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Performance Degradation of the Low Level RF Control System for VUV-FEL. Tomasz Jeżyński. Technical University of Łódź , Poland Deutsches Elektronen-Synchrotron, Germany. Outlook. VUV-FEL LLRF Source of perturbations Proposal for diagnostic. VUV-FEL - the pilot facility for the XFEL.
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Performance Degradation of the Low Level RF Control System for VUV-FEL Tomasz Jeżyński Technical University of Łódź, Poland Deutsches Elektronen-Synchrotron, Germany
Outlook • VUV-FEL • LLRF • Source of perturbations • Proposal for diagnostic Tomasz Jeżyński
VUV-FEL - the pilot facility for the XFEL • 260 m long (tunel 100 m) • 6 Kyro Modules • TESLA technology • 48 superconductive cavities • Development platform for XFEL Tomasz Jeżyński
Kyro module Tomasz Jeżyński
Inside the tunnel Tomasz Jeżyński
Tunnel Tomasz Jeżyński
Low Level Radio Frequency – Goal(s) Provide stable RF field in cavity during beam • continuous operation Tomasz Jeżyński
LLRF - requirements • Electrical field : 30 MV/m • Required field stability : 10-5 in amplitude, 0.01° in phase • Continuous operation is required one maintenance day per month Tomasz Jeżyński
Low Level Radio Frequency System Tomasz Jeżyński
Source of perturbation MO – phase VM – Pin, nn Klyston – Pout = f(Pin) RF Power distribution Probes – individual char Mixers – nn, offset ADCs – nn, offset Numerical errors DACs – nn, offset Timing – time & temp. Supplies Noise Tomasz Jeżyński
Diagnostic of LLRF - Goals • Provide continuous operation of LLRF System • Reduce maintenance cost Tomasz Jeżyński
Measurements points in LLRF Tomasz Jeżyński
VS and signal from single cavity Tomasz Jeżyński
Mean & std. of measured signals (VS) Tomasz Jeżyński
Field Phase in Vector Sum Tomasz Jeżyński
Unacceptable data from the system Tomasz Jeżyński
LLRF in VUV-FEL Tomasz Jeżyński
Diagnostic for VUV-FEL Tomasz Jeżyński
What we know about EU-XFEL ? • What we know? • Technology is unknown • Structure (distributed? links?) • Algorithms (under development) • Diagnostic have to be: • Cheap • Flexible (easy modification, extend...) • Integrated with system • But, failures of diagnostic cannot stop operation Tomasz Jeżyński
Proposal for diagnostic • Monitoring • Diagnostic • Calibration Tomasz Jeżyński
Monitoring • Error detection • Timing signals (synchronization, phase) • Pfor & Pref • Probes • Field stability (RMS, p-p, ...) • Detuning • Loaded Q • Limits of set value • ... Tomasz Jeżyński
Diagnostic • Detect malfunction • Locate damage hardware • Perform components tests • ADCs, DACs • Interfaces • Memory, DSP blocks ... • Timing distribution • ... Tomasz Jeżyński
Calibration • Timing • Correction of parameters • Probes • Downconverters • ADCs & DACs offset • ... • Piezo tuning • ... Tomasz Jeżyński
Recommendations • Provide possibility to read data form different points of the system • Design the universal diagnostic interface and implement it to all electronic boards • Integrate diagnostic elements in control system • Sources of test signals • RF Switches • ... • Provide self diagnostic for all boards Tomasz Jeżyński
Conclusion It is possible to predict operation interrupt before it happens The diagnostic system should be integrated with control system and hardware Base on experience from TTF and VUV-FEL the diagnostic system will decgrease maintenance cost Tomasz Jeżyński
END Tomasz Jeżyński
Measurements points in LLRF Tomasz Jeżyński