% style="color:#000000" %)The details about the functionality and the data structure can be found on the page:  (%%)**[[ BAM Data Structure>>https://xwiki.desy.de/xwiki/bin/view/SDiag/How-to%20articles/BAM%20Data%20Structure/||shape="rect"]]**
sndueste 13.1 29 * also see  [[doc:FLASHUSER.Data Acquisition and controls.DAQ and controls overview.Offline data analysis (DAQ).The FLASH HDF5 structure.WebHome]]
sndueste 14.1 30 * an example for the correction of pump-probe delay [[can be found here>>doc:FLASHUSER.Data Acquisition and controls.DAQ and controls overview.Offline data analysis (DAQ).Collection of HDF5 sample data from different beamlines.WebHome]]
sndueste 10.1 31
32 = Publications related to BAM =
sendels 1.1 33
sndueste 10.1 34 === BAM principle ===
sndueste 5.1 35
sndueste 11.2 36 1. (% style="color:#172b4d" %)A. Angelovski, et al.(%%)
37 (% style="text-align:left" %)//Evaluation of the cone-shaped pickup performance for low charge sub-10 fs arrival-time measurements at free electron laser facilities//(%%)
38 (% style="color:#172b4d" %)Phys. Rev. ST Accel. Beams (% style="text-align:left" %)**18**(% style="color:#172b4d" %), 012801 (2015)(%%)
39 [[https:~~/~~/doi.org/10.1103/PhysRevSTAB.18.012801>>url:https://doi.org/10.1103/PhysRevSTAB.18.012801||rel="nofollow" shape="rect" style="text-align: left;"]]
sndueste 5.1 40
sndueste 10.1 41 === Two publications showing how to use the BAM data to improve the time resolution: ===
sndueste 5.1 42
sndueste 11.2 43 1. Evgeny Savelyev, et al, 
sndueste 10.1 44 //Jitter-Correction for IR/UV-XUV Pump-Probe Experiments at the FLASH Free-Electron Laser//,
sndueste 11.1 45 New J. Phys. **19**, 043009 (2017), [[https:~~/~~/doi.org/10.1088/1367-2630/aa652d>>url:https://doi.org/10.1088/1367-2630/aa652d||shape="rect"]]
sndueste 10.1 46 1. (((
47 Dennis Mayer, Fabiano Lever and Markus Gühr,
48 //Data analysis procedures for time-resolved x-ray photoelectron spectroscopy at a SASE free-electron-laser//,
sndueste 11.2 49 J. Phys. B: At. Mol. Opt. Phys. **55**, 054002 (2022); [[https:~~/~~/doi.org/10.1088/1361-6455/ac3c91>>url:https://doi.org/10.1088/1361-6455/ac3c91||shape="rect" style="text-decoration: none;"]]
sndueste 10.1 50 )))
sendels 1.1 51
sndueste 10.1 52 === Publications showing the correlation between the values measured by the BAM and the XUV pulse arrival time ===
cpassow 4.1 53
sndueste 11.2 54 1. (% style="color:#000000" %)//** Description of the FLASH synchronization system**//(%%)
55 (% style="color:#000000" %)S. Schulz, et al.(%%)
56 (% style="text-align:left" %)//Femtosecond all-optical synchronization of an X-ray free-electron laser//(% style="color:#000000" %),(%%)
57 (% style="color:#000000" %)Nature Communications (% style="text-align:left" %)**6**(% style="color:#000000" %), 5938 (2015); (%%)[[http:~~/~~/dx.doi.org/10.1038/ncomms6938>>url:http://dx.doi.org/10.1038/ncomms6938||shape="rect" style="text-decoration: none;text-align: left;"]]
58
59 1. //**Showing a correlation of 11 fs rms between BAM and XUV arrival time**//
60 R. Ivanov, et al to be published 2022  
61
sndueste 10.1 62 1. (((
63 //**Showing a correlation of 20 fs rms between BAM and XUV arrival time**//
64 R. Ivanov, J. Liu, G. Brenner, M. Brachmanski and S. Düsterer,
65 //FLASH free-electron laser single-shot temporal diagnostic: terahertz-field-driven streaking//,
66 Special Issue (PhotonDiag2017),
sndueste 11.2 67 J. Synchrotron Rad.** 25**, 26-31 (2018);[[ https:~~/~~/doi.org/10.1107/S160057751701253X>>url:https://doi.org/10.1107/S160057751701253X||shape="rect" style="text-decoration: none;"]]
sndueste 10.1 68 )))
69 1. (((
70 //**Study of arrival time fluctuations**//
71 Ivette J. Bermúdez Macias, Stefan Düsterer, Rosen Ivanov, Jia Liu, Günter Brenner, Juliane Rönsch-Schulenburg, Marie K. Czwalinna, and Mikhail V. Yurkov,
72 //Study of temporal, spectral, arrival time and energy fluctuations of SASE FEL pulses//,
sndueste 11.2 73 Optics Express 29, 10491-10508 (2021); [[https:~~/~~/doi.org/10.1364/OE.419977>>url:https://doi.org/10.1364/OE.419977||shape="rect" style="text-decoration: none;"]]
sndueste 10.1 74 )))
cpassow 4.1 75
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