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Daniel Hagedorn and Frank Löffler
Physikalisch-Technische Bundesanstalt
Braunschweig and Berlin, Germany


“Manufacturing Test Masses for the Evaluation of the Equivalence Principle”

Location: Physics/Astrophysics Building, Conference Rooms 102 & 103
Monday, May 5, 2008, 4:00 – 5:30 pm
Light refreshments available 4pm; Presentation begins 4:15pm. Open to all.


The performance of experimental investigations into the principle of equivalence, e. g. the Drop Tower Experiment in Bremen, Germany, or the orbit based Microscope and STEP experiments, requires test masses of the highest precision with respect to homogeneity, form and dimensions. The technical demands resulting from theoretical considerations require a state of the art raw material production, fabrication of the functional surfaces and coating technology. New courses of fabrication have to be developed or optimized for these special tasks. The metrology to be applied after each production step is of particular importance for compliance with the requirements.
The Physikalisch-Technische Bundesanstalt (PTB), situated in Braunschweig and Berlin, Germany, is the German National Metrology Institute (NMI). Hence, PTB’s Scientific Instrumentation Department has the great advantage to be able to verify new and self-developed machine-base in-situ measuring techniques by means of national primary standards, e.g. length, form and dimension, mass, density or thermal expansion to name but a few, allowing an unrivalled precision.

Frank Löffler
Diplom in Mechanical Engineering, Dr.-Ing. in Thin Film Technology, Habilitation in Risk Assessment of New Technologies and apl. Prof. in Environmental Aspects in Material Science at RWTH Aachen University. Scientific employee (1986 – 1990) and Chief engineer (1990 – 1995) at RWTH Material Science Institute. Scientific employee (1995 – 1998) and head of the department Scientific Instrumentation (since 1998) at PTB the National Metrology Institute.
Daniel Hagedorn
Graduated Physicist; Dr. rer. nat. in Semiconductor and Quantum Physics (major), Microsystem Technology and Astrophysics (minor);
Thesis: Fabrication and Measuring of Superconducting Digital Electronic Circuits;
Scientific employee at PTB’s Quantum Electronics Department (1999-2006) and Scientific Instrumentation Department (since 2006);
Head of the Surface Technology Working Group (since 2008).


See Karolyn Zeng's exhibition “Celestial Journeys: In the Language of Art” through May 31, 2008 in the Physics and Astrophysics Building, 8am-5pm M-F. The artist reflects on astrophysics, quantum physics, human genetics and the I Ching in nineteen Oil on Canvas paintings, which range from the use of ancient Chinese calligraphy to large, multi-canvas works fusing human genetics and cosmology.

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Previous HEPL Seminars 2004, 2005, 2006, 2007, 2008:

Daniel Hagedorn and Frank Löffler
Physikalisch-Technische Bundesanstalt
Braunschweig and Berlin, Germany
“Manufacturing Test Masses for the Evaluation of the Equivalence Principle”
Monday, 5 May 2008

Bob Kline-Schoder, Ph.D.
Principal Engineer and Vice President from Creare Inc., Hanover, NH
“Resuscitating the Hubble Space Telescope With a Cryogenic Refrigerator”
Odile Clavier, Ph.D.
Engineer from Creare Inc., Hanover, NH
“Hearing Assessment System for Space Station Astronauts and Other Research in Human Hearing”
Wednesday, March 12, 2008

Dr. Martin Tajmar, MSS
Head of Space Propulsion & Advanced Concepts
Austrian Research Centers GmbH - ARC
“LISA Thrusters and the Search for Frame Dragging at Low Temperatures at ARC”
Wednesday, February 20, 2008

Dr. Stefan Funk
Assistant Professor, Physics, Stanford University and SLAC
“Gamma-ray astronomy: Status and Future Directions”
Wednesday, January 30, 2008

Dr. Joerg Wagner
University of Stuttgart
“The Origin of the Modern Gyroscope: Bohnenberger's Machine and the Scientific Work of its Inventor”
January 16, 2008

Professor Bob Bingham
Rutherford Appleton Laboratory
“Probing Quantum Gravity Using Matter”
Wednesday, December 12, 2007

Richard N. Boyd
Science Director, National Ignition Facility
Lawrence Livermore National Laboratory
“Creating a Star in the Laboratory: the National Ignition Facility”
Wednesday, November 28, 2007

Domenico Gerardi
Visiting researcher, Hansen Experimental Physics Laboratory, Stanford University
PhD candidate, University of Stuttgart and Science Missions & Systems EADS Astrium
“Achieving disturbance reduction for future drag-free missions. ”
Wednesday, October 24, 2007

Fabio Scardigli
Department of Physics, University of Milano, Italy
"The Equivalence Principle, the Uncertainty Principle and Some Fundamental Physics Questions"
Wednesday, May 23, 2007

Dr. Daniel Lebach
Harvard-Smithsonian Center for Astrophysics
“Seeing spots: a report on optical and very-long-baseline radio interferometry
observations of IM Pegasi, the guide star for the Gravity Probe B mission. ”

Wednesday, May 9, 2007

Dr. Gregory P. Crawford, Dean of Engineering and Professor of Engineering & Physics
Brown University, Division of Engineering
In Vivo Spectroscopy for Blood Analyte Monitoring
Wednesday, April 25, 2007

Professor C.W. Francis Everitt
W.W. Hansen Experimental Physics Laboratory, Stanford University
“Maxwell at 175 ”
Wednesday, March 14, 2007

Paul Brink
Department of Physics, Stanford University speaking for the (Super)CDMS collaboration
“Present status and future plans of the Cryogenic Dark Matter Search (CDMS)”
Wednesday, February 28, 2007

Alfred Vogel
Institute of Biomedical Optics University of Lübeck, Germany
“New findings on plasma and cavity generation in aqueous media with fs and ns laser pulses, and their applications in cell surgery"
Thursday, January 25, 2007

Dr. Dan McCleese
Chief Scientist, Jet Propulsion Laboratory
“Recent Results and Future Direction of the Exploration of Mars"
Tuesday, September 26, 2006

Ned Wright
Professor of Physics and Astronomy, UCLA
What's New in Cosmology?

Thursday 9 March 2006

Peter Michelson
Stanford University
GLAST: The Gamma-ray Large Area Space Telescope Mission
Seminar and Tour

Thursday 16 Feb 2006

Robert L. Byer
Stanford University
"Acceleration of Electrons with Visible Light"

Wednesday 1 Feb 2006

Emeline Guiu
Office National d’Etudes et de Recherches Aérospatiales (ONERA)
The MICROSCOPE Mission and In-Flight Calibration
Emeline Guiu, Danya Hudson

Wed 7 Dec 2005

Dr. Nicholas White
Chief, Laboratory for High Astrophysics NASA Goddard Space Flight Center
“The NASA Beyond Einstein Program”

Wed 5 Oct 2005

Ulrich Schreiber, Forschungseinrichtung Satellitengeodäsie, TU-München
“High Precision Sagnac Interferometry for Applications in Geoscience ”
Thursday, September 8, 2005

Christopher D. Bass, Indiana University / IUCF, “Measurement of the Parity-Odd Neutron Spin Rotation in Liquid-4He”
Monday, August 22, 2005

Anne Kinney, Director, Universe Division in the Science Mission Directorate, NASA, "Blue Planets, Black Holes"
Wednesday, 20 July 2005

Dr William Tobin, Department of Physics & Astronomy, University of Canterbury, New Zealand, "Foucault's Gyroscope of 1852"
Friday, 8 April 2005

Rex Geveden, NASA Chief Engineer, Independent Technical Authority
7 April 2005

Shooting the Moon: Probing Fundamental Gravity in the Solar System
Tom Murphy, UC San Diego 3 March 2005

The GRACE Mission: Status and Science Results John Ries, Senior Research Scientist at the Center for Space Research at The University of Texas at Austin, 14 February 2005.

Hubble Robotic Servicing - Recent Engineering Development, Bill Reeve
Civil Space Director of Advanced Science Programs, Lockheed Martin, 26 January 2005.

Interferometry for LISA, Daniel Shaddock, PhD, Interferometry Metrology and Optics Group, Jet Propulsion Laboratory, 17 November 2004.

The Large Synoptic Survey Telescope (LSST), Steve Kahn, Deputy Director, Kavli Institute for Particle Astrophysics and Cosmology, 27 October 2004.

HEPL-KIPAC Showcase. 29 September 2004. Agenda