The EGO R&D Program
Date: 22 September
EGO R&D program
EGO – The European Gravitational Observatory - in
order to fulfill one of his statutory missions, i.e, to
promote an open co-operation in R&D, has a specific
R&D budget for major Virgo upgrades, for new detectors
and, in general, for gravitational physics.
R&D contracts are open to all GW European laboratories.
Scope of the EGO R&D program
•EGO launched in Autumn 2002 the first call for R&D
proposals open to European groups regarding advanced GW
•To this call responded groups pertaining to the Virgo
collaboration, resonant detector groups, and groups in
Germany and UK.
•The proposals were examined by the EGO Scientific and
Technical Advisory Committee, the “STAC”.
•On STAC recommendation several R&D were financed by
The R&D program 2003-2005
• Funds allocated or committed in R&D contract distribution
years 2003-2006: 2,183 k€
• 25 Signed conventions/contracts 3rd Generation Current Virgo
with proponent laboratories
• 12 Fellowships contained in those
• Of these R&D programs the
repartition may be broadly shown
as in this graph
Adaptive optics for GW ITFs Naples University
CNRS OCA- ILGA
Virgo Control System upgrade IN2P3 LAPP
Surface corrective coatings for GW ITFs IN2P3 LMA
Full scale prototype of fused Silica Suspensions University Perugia
Improvement of Q measuring facility for mirrors University Perugia
Improvement of coatings Q University Perugia
Optimisation of interferometer optical parameters CNRS OCA-ILGA
Modelling of Thermal Noise University Perugia
Study of signal re-cycling IN2P3 LAL
Laser cooling of fibres Pisa University
CO2 laser for monolithic suspensions Glasgow University
Wide band transducer for Dual Torus detector University Padova
Spherical detector for high frequency gw U.Roma-2 Tor Vergata
Study of quantum noise CNRS LKB
Thermal Noise at Cryogenic Temperatures INFN Pisa and al
Data analysis of gw from coalescing BH Cardiff University
Study hollow fibre optics CNRS OCA - ILGA
Si absorption characterization a 1.5 mm ESPCI
the 2003-2005 R&D program status
Last April the STAC examined the
intermediate reports submitted
by most of the current contractors for the EGO R&D program
Hereafter, some elements of those reports and
of comments by STAC are reported.
Silicon Suspensions laser cooling University-Pisa
The research group reported successful demonstration of anti-Stokes cooling of
a small sample of BaY2F8 (BaYF) single crystals doped with Yb (2.5%) grown in
the University of Pisa laboratory.
The experiment consisted of measuring the cool down of the crystal over time
(~50 minutes) while it was being pumped by 3W of 1025 nm CW light from laser
diodes. The steady-state cooling achieved was 4K at room temperature.
The experiment has been successful. The next key issue is to develop a detailed
plan of how this idea can be actually implemented in a suspended interferometer
in order to reduce thermal noise of fibres.
Improvement Q measuring facility Perugia
A close collaboration, as STAC previously suggested, was set up
between Perugia and LMA-Lyon on the measurement apparatus
delivered to Lyon. The positive results are clear from both the Perugia and
Lyon reports of progress.
Progress has been made in improving the sensitivity of the instrument at
Perugia which has as its goal the direct measurement of the thermal
noise. The sensitivity of the instrument is now sufficient to measure the
peaks of the thermally-excited resonances in the test piece, and the use of
the instrument to characterize a series of coatings can now start.
Thermal Noise at Cryogenic Temperatures INFN-Pisa et al.,EGO
The cryogenic facility is growing properly.
The laboratory space at EGO is completed and the large cryostat is
expected to be delivered at EGO in a few weeks time.
It is designed to house a full last stage of Virgo-kind suspension with a full
Everything seems in schedule and no major problems are foreseen, apart
from the fact that no Company with the necessary experience to produce
monolithic Si strips at reasonable price has been found so far. This could
become a problem along the research line on the use of pure Si as mirror
Fused Silica Suspensions Perugia
The research group reports completion of a fused silica wire production
facility in Perugia. They validated the wire production procedure.
The facility is now in production mode that is fully automated and stable.
It is possible to set a fibre diameter and the computer selects the pulling
speed to drive the machine. They are able to produce custom designed
fibres with variable diameters from 10 - 400 microns. The group
successfully developed and delivered an OH flame based fibre pulling
The machine is currently under installation at EGO in the new laboratory
there created to house both the fibre pulling techniques and the
They also validated the silicate bonding procedure and have transferred
knowledge about the technique to the EGO staff at Cascina.
CO2 laser for monolithic suspensions Glasgow
Good progress was made on the development of the CO2 laser fibre
pulling and welding machine. A simple machine with a fixed feed-pull
speed ratio was tested and used to produce ribbons (5-9mm wide and
100mm-300mm thick) and fibres (15mm-18mm diameter). The power
stability of the CO2 laser was improved to get better control on the width
and thickness of the ribbons.
Components for the first version of the more complicated pulling machine
are on order and the test of the first prototype is expected to start soon.
The performance of that prototype will give a good indication on the
overall progress made in this project.
Its deliver at EGO is expected in early spring 2006
Signal re-cycling LAL
The Orsay LAL group works together with groups in LIGO on the
development of simulation tools for a dual recycled interferometer and on
the commissioning of the 40m Caltech prototype in its dual recycled
configuration. The proposed work for the next period is side-band phase
noise propagation, radiation pressure effects, higher order modes,
implementation into SIESTA.
STAC suggested to put high priority on the validation of the simulation with
experimental results wherever possible.
Data analysis ILGA-Cardiff
Spinning binary black holes
A new postdoc was engaged (Nov 2004) at Cardiff for this effort. Her
first efforts (April 2005) have been to „get up to speed‟ in the field; new
work has led to developing a code to compute the waveform from a
pair of spinning binary black holes. This is still in development and
testing. The objective remains to develop templates which cover the
additional variable of the black hole spins, a quite necessary
Control System upgrade Annecy-LAPP, Pisa, EGO
-Task 1 - DSP (Pisa, EGO). 6U VME Carrier board hosting a PC/104Plus CPU module
with Fast Ethernet and Linux OS, a mezzanine board with up to 6 DSPs and a
mezzanine board for timing and optical link interface. Prototypes are in construction;
tests in course.
-Task 2 and 3 – (LAPP) TOLM (Timing and Optical Link mezzanine) - Good progress
with extensive test of the digital optical link and start of development of interface
programs have been reported.
-Task 4 - ADC (LAPP). Improved differential interface modules with programmable
filter for the existing ADC boards: 30 boards (60 channels) ready for tests by May.
The new ADC board will integrate such new features after tests.
-Task 5 - New DAC/Coil driver (Pisa, EGO) Conceptual design ready. A prototype has
been tested smoothly.
-Task 6 - New demodulation board (LAPP). No progress reported as yet.
-Task 7 - New detection electronics at higher modulation frequency (LAPP). No
progress reported as yet.
-Overall, the activities are progressing quite well.
-Most activities at Pisa are reportedly focused on the DSP board. However, progress
has been made also on the development of the new DAC (Task 5).
-It is advisable that a detailed prioritized plan for the swap of the new electronic
boards and modules is agreed with Virgo and prepared.
Modeling Thermal Noise Perugia and Florence-Urbino
The collaboration set up, tested and shared a simulation environment,
with ANSYS, to model thermal noise in mirrors and mirror suspensions.
Then Perugia dedicated to model the VIRGO mirrors, to a simulation of
substrate+suspension wires+multilayer coating (taken from F/U
results)+silicate bond , and made comparisons between the outcome of
the model and relevant quantities, as mirror modes frequencies and
quality factors, measured during the Virgo Commissioning runs. Results
are satisfactory for frequencies, while for quality factors indicate that
thermo-elastic losses should be taken in account.
Then Florence/Urbino dedicated to silicon fibres, to include soon
thermoelastic effects, and to methods for a fruitful modelisation of
coatings, with aim to extract relevant parameters as the loss angle.
Spherical Resonator Roma Tor Vergata
The objective of the research is to demonstrate the feasibility of ultra-cryogenic
The scheduled milestone is to start data taking of MiniGrail, a solid sphere copper-
aluminium detector with a mass of about 1 ton at the end of the second year. At
the first run, the noise spectrum was taken and compared with the full electro-
mechanical numerical model. The noise temperature was 70 mK and eight thermal
peaks were identified without any unexpected resonances and spurious noise.
The observation by resonant antennae makes up for less sensitive frequency
band by laser interferometers. The R&D of resonant antennae is of benefit also to
cryogenic interferometers. Therefore, the importance of the R&D of resonant
antennae does not reduce even though interferometric detectors attain better
sensitivity at around 100 Hz. Also good point of the R&D of the resonant antennae
is the cost effectiveness of the experiments, which makes small experimental
groups enter this field. They may supply future good scientists working on
gravitational wave research.
Wide band transducer (Dual Torus) Padova
The objective of the research is to investigate the noise characteristic of the
proposed wideband mechanical amplifier for the dual cylindrical detector.
The mechanical amplifier realizes noise matching between a massive resonant
antenna and a sensitive displacement sensor to produce optimised signal. The
target is in three years to measure thermal noise of the mechanical amplifier at
room temperature and to investigate contributed noises at a level of thermal
noise. For this target, a mechanical amplifier prototype was designed and
successfully analysed by ANSYS in the first year. And in the second year, its
transfer function has been measured with a test oscillator.
The research is only a part of the development of the dual cylindrical detector
and the final result of this research will be tested in the future. However, STAC
supports the activity of this group by the same reason as for 'Spherical
Quantum noise LKB/ARTEMIS
This experiment, with the objective to study both theoretically and
experimentally the quantum noise in gravitational wave interferometers,
continues to progress well. It is a collaboration of the Paris-LKB and Nice-
ARTEMIS laboratories, and both sides are contributing to the effort.
Recent progress involves the fabrication of a higher-finesse cavity, using
mirrors coated by LMA; a finesse of 230 000 has been realized. An
improvement in the frequency stabilization has been made.
Improvement of coatings Q and
Corrective coatings LMA
1. Improvement of coatings Q LMA-Lyon
The report gives a clear and helpful description of the ringdown apparatus built by
Perugia and with modifications by Lyon. Following the STAC
recommendations of Fall 2004, a much stronger collaborative effort has been
pursued, and the result is that the apparatus is now fully functional and
capable of making measurements which can discriminate at the required level.
The objective of the research has been met: Now it is possible to make a
coating run and then, without removing the sample from the clean room where
the coating was made, a definitive characterization of the mechanical loss of
the coating undertaken.
2. Corrective coatings LMA-Lyon
The first three mirrors with Mexican Hat produced so far have been sent to
Caltech for testing, to better learn about their appropriate construction
procedure. A first simulation of the mirrors has been done and it looks rather
promising. The project, globally, sounds good.
Hollow Fibers ILGA
Nice concentrated their R&D activities on studying the use of fibres as
mode cleaners, activity encouraged by the STAC. They first positively
checked the possibility of efficient laser-fibre coupling. Other tests showed
that fibres do not add significant to frequency noise and at high frequency
to amplitude noise. Problems with low frequency noise do not seem to be
serious. Polarization noise is under study but in any case existing fibres
do not preserve polarization. Collaboration with Limoges began on
improving fibre quality (existing fibres are not single-mode).
Also fibre end are very sensitive to dust. Various solutions of this problem
are under study.
Interferometer Optimization Nice and ESPCI
The R&D program consists in upgrading the two simulation codes and
software systems developed in Nice and at ESPCI and in comparing the
results of the codes. The Nice code has been upgraded and made more
user friendly. First comparison between the Nice (DARKF) and ESPCI
(NV) codes have been performed pointing towards bugs that have been
corrected. Preliminary studies of a flat mode interferometer are also on
their way and turn out to be promising.
Absorption at 1.5 micron of Si ESPCI
With their own CW laser, they have found a minimum
absorption of 40 ppm/cm for slightly doped silicon crystals (P
and N, with resistivity of the order of 1000 Ohm.cm). For
VIRGO at low temperature (77 K and below) this is already
better than silica for the thermal point of view (thermal lens
With the new laser provided byEGO the density of power in
their experiment is about 40 GW/m2 (30 W peak power
focused on a 30 micron spot) and, even with a new
generation of antenna with a 1 kW source and an order of 1
MW in the arm, the density of power in VIRGO will be
around 0.1 GW/m2. This will induce an extra absorption of a
few hundredth ppm which is negligible. 22
The VESF fellowship program
In Autumn 2004, in the framework of its R&D program, and in support of the Virgo-
EGO Scientific Forum, VESF, EGO launched a program of fellowships open to
European groups working on theory of gravitation interested in dedicating work to the
sources of gravitational waves that may fall within the observational reach of Virgo and
its possible upgrading.
These fellowships were for up to 10 man-years for 2005 and for 2006 (and similar
amounts for the following years, subject to the availability of funds).
The durations of the fellowships was intended to be from a month to two years. The great
majority are two-years.
It was expected that fellowship holders would come periodically to EGO to illustrate the
advancements of their work.
9 Conventions were drawn with groups of 4 European Countries: France, Greece, Italy,
The approved VESF fellowship bi-annual program 2005-2006
University of Alicante, Dpto. Fisica Aplicada, Probing general relativity and nuclear physics with
Spain gravitational waves from newly born neutron stars
Aristotle University of Thessaloniki, Department Non-linear oscillations of compact stars and gravitational
of Physics, Greece waves, synergy between the non-linear perturbation methods
and numerical relativity.
Institut Henri Poincare , Paris 3-month program on General Relativity, Gravitational Waves,
Relativistic Astrophysics and Cosmology
LAL (Orsay)+IAP (Paris)+Cardiff Post-newtonian theoretical study of compact binary sources
Istituto Astrofisica Spaziale e fisica Cosmica of Gravitational Waves by Gamma-Ray bursts
CNR , Rome
Physics Dept., University of Rome La Sapienza Study of the r-modes instabilities in rotating neutron stars
SISSA/ISAS, International School for Advanced Gravitational-waves Emission from Mixed Binary Systems
Studies, Trieste, and Oxford
Universita' degli Studi di Trento - Dipartimento di Gravitational wave search with the operating network of
Fisica interferometers and resonant detectors
Physics Dept., Pisa University Stellar evolution of progenitor systems and Analysis of local
Galactic sources for stochastic background
Universitat de Valencia, Spain Numerical General Relativistic magneto-hydrodynamics
simulation of accretion discs as GW sources
Future call for R&D proposals
The STAC – the EGO Scientific and Technical Advisory Committee - recommended that
a White paper on R&D be completed by the Virgo collaboration in a timely way to be
made available as part of the next call for proposals for research.
The next STAC meeting, in the middle of October, is expected to give suggestions on the
general targets for a new call for proposals in R&D.
The STAC recommended already that the Fellowships be used creatively to draw groups
to the Observatory, and engage them in a mix of commissioning, data analysis, and
research targeting future developments.
At the VESF executive board of last 2 September it was considered important to open a
new a new call for proposals for a few fellowships in theoretical and DA studies.
The EGO Council next November will decide on the when, how and how much for the
development of EGO R&D program.