European XFEL in 2017 aus Operateurssicht

Operation Milestones in 2017, Meinungen aus Reihen der Operateur

Entwicklung und Aufbau einer Schaltung zur Bestimmung der Elektronenbündellänge im Linearbeschleuniger über verschiedene Moden eines Resonators

In dieser Arbeit wird eine Schaltung entworfen, um die Elektronenbündellänge im Linearbeschleuniger zu bestimmen. Des Weiteren wird der mathematische Hintergrund hierzu erläutert und die minimal bestimmbare Bunchlänge bedingt durch die Messungenauigkeit ermittelt.Within this work a circuit is designed to determine the electron bunch length in a linear accelerator. Furthermore, this explains the mathematical background and calculates the minimum identifiable bunch length determined by the measurement uncertainty

A Fast Wire Scanner System for the European XFEL and Its Impact on SafetySystems

The European-XFEL is an X-ray Free Electron Laser facility located in Hamburg (Germany). The 17.5 GeV superconducting accelerator will provide photons simultaneously to several user stations. Currently 12 Wire Scanner stations are used to image transverse beam profiles in the high energy sections. These scanners provide a slow scan mode for singlebunch operation. When operating with long bunch trains(>100 bunches) fast scans are used to measure beam sizes in an almost nondestructive manner. To operate fast scans multiple impacts on the beam loss system (BLM) and the charge transmission interlock (TIS) have to be taken into account.This paper focusses on the interaction between these systems and first experiences performing measurements

First Tests Using Sipm Based Beam Loss Monitors at the European XFEL

The European XFEL uTCA based Beam Loss Monitor System (BLM) is composed of about 470 monitors using photomultiplier tubes (PMTs). BLMs installed in the SASE undulator intersections show high signals at electron energy higher 16 GeV or photon energy higher14 keV due to background synchrotron radiation which directly affects the PMT. The amplitude of this signal canged that high that, also without using any detector material, the BLMs get blind for real losses. Also different lead arrangements did not shield the signal sufficiently.First tests show that a Silicon photomultiplier (SiPM) is not affected. Also there are several advantages to use SiPM, they are cheaper by factor of 40 and operating voltage is below 35V. First test results will be presented and how it can get implemented in the existing BLMs and BLM system

The European XFEL Beam Loss Monitor System

The European XFEL MTCA based Beam Loss Monitor System (BLM) is composed of about 470 monitors, which are part of the Machine Protection System (MPS). The BLMs detect losses of the electron beam, in order to protect accelerator components from damage and excessive activation, in particular the undulators, since they are made of permanent magnets. Also each cold accelerating module is equipped with a BLM to measure the sudden onset of field emission (dark current) in cavities. In addition some BLMs are used as detectors for wire- scanners. Experience from the already running BLM system in FLASH2 which is developed for XFEL and tested here, led to a fast implementation of the system in the XFEL. Further firmware and server developments related to alarm generation and handling are ongoing.The BLM systems structure, the current status and the different possibilities to trigger alarms which stop the electron beam will be presented

First Tests of a Micro-TCA-Based Downconverter Electronic for 5GHz Higher Order Modes in Third Harmonic Accelerating Cavities at the XFEL

Beam excited higher order modes (HOM) in 3.9GHz accelerating cavities at the European XFEL are planned to be used for beam position monitoring. The specifications of the monitors have been defined during an extensive study on the 3.9GHz module at FLASH. Selected HOMs for precision measurement are located around 5440MHz and 9040MHz. An electronics developed by FNAL has been recently installed at FLASH and provides a basis for the XFEL electronics. The paper will present the design and first test of the hardware for the Micro TCA standard used for the XFEL. The hardware consists of three different Rear Transition Modules (RTM), two four channel down converter RTMs (5GHz and 9GHz) and a third RTM with two phase locked loop synthesizers on board for LO generation. Presently the 5GHz and the PLL RTMs are under construction. The first measurements with these cards will be presented

The European XFEL Beam Loss Monitor System

The European XFEL MTCA based Beam Loss Monitor System (BLM) is composed of about 470 monitors, which are part of the Machine Protection System (MPS). The BLMs detect losses of the electron beam, in order to protect accelerator components from damage and excessive activation, in particular the undulators, since they are made of permanent magnets. Also each cold accelerating module is equipped with a BLM to measure the sudden onset of field emission (dark current) in cavities. In addition some BLMs are used as detectors for wire- scanners. Experience from the already running BLM system in FLASH2 which is developed for XFEL and tested here, led to a fast implementation of the system in the XFEL. Further firmware and server developments related to alarmg eneration and handling are ongoing.The BLM systems structure, the current status and the different possibilities to trigger alarm

Higher Order Modes Based Beam Phase Study : Simulations and Measurements

– A brief introduction to the European XFEL and Higher Order Modes– Principle of beam phase determination– Simulations with circuit model– Measurements with a broadband setup– Summary and Outloo

HOM Characterization for Beam Diagnostics at the European XFEL Injector

Higher Order Modes (HOM) excited by bunched electron beams in accelerating cavities carry information about the beam position and phase. This principle is used at the FLASH facility, at DESY, for beam position monitoring in 1.3 and 3.9 GHz cavities. Dipole modes, which depend on the beam offset, are used. Similar monitors are now under design for the European XFEL. In addition to beam position, the beam phase with respect to the accelerating RF will be monitored using monopole modes from the first higher order monopole band. The HOM signals are available from two couplers installed on each cavity. Their monitoring will allow the on-line tracking of the phase stability over time, and we anticipate that it will improve the stability of the facility. As part of the monitor designing, the HOM spectra in the cavities of the 1.3 and 3.9 GHz cryo-modules installed in the European XFEL injector have been measured. This paper will present their dependence on the beam position. The variation in the modal distribution from cavity to cavity will be discussed. Based on the results, initial phase measurements based on a fast oscilloscope have been made