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Accelerator Science and Technology Seminar

This event takes place in the following cycle:

Tuesdays, 14:00 - 15:00 h,  every other week
(even calendar weeks - except during the summer holidays)


  • Language: English
  • Duration: 30-minutes, followed by a discussion (official end is 3:00 p.m.)
  • For now, this seminar will only be held online. Please contact Daniel Romeo for a Zoom link.

Seminar Program 2021

Date Presenter Title OU
April 20th Benat Alberdi Esuain "Prospects of high-brilliance beams from the SRF photo-injector for UED experiments" BE-AHBB (HZB)
May 4th Gregor Schiwietz "Design and commissioning of a new optical diagnostics plattform at BESSY II" BE-IA-AOT (HZB)

May 18th

Georgios Kourkafas

"FLASH proton irradiation at HZB" BE-APT (HZB)
June 1st A̶d̶o̶l̶f̶o̶ ̶V̶e̶l̶e̶z̶ "̶S̶t̶a̶t̶u̶s̶ ̶o̶f̶ ̶t̶h̶e̶ ̶V̶S̶R̶ ̶D̶e̶m̶o̶ ̶p̶r̶o̶j̶e̶c̶t̶"̶ BE-IAS (HZB)
June 15th Ji Li "Review of the Robinson Wiggler study for MLS" BE-SRBP (HZB)
Aug. 10th David Meier Artificial Intelligence for the measurement based reconstruction of the complete SRF Gun module setup @ SeaLab University of Kassel
Aug. 24th Adolfo Velez "Status of the VSR Demo project" BE-IAS (HZB)
Sept. 7th Riccardo Bartolini "PETRA IV - Status, Design, Challenges" DESY M
Sept. 21st Joshua Dilly Increasing efficiency and stability of LHC / HighLumi LHC operation
by corrections of high-order nonlinearities
Oct. 5th Axel Neumann Status of the Sealab facility at HZB, a new perspective for bERLinPro? BE-IAS (HZB)
Oct. 19th Andrea Santamaria Garcia Machine Learning Activities at KIT for Accelerators KIT
Nov. 2nd Dr. Seunghwan Shin tbd Pohang Accelerator Laboratory
Nov. 16th Frank Schmidt Non-Linear Analysis and Simulation Campaigns in the LHC Era CERN
Nov. 30th Irma Shmidt Vibration studies at BESSY II - from ground to magnets to beam (Report Master Thesis) BE-IA-ARD (HZB)
Dec. 14th Markus Ries TRIBs with 1.75 GHz beating - an end game idea for BESSY II BE-IA-SRBP (HZB)



20. 4. 2021 - Beñat Alberdi

Prospects of ultra-short bunches with low emittance from the SRF photoinjector

Ultrafast Electron Diffraction (UED) is a technique used to observe dynamical changes in the structure of materials. It is based on a pump-probe scheme: a laser pulse excites the target structure and a subsequent electron bunch scatters in the sample producing a diffraction pattern. The time resolution of UED experiments is governed by the electron bunch length and the time of flight jitter, while the spatial resolution is inversely proportional to the transverse emittances. Hence, high brilliance electron beams are needed in order to provide high temporal and spatial resolution at the same time. The SRF Photoinjector offers unique possibilities to perform UED experiments since the original design is flexible enough to fulfill the strict beam requirements with few changes to the beamline. Two phases are foreseen to achieve time resolved UED: the first phase is a proof of concept experiment with a static target to show that it is possible to achieve the required beam parameters, while the objective of the second phase will be to implement the time-resolved pump-probe scheme. Phase 1 is actually under development and is the main focus of this talk. In order to accomplish the high brilliance beam, the longitudinal phase space of the bunch is linearized at the target position by using three L-band booster cavities. On the other hand, the desired transverse phase space parameters are achieved by the use of an aperture and magnets. In summary, we discuss the basic requirements for such experiment, the ongoing work for the first phase and the outlook of the UED project in HZB

4. 5. 2021 - Prof. Dr. Gregor Schiwietz


"Design and commissioning of a new optical diagnostics plattform at BESSY II"



In sector L12, three beamlines are dedicated to bunch-selective non-destructive electron-beam diagnostics. These beamlines include transverse and longitudinal beam characterization with extremely good time and position resolution as well as the currently most effective 2-dimensional system for time vs. one of the transverse directions.

One beamline (Sector12-Dip2.1) will be placed inside the electron ring tunnel about 2 m above the ring plane. This beamline is intended exclusively for THz intensity measurements and simple spectral THz investigations of short pulses and short-time fluctuations (trigger-free analysis).

A second beamline (Sector12-Dip1.2) for transverse beam characterization is nearly completed. Since the main components are already installed, commissioning started a few weeks ago. The main application will be bunch-selective interferometry with an ultrafast intensified CCD camera system (ICCD) and the first results are promising. Later, our beam-halo monitor will be re-installed on the same optical table.

A third beamline (Sector12-Dip1.1) for longitudinal beam studies is in full operation and the main experimental instrument is an ultrafast synchroscan streak camera (as far as we know, with the highest repetition rate of
1 kHz in the world). For time-integrated acquisitions, the time resolution of this combination of optimized new beamline, trigger, and streak camera is improved by a factor of 3 to 5, and the photon yield is improved by a factor of about 3000 compared to the previous
(standard) system at BESSY II. Some examples of advanced 2D beam analysis (x vs. t or y vs. t) with this system are given during the talk.

18. 5. 2021 - Georgios Kourkafas


"FLASH proton irradiation at HZB"


The HZB Cyclotron provides 70 MeV protons for the radiation therapy of eye tumors in collaboration with the Charité hospital. More than 4000 patients have been treated so far with a 97% tumor control using conventional dose rates (0.25 Gy/s, 60 s). Recent studies indicate that ultra-high dose rates known as FLASH irradiation (>40 Gy/s, <0.5 s) can reduce the side effects, while shortening the treatment time. Adjustments and additions in the beamline, dosimetric studies, and the development of a fast data acquisition and control system have enabled the HZB Cyclotron to cover a wide range of the FLASH regime and accommodate in vivo and in vitro experiments, towards a future clinical application.

15. 6. 2021 - Dr. Ji Li


"Review of the Robinson Wiggler study for MLS"


A Robinson wiggler was planned to be installed in the storage ring of the MLS, aiming for bunch lengthening by manipulating the damping partition numbers. As a strong focusing device in horizontal and vertical plain, the Robinson wiggler changes the linear lattice significantly. In addition, its impact on nonlinear beam dynamics is not negligible. The model of the Robinson wiggler in linear lattice is introduced in this talk. Correspondingly, the symplectic tracking methods for the Robinson wiggler are presented in detail, which are crucial in nonlinear beam dynamics simulations.

15. 6. 2021 - David Meier


"Artificial Intelligence for the measurement based reconstruction of the complete SRF Gun module setup @ SeaLab"



An SRF Gun module has several parameters to be set up and optimized for optimal beam properties during commissioning. This process is usually very time-consuming and tedious.

To overcome this, we can use knowledge extracted by already existing simulations. First, we create a surrogate model using a dataset generated using the simulation. This surrogate replaces the slow simulation. Next, we find the "offsets" – the differences of parameters and screen positioning between simulation and the real machine. The last step is to optimize the beam properties using several global optimization strategies. It turns out that the use of Reinforcement Learning is beneficial in several regards in solving this problem.

24. 8. 2021 - Prof. Dr. Adolfo Velez Saiz


"Status of the VSR Demo project"



Bunch-length manipulation in modern storage rings light sources is mandatory and CW SRF provides the required high voltage in a compact system to reach this goal. VSR Demo seeks to develop and demonstrate the required SRF technology to achieve this by means of “off-line” testing at HZB SUPRALAB facilities. The current status and achievements will be presented in this talk.

7. 9. 2021 - Riccardo Bartolini


"PETRA IV - Status, Design, Challenges"



PETRA IV - Information on status, design and challenges.

21. 9. 2021 - Joschua Dilly


"Increasing efficiency and stability of LHC / HighLumi LHC operation
by corrections of high-order nonlinearities"



The Large Hadron Collider (LHC) at CERN has reached unprecedented energies at very high hadron-beam intensities, presenting novel challenges for machine protection. These and the requirement for well controlled luminosity at the experiments (ATLAS, CMS) are putting tight constraints on the accelerator optics, necessitating the correction of magnetic field errors up to high orders. With the upcoming High Luminosity upgrade of the LHC (HL-LHC) effects even from decapole and dodecapole field orders are foreseen to be detrimental to beam stability and lifetime.

Joschua Dilly is currently conducting his PhD studies at the optics measurements and corrections (OMC) team at CERN and will give an introduction into the topic of accelerator optics with focus on the measurements of linear and non-linear errors in the machine and how they have been mitigated to guarantee successful runs of the LHC, as well as the efforts taken to anticipate and counteract their influence in the HL-LHC.

5. 10. 2021 - Axel Neumann


Status of the Sealab facility at HZB, a new perspective for bERLinPro?



Since end of the year 2020 the energy recovery project bERLinPro is officially completed. But what is the status of this facility, the next scientific goals in the framework of accelerator physics at HZB, what are the perspectives? To reflect the continuation of this endeavor and the eventually broaden application of this machine from high current SRF based energy recovery concept to an ultrafast electron diffraction facility producing shortest electron pulses, the facility is now named Sealab, Srf Electron Accelertor Laboratory.

In this talk, an overview of the status of the machine, the coming set up and commissioning steps with an outlook to midterm and future applications will be given.

19. 10. 2021 - Andrea Santamaria Garcia


Machine Learning Activities at KIT for Accelerators



The Institute for Beam Physics and Technology (IBPT) at the Karlsruhe Institute of Technology (KIT) hosts two research accelerator facilities, KARA and FLUTE, that serve as platforms for the development and testing of new beam acceleration technologies and new cutting-edge accelerator concepts, including Machine Learning (ML) methods. In this talk I will present four ML activities in accelerator physics carried out at KIT:
- Real-Time Control of the Micro-Bunching Instability with Reinforcement Learning
- Bayesian Optimization of the Injection Efficiency
- Machine Learning Towards Autonomous Accelerators: Control of the Bunch Profile with Reinforcement Learning - Anomaly Detection in BPM systems

2. 11. 2021 - Dr. Seunghwan Shin





16. 11. 2021 - Frank Schmidt


Non-Linear Analysis and Simulation Campaigns in the LHC Era



Linear and Non-linear analysis is discussed for the LHC and its pre-accelerators. Emphasis is given to the most effective tools and how they help us to understand and optimize our accelerators.

Wherever possible theoretical predictions are compared with experimental evidence.

The second topic is concerned with simulations for the optimized non-linear LHC model. In particular, what had been needed in terms of code development, computing facilities, organization of large scale simulation campaigns and the LHC dynamic aperture experiment.

In closing, recent FCC-ee code developments will be outlined.

30. 11. 2021 - Irma Shmidt


Vibration studies at BESSY II - from ground to magnets to beam (Report Master Thesis)



14. 12. 2021 - Markus Ries


TRIBs with 1.75 GHz beating - an end game idea for BESSY II




Archive of previous talks