EuroTeV WP7 activities at DESY Group Members: R. Amirikas, A. Bertolini, W. Bialowons, H. Ehrlichmann Total Man Power: 1.5 reaching 2 (maximum)

EuroTeV WP7-METSTAB Metrology Oxford & GeoDESY: LiCAS – Rapid tunnel reference system (Surveying) DESY: Site characterization and parameterization of data DESY: Correlation measurements; related to site characterization DESY: Floor motion due to building foundation (e.g. piled foundation & floor slabs) Stabilization LAPP: CLIC vibration isolated platform – ATF Final Doublet LAPP: Active vibration suppression studies at Final Focus Oxford: StaFF – 6 degrees of freedom LiCAS+Michelson Interferometer at FF DESY: Accelerator component vibration studies:  Cryomodule vibration studies in warm and cold environments, geared towards main linac design (one of the main cost drivers for the ILC)  Stability of support structures, such as girders  Facility noise: potential vibration sources in a tunnel, e.g. vacuum pumps, modulators

Metrology: site measurement & chracterization  Study the impact of ‘cultural f >1 Hz, at several accelerator laboratories & synchrotron light sources  19 sites are measured so far. Database available: (H. Ehrlichmann & H. Molsen)  Same equipment and data analysis tools are applied to each case; Therefore, direct comparison is possible  This work will continue albeit with a lower priority, often combined with other measurements  Publications: presentations in Nanobeam2005 (R. Amirikas) and in EPAC06, in preparation, (H. Ehrlichmann) Power spectral densities for five measured sites

Metrology: site characterization via parameterization (in collaboration with D. Kruecker (DESY)) & Correlations  Parameterization of power spectral densities measured, reperesenting ‘noisy’, ‘quiet’ and ‘medium’ sites; This is done via root; Model is obtained from V. Shiltsev et al, DESY HERA  Measurement of correlation length of a few sites, including DESY  Study of floor motion (a civil engineering issue) as opposed to ambient ground motion (influenced by geology in each site) A fit to the power spectral density of Petra (preliminary)

 Study of support structures, e.g. girders is important for the stability of the cryomodules in the ILC; MaxLab girder measurements (visit funded by ALBA) Vertical vibration measurement via a seismometer, transfer function girder/ground 1 Hz Stability of accelerator components; case study: MAXLab (Lund) girder

Horizontal vibration (longitudinal to the beam direction) measurement via geophones, Resonance: ~28-30 Hz, transfer function, 1.7 Hz Horizontal vibration (transverse to the beam direction) measurement via a seismometer, resonances: ~15-16 & 30 Hz, transfer function, girder/ground 1 Hz

Stability of accelerator components: Measurement of the stability of a ‘warm’ cryomodule (Superstruktur) With quadrupole (back view) With quadrupole (side view)

Without quadrupole, as it is now! Helium pipe Stability of accelerator components: Measurement of the stability of a ‘warm’ cryomodule (Superstruktur) Integrated vertical vibration for f > 1 Hz as measured via geophones of Helium pipe vs. quadrupole, Vessel resonances seen in the Helium pipe: ~4.3, 9.0 Hz, seen also on the quadrupole: ~4.2, 9.0 Hz, 1 Hz: Quad/Helium~1.06 or ~10%

Stability of accelerator components: Measurement of the stability of a ‘warm’ cryomodule (Superstruktur) Integrated transverse vibration for f > 1 Hz as measured via seismometers, 1 Hz: Top/Helium~1.22, or ~22% PSD in transverse direction to the beam pipe as measured via seismometers, Vessel top vs. Helium pipe, Resonances: ~4.3, 8.0, 9.0 Hz

Stability of accelerator components: Measurement of the stability of a ‘warm’ cryomodule (Superstruktur) Integrated transverse vibration for f > 1 Hz as measured via seismometers, 1 Hz: Top/Ground~ 10 PSD in transverse direction to the beam pipe as measured via seismometers, Vessel top vs. Ground, Vessel resonances: ~4.3, 8.0, 9.0 Hz Amplification factor for Ground/Quad = Top/Ground*Helium/Top*Quad/Helium =10.0*0.80*1.06= 8.48 ~10

Motivation: Evaluate the rigidity of the quad supporting structure to confirm 1:1 vessel to quad transfer function (in warm and cold) Evaluate quantitatively return He-flow contribution, perhaps with different flow rates Use the same setup to test other interferometric position sensors (Oxford ) & POLYTEC Technique: Place two 'mirrors‘ directly on the cold quadrupole He vessel Measure their motion with respect to a reference frame by means of a laser interferometer (self-calibrated, sub-nanometer resolution etc.); measure the frame motion with a seismometer Use different reference frames can provide different information and offer data-quality check Reference frames: ground, inertial platform, cryomodule vessel (essential to measure small amplitude differences, otherwise the vessel rocking modes dominate the dynamics) Cold mass test plan

front view side view bottom view Type III+ cryomodule with the proposed modifications Figures: courtesy of C. Engling (DESY, MKS)

 Optical access now integrated in the cryomodule design  Two anti-reflection coated viewport towards the insulation vacuum  Two lines of sight opened through the thermal shields  To be assembled at DESY by October 2006; available for warm measurements in November  Cold test, sometime early in 2007 Cryomodule Type III+ Fiber optic head Geophone (inertial measurement)

Extra Slides

INERTIAL SENSING CLIC Table (CERN + LAPP Annecy) – destinated to ATF for the final doublet stabilization; standard honeycomb optical bench with Stacis feet (feedback by piezoelectric actuators on signal from integrated geophones and piezo-accelerometers). In the CLIC design in the nearly DC the sensor authority is released to capacitance position sensors referred to the ground. Few nanometer RMS residual 1Hz proven. Only a technology demonstrator; not usable in ILC. final focus cold mass active stabilization (LAPP) – active damping of the internal modes of the superconducting beam-shaped cold quadrupole; mock-up built and FEA modeled, feedback algorithm tested. Everything must fit inside the FF cryostat! Promising solution for the actuator found (PIEZO). More problems for the accelerometer(s). Two different philosophies: WP7-METSTAB

POSITION SENSING (…the BCD choice at the FF..) LiCAS (Oxford + GeoDESY) – interferometric techniques to automatically measure a network of reference position markers of a tunnel with an accuracy of 200 micron over distances of 600 meters (0.3 ppm), using FSI position sensors and LSMs. The idea is to have a 25m long survey train running over the 30 Km tunnel to establish a coordinate system of reference marks against which the collider components will be surveyed. Prototypes etc. StaFF - Use the same LiCAS framework: fiber optic tunable laser+Erbium-doped-fiber amplifier (EDFA) + reference interferometer for high accuracy FF components relative position survey. New multifiber optical head for higher accuracy (30 nm in simulations) and faster position reconstruction. Use the same optical path and head with a narrow linewidth fixed frequency laser for vibration measurement in Michelson interferometer mode (sub nanometer resolution achievable, with in-vacuum path). The idea is to use these components + a LSM to refer one-each- other the two FF units at the IP, for diagnostics and/or stabilization.