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Since end of the year 2020 the energy recovery linac (ERL) project bERLinPro of Helmholtz-Zentrum Berlin has been 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 broadening of applications of this machine from high current SRF based energy recovery concept up to an ultrafast electron diffraction (UED) facility producing shortest electron pulses, the facility is now named Sealab, Superconducting RF Electron Accelerator Laboratory. In this contribution, an overview of lessons learned so far, the status of the machine, the coming set up and commissioning steps with an outlook to midterm and future applications will be given. In summary, Sealab will expand, including the ERL application, and become a general accelerator physics and technology test machine to employ UED as a first study case and will also be an ideal testbed to investigate new control schemes based on digital twins or machine learning methods., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

With the 1.5 GHz couplers for the Variable pulse length Storage Ring (VSR) DEMO now in the manufacturing stages, the studies that led to the final coupler design will be presented. The system specific constraints and design modifications that combat the challenges of thermomechanical stresses, higher order mode (HOM) propagation and dimensional constraints are explored. This includes S-Parameter analysis, an in-depth study of the coupling factor, and multipacting studies for the average (1.5 kW) and peak (16 kW) power., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

BERLinPro is an energy recovery linac (ERL) demonstrator project built at HZB. It features CW SRF technology for the low emittance, high brightness gun, the booster module and the recovery linac. Construction and civil engineering are mostly completed. Synchronized with the device integration the EPICS based control system is being set-up for testing, commissioning and finally operation. In the warm part of the accelerator technology is used that is already operational at BESSY and MLS (e.g. CAN-bus and PLC/OPCUA). New implementations like the machine protection system and novel major subsystems (e.g. LLRF, Cryo-Controls, photo cathode laser) need to be integrated. The first RF transmitters have been tested and commissioned. Around the time of this workshop the first segment of the accelerator is scheduled to become online. For commissioning and operation of the facility the standard set of EPICS tools form the back-bone. A set of generic python applications already developed at BESSY/MLS will be adapted to the specifics of BERLinPro. Scope and current project status are described in this paper., Proceedings of the 63th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs, ERL2019, Berlin, Germany

The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a SRF based demonstration facility for the science and technology of ERLs for future high power, high brilliance electron beam applications. BERLinPro was designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. Given the recent prioritization of the BESSY II upgrade to the BESSY VSR variable pulse length storage ring, HZB is forced to reduce the project goals of BERLinPro. As a result, the project had to be rescoped with the goal to maximize its scientific impact within the present boundary conditions. We report on the last year’s progress of the building, the warm and cold infrastructure and on the time line, goals nd opportunities for the remaining project run time., Proceedings of the 63th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs, ERL2019, Berlin, Germany

The Helmholtz Zentrum Berlin is carrying out two accelerator projects which make use of high gradient SRF cavities: BERLinPro* and BESSY-VSR**. In both projects, a prompt detection of a quench is crucial to avoid damages in the cryomodules and cavities themselves. In this paper, the response of real time estimation of the cavity parameters*** using the transmitted and forward RF signals is simulated, in order to perform the quench detection. The time response of the estimated half bandwidth is compared with the dissipated power in the cavity walls for the different type of SRF cavities used in both projects, i.e., BERLinPro’s photoinjector, booster and linac, and BESSY-VSR 1.5 GHz and 1.75 GHz cavities. As an intermediate step prior to the implementation in an mTCA.4 system together with the LLRF control and test with a real cavity, the algorithm has been implemented using a National Instruments FPGA board to check the its proper behavior., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Setting up and debugging SRF support systems, such as LLRF control, quench detection, microphonics and Lorentz-force detuning control, etc., often requires extensive time spent operating the cavities. This results in time consuming and costly operation. Early into the development stages the actual cavity system may not even be available. It is therefore highly desirable to pre-evaluate these systems under realistic conditions prior to final testing with the SRF cavities. We devised an FPGA-based "virtual cavity" that takes a regular low-level RF input and generates the signals for RF-power reflection, transmission and detuning that mimic the response of a real cavity system. As far as the user is concerned, the response is the same as for a real cavity. This "black-box" model includes mechanical modes, Lorentz force detuning, a field depended quality factor, quenches and variable input coupling and is currently being expanded. We present the model and show some applications for operating the quench detection, LLRF and microphonics control for 1.3 GHz BERLinPro cavities. The same system can be used for other cavity types, including normal conducting cavities., Proceedings of the 19th International Conference on RF Superconductivity, SRF2019, Dresden, Germany

The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a demonstration facility for the science and technology of ERLs for future light source applications. BERLinPro is designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the last year's progress, including the comissioning of the gun module as the first SRF component to be installed in BERLinPro., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Helmholtz-Zentrum Berlin (HZB) is currently constructing a high average current superconducting (SC) ERL as a prototype to demonstrate low normalized beam emittance of 1 mm-mrad at 100 mA and short pulses of about 2 ps. To attain the required beam properties, an SRF based photo-injector system was developed and during the past year underwent RF commissioning and was setup within a dedicated diagnostics beamline called Gunlab to analyze beam dynamics of both, a copper cathode and a Cs2KSb cathode as well as their quantum efficiency at UV and green light respectively. The medium power prototype - a first stage towards the final high power 100 mA design - presented here features a 1.4 x λ/2 cell SRF cavity with a normal-conducting, high quantum efficiency CsK2Sb cathode, implementing a modified HZDR-style cathode insert. This injector potentially allows for 6 mA beam current and up to 3.5 MeV kinetic energy, limited by the modified twin TTF-III fundamental power couplers. In this contribution, the first RF commissioning results of the photo-injector module will be presented including dark current analysis as well as measured beam properties with an initially installed Copper cathode., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The availability of niobium superconducting cavities, ei-ther due to a lack of a real cavity or due to the time needed for the experiment set up (vacuum, cryogenics, cabling, etc.), is limited, and thus it can block or delay the develop-ment of new algorithms such as low level RF control. Hardware-in-the-loop simulations, where an actual cavity is replaced by an electronics system, can help to solve this issue. In this paper we present a Cavity Simulator imple-mented in a National Instruments PXI equipped with an FPGA module. This module operates with one intermedi-ate frequency input which is IQ-demodulated and fed to the electrical cavity's model, where the transmitted and re-flected voltages are calculated and IQ-modulated to gener-ate two intermediate frequency outputs. Some more ad-vanced features such as mechanical vibration modes driven by Lorentz-force detuning or external microphonics have also been implemented. This Cavity Simulator is planned to be connected to an mTCA chassis to close the loop with a LLRF control system., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

MESA at the Institut für Kernphysik (KPH) at Johannes Gutenberg-Universität Mainz is a multi-turn energy recovery linac (ERL), aiming to serve as user facility for particle physics experiments. The RF-accelerating systems of MESA consist of four 9-cell TESLA superconducting cavities, four normal conducting (NC) pre-accelerator cavities, two NC buncher cavities and two NC chopper cavities. They operate in continuous wave (CW) mode. In order to control the radio frequency (RF) amplitude and phase within the 12 cavities with the required accuracy and stability in the range of better than 0.01% and 0.01°, the MicroTCA.4 based digital low-level RF (LLRF) control system based on the development at DESY, Hamburg will be well adapted for the MESA cavities. In this paper, we describe the theoretical modelling of superconducting cavity and PID controller in SIMULINK which is useful to find the suitable control parameter for the PID controller and to predict the system performance. The progress to date of the implementation and tests of the LLRF system at MESA will also be presented., Proceedings of the 29\textsuperscript{th} Linear Accelerator Conf., LINAC2018, Beijing, China

Continuous wave operated superconducting cavities experiencing small net beam loading and thus operate potentially at narrow bandwidth require precise detuning control to reach the high stability requirements for RF fields within facilities as FEL or ERL based photon sources. Especially microphonics compensation down to sub-hertz detuning regime besides improving stability reduces the risk of rise of Lorentz force detuning driven ponderomotive instabilities. Usually the complex and second order nature of the mechanical to RF detuning transfer functions of cavity and cavity-tuner system require for more advanced control schemes. In this paper we will show the application of a Kalman filter based detuning estimator algorithm first introduced during IPAC2017 [1] to the SRF cavity simulator developed at Helmholtz Zentrum Berlin [2]. Results using the algorithm in observer mode to detuning compensation attempts in closed loop mode are presented., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The Superconducting RF (SRF) photoinjector programme for the energy-recovery linac (ERL) test facility BERLinPro sets out to push the brightness and average current limits for ERL electron sources by tackling the main challenges related to beam dynamics of SRF photoinjectors, the incorporation of high quantum efficiency (QE) photocathodes, and suppression of unwanted beam generation. The paper details the experimental layout of the SRF photoinjector and the gun test facility GunLab at Helmholtz-Zentrum Berlin., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

For CW driven superconducting cavities operating at small bandwidth, like in ERL or FEL light sources, it is mandatory to precisely control any source of detuning. Therefore, a Kalman [1] filter based approach was developed and implemented as FPGA firmware to act as the core part of a detuning compensation algorithm. It relies on a fit by a second order model to a measured transfer function of cavity's forced oscillations with damping, caused by piezo drives and data about observed current phase with some adjustable confidence rate. The initial data for this core is taken from field detection firmware on mTCA.4's SIS8300-L2 digitizer, transferred by low latency links to a carrier board equipped by piezo drive controller where the DSP processing by the Kalman algorithm performed. The processing is characterized by a 550 kHz rate in pipeline mode and occupies almost all DSP resources of the Spartan 6 FPGA chip. The experimental results of detuning compensating technique applied to a SC photoinjector cavity are presented in this contribution., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a demonstration facility for the science and technology of ERLs for future light source applications. BERLinPro is designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project status. This includes the completion of the building and the installation of the first accelerator components as well as the assembly of the SRF gun and GunLab beam diagnostics, which are now ready for commissioning., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

Helmholtz-Zentrum Berlin (HZB) is currently designing and building an high average current all superconducting CW driven ERL as a prototype to demonstrate low normalized beam emittance of 1 mm·mrad at 100mA and short pulses of about 2 ps. In order to achieve these demanding goals HZB started a staged program for developing this class of required high current, high brightness SRF electron sources. In this contribution we will present the current status of the module assembly and testing of the prototype SRF photo-injector cavity cold string. The steps taken to install the cathode insert system with the cavity in the cleanroom and the following horizontal test of the cold string as final acceptance test prior installation into its cryostat are shown. First beam in a dedicated diagnostics teststand called Gunlab are planned for this winter., Proceedings of the 28th Linear Accelerator Conf., LINAC2016, East Lansing, MI, USA

8th International Particle Accelerator Conference, IPAC17, Copenhagen, Denmark, 15 May 2017 - 19 May 2017 ; Geneva : JACoW, 3966-3968(2017). doi:10.18429/JACoW-IPAC2017-THPAB106, We present a compact RF control system for SCRF single cavities based on MicroTCA.4 equipped with specialized advanced mezzanine cards (AMCs) and rear transition modules (RTMs). To sense the RF signals from the cavity and to drive the high power source, a DRTM-DWC8VM1 module is used equipped with 8 analog field detectors and one RF vector modulator. Fast cavity frequency tuning is achieved by piezo-actuators attached to the cavity and a RTM piezo-driver module (DRTM-PZT4). Data processing of the RF signals and the real-time control algorithms are implemented on a Virtex-6 FPGA and a Spartan FPGAs within two AMCs (SIS8300-L2V2 and DAMC-FMC20). The compact single cavity control system was tested at Cryo Module Test Bench (CMTB) at DESY. Software and firmware were developed to support all possible modes, the short pulse (SP), the long pulse (LP) and CW operation mode with duty cycles ranging from 1 % to 100%. The SP mode used a high power multi-beam klystron at low QL ~3·10⁶. For the LP mode (up to 50% duty cycle) and the CW mode a 120 kW IOT tube was used at QL up to 1.5·10⁷. Within this paper we present the achieved performance and report on the operation experience on such system., Published by JACoW, Geneva

The goal of Berlin Energy Recovery Linac Project (BERLinPro) is the generation of a 50 MeV, 100-mA low emittance (below 1 mm mrad) CW electron beam at 2 ps rms bunch duration or below. Three different types of 1.3 GHz SRF modules will be employed: the electron gun, the booster and the main linac. Precise RF amplitude and phase control are needed due to the beam recovery pro-cess. In this paper we describe the first tests of the Low Level RF control of the first injector prototype at the HoBiCaT facility, implemented in the digital VME-based LLRF controller developed by Cornell University. Tuner movement control by an mTCA.4 system, together with further plans of using this technology will be also presented., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

We want to summarize the single cavity regulation with MTCA.4 electronics. Presented solution is based on the one MTCA.4 crate integrating both RF field control and piezo tuner control systems. The RF field control electronics consists of RTM for cavity probes sensing and high voltage power source driving, AMC for fast data processing and digital feedback operation. The piezo control system has been setup with high voltage RTM Piezo driver and low cost AMC based FMC carrier. The communication between both control systems is performed using low latency link over the AMC backplane with data throughput up to the 3.125 Gbps. First results from CW operation of the RF field controller and the cavity active resonance control with the piezo tuners are demonstrated and briefly discussed., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The Helmholtz Zentrum Berlin is constructing the Energy Recovery Linac Project BERLinPro on its site in Berlin Adlershof. The project is intended to expand the required accelerator physics and technology knowledge mandatory for the design, construction and operation of future synchrotron light sources. The project goal is the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beamat 2~ps rms bunch duration or below. The planning phase of the project is completed and the design phase of most of the components is finished. Many of them have already been ordered. After some delay the construction of the building has started in February 2015. The status of the various subprojects as well as a summary of current and future activities will be given. Major project milestones and details of the project time line will be finally introduced., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

For the feasibility of the BESSY VSR upgrade project of BESSY II two higher harmonic systems at a factor of 3 and 3.5 of the ring's RF fundamental of 500 MHz will be installed in the ring. Operating in continuous wave at high average accelerating field of 20 MV/m and phased at zero-crossing, the superconducting cavities have to be detuned within tight margins to ensure stable operation and low power consumption at a loaded Q of 5·10⁷. The field variation of the cavities is mainly driven by the repetitive transient beam-loading of the envisaged complex bunch fill pattern in the ring. Within this work combined LLRF-cavity and longitudinal beam dynamics simulation will demonstrate the limits for stable operation, especially the coupling between synchrotron oscillation and RF feedback settings. Further impact by beam current decay and top-up injection shots are being simulated., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

[ANGLÈS]Future prospects for s'Abanell beach Author: Pablo Rey Echevarria Tutor: José A. Jimenez The erosion processes are causing destruction on the Spanish Mediterranean coast. In Catalonia, in the coastal town of Blanes, s'Abanell Beach is suffering a continuous decline since the seventies. During the last years, storms have extensively damaged different infrastructures: a desalination facility, nine pumping wells, several campsites, a promenade, a road, car parks and other buildings. In this work we have studied the beach erosion mainly due to longshore sediment transport southward. We present the most important events occurred on the beach and a detailed analysis of the movements suffered by the shore line and the beach nourishments that have been performed. We have calculated the evolutionary tendency of the beach by linear regression, the sedimentary balance due to longshore transport with shore line positions, the sedimentary balance with wave data by propagating waves to break with Snell formulation and the littoral transport with Kamphuis/Queens formulation. Furthermore, we have also studied the effect of storms on the beach profile produced by cross-shore sediment transport, as well as the minimum beach wide for a proper hinterland protection. It has been explained the beach failure on its recreational and protection functions calculating the size that it would need to fulfill them. Moreover we offer some proposals for action. Finally, in the conclusions we present the most relevant magnitudes of the processes studied. [CASTELLÀ] Perspectivas de futuro para la playa de s'Abanell Autor: Pablo Rey Echevarria Tutor: José A. Jiménez Los procesos erosivos están causando estragos en el litoral mediterráneo español. En Catalunya, en el municipio costero de Blanes, la playa de s’Abanell está sufriendo un retroceso continuo desde los años setenta. Durante los últimos años con los temporales se han sufrido numerosos daños en diferentes infraestructuras: instalaciones de una desaladora, nueve pozos de bombeo, varios campings, un paseo marítimo, un vial, aparcamientos y otros edificios. En este trabajo se ha estudiado la erosión que se produce en la playa principalmente debida al transporte longitudinal de sedimento en dirección Sur. Les presentamos los sucesos más relevantes que se han dado en la playa. Un análisis detallado de los movimientos sufridos por la línea de orilla y de las obras de alimentación que se han realizado. Se ha calculado la tendencia evolutiva de la playa mediante regresión lineal, el balance sedimentario por transporte longitudinal con posiciones de líneas de orilla, el balance sedimentario con datos de oleaje mediante la propagación del oleaje hasta rotura con la formulación de Snell y el transporte longitudinal con la formulación de Kamphuis/Queens. También se ha estudiado el efecto de los temporales en el perfil de la playa, con los cambios que produce mediante el transporte transversal del sedimento, así como el ancho necesario de la playa para la correcta protección del hinterland. Se ha expuesto que la playa incumple su función recreativa y de protección y se ha calculado el tamaño que necesitaría para poder cumplirlas además de ofrecer unas propuestas de actuación. Por último en las conclusiones se exponen las magnitudes más relevantes de los procesos estudiados.

The Helmholtz Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro at the Berlin Adlershof site. The project is intended to expand the required accelerator physics and technology knowledge mandatory for the design, construction and operation of future synchrotron light sources. The project goal is the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project progress: since spring 2015 the building is under construction, ready for occupancy in January 2017. The planning phase for the first project stage is completed for the warm machine parts, the SRF gun and partly for the SRF booster. Most of the components have been ordered and are in fabrication with some already delivered. An update of the status of the various subprojects as well as a summary of future activities will be given. Project milestones and details of the timeline will be reviewed., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea