Study of Thermal Noise Reduction for European Gravitational Wave Detectors STREGA

Transcription

1 Joint Research Activities JRA3 Study of Thermal Noise Reduction for European Gravitational Wave Detectors STREGA REQUESTED BUDGET: 1390 k DURATION: 5 years

2 Joint Research Activities Proposal full title Proposal acronym Study of Thermal Noise Reduction for European Gravitational Wave Detectors JRA3 STREGA Role Name Lab address Coordinator Karsten Danzmann MPI Hannover Deputy Contact Persons Gianpierto Cagnoli Raffaele Flaminio University of Glasgow LAPP Annecy Interconnected with: A1 N2 N3 N4 N5 N6 JRA 1 X JRA 2 JRA 3 ABSTRACT : The observation of gravitational waves will open a new window on the Universe. Current detectors are designed to achieve the first direct detections and their proposed upgrades will allow detection of typical sources at distances of up to 100 Mpc. For effective Gravitational Wave Astronomy the sensitivity of future advanced detectors must increase ten-fold. The main noise limitation to the current and upgraded detectors is internal thermal noise in the test masses. The main objective of this proposal is to produce a ten-fold reduction of the internal thermal noise level in future detectors. In Europe there are two interferometric detectors, GEO600 and VIRGO, and three resonant detectors, AURIGA, EXPLORER and NAUTILUS, all at different stages of upgrade. In the U.S. there is the LIGO Project, which consists of three interferometric detectors in two locations, and the resonant detector ALLEGRO. The LIGO Project is proposing to undertake a major upgrade of all three detectors pushing the detection distance up to 200 Mpc. In Japan the interferometric detector TAMA is operating and significant effort is being spent on the development of a cryogenic detector. Australia contributes to the international scenario with the AIGO Project, which is currently developing a high power prototype. To date the collaboration between the various European projects has been good due to significant overlap of objectives. The joint challenge presented by this ten-fold reduction of thermal noise requires increased focusing of research effort from the European collaborators drawing on all of the expertise acquired to date. In the future, the research structure developed by this JRA will continue with the aim of designing and building an array of European advanced detectors. The main deliverables of this JRA are: i) design, construction and testing of final stage prototypes for advanced interferometers and test masses for resonant detectors; ii) development of advanced electromechanical, optical and super conductive transducers; iii) facility for the investigation of the mechanical effects of cosmic ray absorption in test masses; iv) development of cryogenic suspensions for interferometers and resonant spheres; v) facilities for direct thermal noise measurements.

3 Table 1a - Participants (Contractors) Participant # Organisation (name, city) Country Short name 3 INFN, Roma Italy INFN IFN CNR- ITC, Trento IN2P3 - CNRS, Paris University of Leiden University of Glasgow Italy France Nether -lands U.K. IFN CNRS MiniG RAIL IGR Short description (i.e. fields of excellence) Design, construction and operation of the resonant cryogenic detectors AURIGA EXPLORER and NAUTILUS and development of advanced resonant detectors and transducers. Design and construction of detectors based on superconductive RF cavities. Design, construction and operation of the detector VIRGO and development of advanced interferometric detectors. Selective readout simulation, FEM, low loss matching networks for SQUID amplifiers. WP-M2: investigation of some advanced materials for resonant detector test masses; WP-T3: development of selective read-out for resonant detectors. Metrology tools for optical measurements. Theoretical and experimental studies of thermal noise. Development and characterization of large dielectric coatings. Development of optical configuration and locking schemas for advanced interferometric detectors. Design and construction of the spherical cryogenic detector MiniGRAIL and R&D on advanced resonant detectors. WP-M1: low temperature characterization of mirror substrates; WP-M2: investigation of some advanced materials for resonant detector test masses; WP-M4: cryogenic system for dielectric loss measurement facility; WP-M5: cryogenic system for suspension loss measurement facility; WP-C1: thermal conduction investigation of final stage suspension; WP-C2: development and construction of advanced cryogenic system for resonant detectors; WP-T1: investigation of the thermo-elastic noise at low temperature; Design and construction of the interferometric detector GEO600 and R&D on advanced detectors. WP-M1: low temperature Q measurements of some advanced materials for mirror substrates; WP-M2: investigation of some advanced materials for resonant detectors test masses; WP-M4: investigation of mechanical losses of dielectric coatings; WP-M5: low temperature Q measurements of some advanced materials for mirror suspensions; WP-T1: modification of a test facility for the direct measurement of thermal noise; WP-T2: investigation of the photo-elastic noise at low temperature Contribution man X months Updated : 15 Apr. 04 Part B: 3 / 32 Pages /

4 Table 1b - Associated Participants Organisation (name, city) INFN Sez. Ferrara; INFN Sez. Firenze & Urbino; LENS, Firenze; INOA, Firenze; INFN Sez. Genova; LNF, Frascati; LNL, Legnaro; INFN Sez. Napoli; INFN Sez. Padova; INFN Sez. Perugia; INFN Sez. Pisa; INFN Gr.Coll. di Trento Sez. Padova; INFN Sez. Roma 1; INFN Sez. Roma 2; INFN Sez. Urbino; Country Italy Short name INFN Short description (i.e. fields of excellence) Design, construction and operation of the resonant cryogenic detectors AURIGA EXPLORER and NAUTILUS and development of advanced resonant detectors and transducers. Design and construction of detectors based on superconductive RF cavities. Design, construction and operation of the detector VIRGO and development of advanced interferometric detectors. WP-M1: investigation of advanced materials for mirror substrates; WP-M2: investigation of advanced materials for resonant detector test masses; WP-M3: full investigation of Niobium superconductive state; WP-M4: investigation of mechanical losses of dielectric coatings for optical transducers; WP-M5: characterization of suspension materials for resonant detectors; WP-M6: full investigation and facility modification for cosmic ray induced acoustic emission; WP-C1: design and construction of a final stage suspensions for interferometers; WP-C2: development of cooling technology for advanced resonant detectors; WP-C3: development and construction of advanced cryogenic system for interferometers; WP-T1: investigation of thermo-elastic noise at low temperature; WP-T2: direct measurement of the photo-elastic noise at low temperature; WP-T3: development of selective read-out for resonant detectors. Contribution man X months See table 1a CNRS, Paris ESPCI, Paris LKB, Paris; LAL, Orsay SMA, Lyon France CNRS Metrology tools for optical measurements. Theoretical and experimental studies of thermal noise. Development and characterization of large dielectric coatings. Development of optical configuration and locking schemas for advanced interferometric detectors. WP-M1: investigation of the optical properties of CaF 2, YAG and Silicon; WP-M4: production of dielectric coatings with low mechanical losses and development of new tool for optical measurements; WP-T1: theoretical investigation of the thermo-elastic noise at low temperature and direct measurement; WP-T2: production of dielectric coatings with low optical losses and optical absorption measurements; theoretical investigation of light absorption effects of coatings at low temperature; WP-T3: development of selective read-out for resonant detectors. See Table 1a Updated : 15 Apr. 04 Part B: 4 / 32 Pages /

5 JRA3 Activity Number Work Package 1 WP-M1 Work Package 2 WP-M2 Work Package 3 WP-M3 Work Package 4 WP-M4 Descriptive Title Advanced materials for mirrors substrates Advanced materials and techniques for resonant detectors Investigation on superconducting materials Development of low loss dielectric coatings for advanced detectors Table 2 - Activities Short description and specific objectives of the activity Silicon (Si) and Calcium Fluoride (CaF 2 ) have been considered the best candidates as mirror substrates for advanced interferometers. In this task thermal expansion, thermal conduction and mechanical losses of these two materials will be measured, varying the temperature from 300K down to 4K. In case of silicon, the alteration of thermo-mechanical properties as a function of quantity and nature of dopants is investigated. Prototypes will be realized and tested in connection with the tasks M4 and M5 High-performance materials can increase the sensitivity and bandwidth of resonant detectors to achieve the intended 10-fold increase in the detection capabilities. This task aims to develop knowledge of the material properties and innovative technology for the production of test masses and transducers made of these new materials. The selected materials are Molybdenum, Silicon-Carbide (SiC), Beryllium, Copper Aluminium (CuAl), Niobium. Thermal expansion, thermal conduction and mechanical losses will be measured varying the temperature from 300K down to 0.1K. Fabrication processes to be investigated are silicate bonding for SiC, and electron beam welding, explosion welding and cold welding for metals. In order to reduce the cool-down time, an investigation will be carried out on the various metal production processes as well as low temperature calorimetric studies to choose metals with the smallest Hydrogen contamination. An innovative detector based on superconducting resonant cavities has recently been proposed. The interesting feature of this detection scheme is the very high electromagnetic quality factor that can be obtained in superconducting structures. It is proposed to build cavities using the technique of niobium sputtering on a substrate having high thermal conductivity and low intrinsic mechanical dissipations. Such a facility will be essential for the development of advanced superconducting RF detectors with high sensitivity. Dielectric coatings are used by all kinds of detectors and may severely limit the performance of detectors. It is proposed to develop an innovative technology for low loss dielectric coatings, starting from an investigation of the specific loss reduction of SiO 2 /Ta 2 O 5. and SiO 2 /Al 2 O 3. Another possibility is to decrease the number of layers and investigation on SiO 2 /XX, where XX is a high index of refraction material like Zinc Selenide (ZnSe), are considered here. Measurement of mechanical losses, optical losses and index of refraction have to be performed at room and low temperatures. Prototypes will be realized and tested in connection with the tasks M1 and M5. Updated : 15 Apr. 04 Part B: 5 / 32 Pages /

6 JRA3 Activity Number Work Package 5 WP-M5 Work Package 6 WP-M6 Work Package 7 WP-C1 Work Package 8 WP-C2 Descriptive Title Innovative materials for advanced detectors suspension Study of thermo elastic effects caused by absorption of cosmic rays Cryogenic Last Stage Suspension Cryogenic suspension system for advanced resonant detectors Joint Research Activities JRA3 STREGA Short description and specific objectives of the activity An investigation of low temperature properties of and fabrication processes for fibres made of Silicon, Calcium Fluoride, Molybdenum and Ruthenium is planned. These materials have excellent low temperature properties and they are compatible with the mirror and test mass materials developed in WP-M1 and WP-M2. A very innovative technology that has to be fully investigated is based on a localized cooling process through the inverse fluorescence mechanism. In this case a novel technology for the fabrication and doping of fibres made of YAG, CNGG [Ca 3 Nb 2 Ga 3 O 12 ] and NLW [NaLa(WO 4 ) 2 ] will be developed and the material properties investigated. Prototypes will be realized and tested in connection with the tasks M1 and M4. In a low temperature detector the energy released by cosmic rays represents a significant contribution to the thermal energy of the test masses. In addition to the increase in the average energy in the test masses, the absorption of cosmic rays produces bursts of acoustic emission through a thermoelastic process that could be confused with gravitational wave bursts by the detector. A theoretical investigation of the thermoelastic mechanism that generates the acoustic emission and a series of tests on different materials are proposed. In more detail, the tests will be performed at low temperature and the acoustic emission, induced by particles accelerated by a machine, is detected by mechanical or optical transducers. This part of the suspension system close to the optics has been called final stage and deserves special care since it is relevant for the overall thermal noise performance. In cryogenic detectors the final stage ought to provide a good thermal conduction and at the same time it has to satisfy the thermal noise requirements. This goal can be achieved through the investigation of suitable materials (task M5) as well as through the design of new suspension elements (such as cantilever blades or flexural joints) to be located on the final stage. A low noise remote control of the mirror position has to be achieved, using sensors and actuators compatible with the cryogenic environment. A full prototype of cryogenic final stage will be assembled and tested. The double task of removing the heat from the antenna resonator while keeping it mechanically isolated from the environment is similar to the one that will be encountered in the cooling of the interferometer mirrors. Although the ultra cryogenic detectors have been successfully operated, further advances in cooling and/or isolating the antenna can be achieved via finite element modelling and experimental tests. Two 1.2 ton spheres with their cryogenic suspension will be assembled and measurements of mechanical quality factor and thermal noise at low temperatures performed. Updated : 15 Apr. 04 Part B: 6 / 32 Pages /

7 JRA3 Activity Number Work Package 9 WP-C3 Work Package 10 WP-T1 Work Package 11 WP-T2 Work Package 12 WP-T3 Descriptive Title Cryogenic suspension system for interferometers Set-up of a facility for the measurement of thermo-elastic noise Direct measurement of the photo-elastic noise Development of selective readout schemes Joint Research Activities JRA3 STREGA Short description and specific objectives of the activity The aim is to demonstrate the capacity to remove a sufficient amount of heat from the cryogenic payload while preserving the suspension seismic isolation performance, namely its softness in all degrees of freedom. This result can be achieved by connecting suspension attenuation stages with high compliance and high thermal conductivity elements, exhibiting, at the same time, low stiffness. The entire apparatus will be located in a cryogenic environment; the extra noise coming from the cryogenic system has to be studied and reduced to negligible values. A full cryogenic suspension will be assembled and tested. Using a very high sensitivity interferometer with a small spot size on the optical elements it should be possible to observe the thermo-elastic noise in sapphire, YAG, Silicon and CaF 2 masses. Some existing facilities like the interferometers in Glasgow and in Perugia have to be converted and upgraded. After this substantial change has been completed, then the possibility of the direct measurement of thermo-elastic noise will be investigated. Theories on thermal conduction inside mirrors and coatings can be experimentally verified using the photo-elastic effect induced by a low frequency intensity modulation of the light entering a Fabry- Perot cavity. This measurement can be performed with the temperature ranging between tenths of Kelvin up to room temperature. Low optical loss coatings will be tested. The effect of thermal noise depends on the size of the read-out area that in case of the interferometers is determined by the laser spot on the mirrors whereas in case of the resonant masses is determined by the displacement transducer used. The study of read-out configurations, in which only the contributions coming from modes strongly coupled to the signal of interest are selected, is proposed. At this end developments on the Fabry-Perot cavities, on RF superconducting cavities and on capacitive transducers are implemented Updated : 15 Apr. 04 Part B: 7 / 32 Pages /

8 Table 3 - Summary table of expected budget and Community contribution requested Participants (as listed in Table 1a) Project Participant # Amount (euro) exp. budget req. contrib Exp. Budget req. contrib exp. budget req. contrib exp. Budget req. contrib exp. budget req. contrib Total expected budget ( ) Max Community contribution requested ( ) JRA Updated : 15 Apr. 04 Part B: 8 / 32 Pages /

9 II DESCRIPTION OF THE JRA3 ACTIVITY 1. SCIENTIFIC AND TECHNOLOGICAL EXCELLENCE 1.1 Objectives and originality of JRA Objectives & originality A) GRAVITATIONAL WAVES: A NEW WINDOW ON THE UNIVERSE Einstein s theory of gravitation, General Relativity, predicts the existence of gravitational waves (g.w.). Quantitative analyses of experimental data obtained from observations of binary star systems, and in particular binary pulsars such as that discovered by Hulse and Taylor, give strong evidence that these systems do in fact lose energy through gravitational radiation. For an ever growing number of scientists the direct detection of g.w. is taking on the dimensions of a challenge to be met with top priority. Indeed, it offers an approach to understanding fundamental frontier physics by testing relativistic gravitation theories, directly studying systems where gravitation acts in its fully strong regime, observing processes in which - uniquely - gravitation overcomes nuclear and sub-nuclear interactions, thus opening the way to the direct observation of dynamics of cosmic bodies in an universe whose structure and evolution is in fact governed by gravitation. In recent years the scientific community has boosted the effort on detecting gravitational waves by building several detectors based on laser interferometry. Soon this new technology will be as reliable as the one based on resonant bars, which at the moment can count on 5 fully operational detectors, 3 of which (plus one in construction) are in Europe. Now that the first generation of long baseline gravitational wave detectors is commencing operation there is an urgent need to look to the future. The initial experiments represent a huge increase in sensitivity beyond any previous systems, reaching for the first time levels where it is possible to detect strong supernovae in the Virgo cluster and coalescing black holes out to a distance of about 150 Mpc. Nevertheless, no more than a few such events can be expected during the operation of the initial network. Higher sensitivities will be required before real astronomy can begin, but the present projects are so far only funded to reach their initial sensitivity goals. This situation is greatly improved with the detectors of the new generation that are being designed for both the two technologies now available. Conservative estimates predict an event rate of a few per year for the NS/NS coalescence. The detection of a cosmological gravitational wave background becomes a realistic possibility. In order to achieve these results, giving the possibility to the scientific community in Europe to maintain the leading position in this field, a joint effort among several groups in Europe is proposed. B) STRATEGIC PLAN FOR THE FUTURE GRAVITATIONAL WAVES OBSERVATORIES Detectors of two kinds are being developed towards ultimate efficiency, so far separately, namely ultracryogenic resonant bars and spheres and wide-band, km-baseline, interferometers. A third class of detectors based on parametric resonance of two weakly coupled superconducting Radio- Frequency cavities has been developed and recently a first prototype has been realized. All these three complementary kinds of detectors cover the low (few Hz to few hundred), the intermediate Updated : 15 Apr. 04 Part B: 9 / 32 Pages /

10 (few khz) and the high frequency (up to few GHz) ranges of detection achievable for Earth based detectors. Major advances in the physics and technology of the related areas have already been achieved and further advances are needed and indeed expected. The integration between these detectors is becoming a reality after the people involved in the design of future interferometers started to be interested in low temperature and at the same time the people working on resonant detectors started to develop interferometric readouts for their systems. Still the collaboration is fragmented and sporadic. In the laboratory reference frame, the gravitational waves generate a force proportional to the mass of the body and to the distance of this body from the origin of the reference frame. In the resonant detectors this force may excite the normal modes of the test mass, depending on the frequency of the wave and the mechanical response of the mass. In the interferometers the gravitational wave force changes the distance of the optical components creating a signature in the interferometric pattern. In case of the RF cavities, the weak electromagnetic coupling between them generates the two modes (symmetric and anti-symmetric on the fields); a gravitational wave force deforms the cavities and if this repetitive action matches the frequency difference between the two modes, then a transfer of energy between these two modes occurs. This energy transfer is carefully detected. This short description of the detection principles should make clear that in all the detectors the effect of the gravitational waves is mechanical, therefore an inherent and ultimate detection limit for all the detectors is given by the thermal noise that causes a random fluctuation of shapes and positions of the test masses. Thermal noise is the dominant noise source in the resonant and RF cavities detectors and the major limit to the detection in the central frequency band 10 Hz to few hundred Hz for the interferometers. In order to be sensitive to signals coming from events at cosmological distances, the future detectors must have the thermal noise reduced by at least a factor of ten with respect to the best detector achievable today with the current technology. A joint research project on the thermal noise reduction can exploit the potential of the complementary expertise in materials, optics, and cryogenics acquired separately over the years in a number of laboratories. Development of new technologies as described in this proposal will allow the future detectors to increase their capabilities significantly over the frequency range between few Hz and few GHz. With respect to the USA and Japan, the best chance for European countries to take the crucial step forward on their own R&D track and take a leading position in future observations is to support and organize a collaborative effort in a joint research project Current State of the Art and Feasibility The 5 resonant detectors already built (3 in Europe, 1 in USA and 1 in Australia) operate in the 0.1K to 5K temperature range and the materials used are Aluminium 5056 and Niobium. All of them are in the shape of a cylinder about 3 metres in length and 2000 kg in mass. Limits to the detection are given by the relatively high mechanical dissipation (high thermal noise) of the materials used and by the narrow bandwidth of the detectors. So far technological problems have dictated the shape and the materials of the resonant elements. The detection range of a NS/NS coalescing binary will increase from the present 50 kpc (Galactic range) to hundreds of Mpc if the fabrication processes for new materials with innovative shapes (dual spheres and cylinders) and the implementation of new read-out configurations as described in this project are used in the advanced resonant detectors. Updated : 15 Apr. 04 Part B: 10 / 32 Pages /

11 All the 5 interferometric detectors that are at different stages of operation (2 in Europe, 2 in USA and 1 in Japan), and the one in Australia that is still in the design stage, work at room temperature. The optics are made of high grade silica and all the detectors use steel suspensions, apart from GEO600 which uses monolithic silica suspensions, a technology that will be implemented in the other detectors in their upgrading plans. All these detectors are designed to search for NS/NS coalescing binaries in the few tens of Mpc range. A design study for the advanced American detectors (LIGO) that aims to exploit the room temperature technology as much as possible foresees a detection range of about 200 Mpc. Key points of this study are the monolithic silica suspensions and the sapphire optics. Completion date for the Advanced LIGO is The new detection method based on Super Conducting Radio Frequency cavities has to be further developed in order to realize a fully operational gravitational wave detector. So far small size experiments have already proven the feasibility of such a method. The SCRF cavities may be used as transducer elements in the resonant detectors and in the selective read-out schemas as well. 1.2 Implementation plan of the joint research activity Multi-annual implementation plan for the I3 whole duration & by tasks The present JRA STREGA has three main objectives: 1) Investigation of Materials for Future Detectors; 2) Design of Advanced Cryogenic Suspensions; 3) Study of Thermo and Photo Elastic Effect. Each of these objectives has been divided in tasks, 12 in total, described in Table 2. Each task is identified by a code: M1 to M6 for the tasks regarding the investigation of advanced materials; C1 to C3 for the cryogenic suspension development; T1 to T3 for the ones regarding the thermo and photo elastic noise study. Table 4 shows in a schematic form the 5 year implementation of the activity plan for each task. During the execution of the plan it may happen that the items are revised as a result of advances in that particular field. The revision of the plan is one of the main points of discussion at each annual general meeting of STREGA. A detailed plan for the first 18 months is presented on Table 5. Updated : 15 Apr. 04 Part B: 11 / 32 Pages /

12 Meas. at room temp. on Si and CaF2 Meas. at low temp. on Si and CaF2 Investigation on the doping effect on Si Investigation on silicate bonding at low temp. Optical measurements on Si and CaF2 Prototypes Design and Build (*) Writing up of the final report alpha, k and Q meas. at low temperature Construction and test of resonators in CuAl, SiC and Be Improving fabrication processes Investigation of Q at lowest achievable frequencies Test of a metallic trans. on a resonant sphere Upgrade of suspension performance of test facilities Test on CuAl and SiC trans. at room and low temp. Investigation of mech. losses after chemical treatments Construction of optical and superconducting transducers Limiting bias electric fields in the capacitive transducer Effect of the dielectric coating on the thermal noise Design, build and test prototypes Writing up of the final report Cavity Design and Mock-Up measurements Production of seamless copper cavities Niobium Sputtering Optimisation Mechanical qualification of substrata Prototype Build and Measurement Writing up of the final report Production of substrates and coatings Development of diffractive coatings Meas. at room temp. on different coatings Losses investigation at low temp on: SiO2/Ta2O5 : SiO2/Al2O3 : SiO2/high n : diffractive coatings Optical measurement at room and low temp Prototypes Design and Build (*) Writing up of the final report Joint Research Activities JRA3 STREGA Table 4 : Multi-annual implementation plan of the JRA3 Activity YEAR 1 YEAR 2 YEAR3 YEAR 4 YEAR 5 Sub-Tasks Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q TASK 1: Advanced materials for mirrors substrates (M1) Task 2: Advanced materials and techniques for resonant detectors (M2) Task 3: Investigation on superconducting materials (M3) Task 4: Development of low loss dielectric coatings for advanced detectors (M4) Updated : 15 Apr. 04 Part B: 12 / 32 Pages /

13 Mechanical and Q measurements on Si, YAG, Mo, Ru fibres Production of monocrystalline fibres Mechanical and Q measurements on monocrystalline fibres Local cooling on monocrystal fibres Design and realization of full scale prototypes (*) Writing up of the final report Room temp. acoustic measurements on Al Low temp. acoustic measurements on Al and Si Low temp. acoustic meas. on Cu and other materials Studying of acou. emission induced by part. absorption Writing up of the final report Low temperature accelerometer design and build Installation and performance test of Pulse Tube Refr. Modification of Rome cryogenic facility hosting PTR Measurements of noise performance of PTR Installation and testing of the prototype Writing up of the final report Cooling of a spherical detector to 50 mk Inst. and test of a PTR on the spherical det. MiniGRAIL Noise measurement and tuning of suspensions Test of a sphere with a resonant transducer Optimisation of the read-out and double SQUID Brownian noise measurement Detector operation and data taking Writing up of the final report Development of payload finite element model Cryo payload Prototype: Design and Build Design and Build of new super-attenuator Installation and test of cryo facility in Cascina Writing up of the final report Direct Th. Noise meas. facility modification Direct Th. Noise meas. on Si membranes Improvement of the ref. cavities noise performance Direct Th.elastic Noise meas. on suspended crystals Writing up of the final report Task 5: Innovative materials for advanced detectors suspension (M5) Task 6: Study of thermo-elastic effects caused by absorption of cosmic rays (M6) Task 7: Cryogenic Final Stage Suspension (C1) Task 8: Cryogenic suspension system for advanced resonant detectors (C2) Task 9: Cryogenic suspension system for interferometers (C3) Task 10: Set-up of a facility for the measurement of thermo-elastic noise (T1) Updated : 15 Apr. 04 Part B: 13 / 32 Pages /

14 Room temp. meas. on: waist dependence of th-el noise : different mirror substrates and coatings Test and set-up of high finesse cavities at low temp. Dynamic photo-therm. effect meas. at low temp. Writing up of the final report Task 11: Direct measurement of the photo-elastic noise (T2) Task 12: Development of selective read-out schemes (T3) Development of the folded Fabry-Perot cavity Development of concave-convex cavities at room temp. Test of concave-convex cavities at low temp. Noise evaluation of "Dual" det. with selective and wide area detection Test of a selective read-out scheme to a wide area cap. trans. Wide area read-out using r.f. superconducting cavities Writing up of the final report (*) The prototypes consist of final stage suspensions. The integration of the tasks M1, M4 and M5 is needed. Joint Research Activities JRA3 STREGA Updated : 15 Apr. 04 Part B: 14 / 32 Pages /

15 Detailed first 18 months implementation Table 5 - Temporal development of the project tasks over the first eighteen months TASK 6 Months 12 Months 18 Months 1 Materials for mirrors Room temperature measurements of Q for Si and CaF2 masses Thermal expansion and Q measurements at 4K of Si and CaF2 masses Q measurement of Si and CaF2 masses at variable temperature between 4K and 130K 2 Materials for resonant detectors Construction of CuAl, SiC and Be resonators Construction of optical and superconductive capacitive transducers Test of CuAl and SiC transducers on an Aluminium antenna Surface loss measurements after chemical treatment Coating losses measurements at low temperature Niobium sputtering losses measurements at low temperature Experiments on limiting bias electric fields in the capacitive transducer 3 Superconducting materials 4 Dielectric coatings 5 Materials for Final Stage Suspension 6 Cosmic rays absorption 7 Cryogenic Final Stage Suspension Q and α measurements on the materials CuAl, SiC and Be between 0.1K and 4K Loss property of silicate bonding on SiC at low temperature Realization of an RF cavity with substrate of copper and internal coating of sputtered niobium Production of the first SiO 2 /Ta 2 O 5 and SiO 2 /Al 2 O 3 coatings Loss measurements on SiO 2 /Ta 2 O 5 at low T Loss measurements on SiO 2 /Al 2 O 3 at low T Design and construction of the connection element between the fibres and the test mass Production of Si, CaF2, Mo and Ru fibres Modification of the cryogenic facility in Frascati Modification of existing cryogenic facility in order to prepare the mirror cooling and reduce the mechanical noise Development of low temperature accelerometer for vibration noise measurements Loss factor measurements between 4K and 300K Design and implementation of the electromechanical transducer for the detection of the acoustic emission Noise vibration measurements at low temperature to qualify the refrigeration system Computer simulation study based on finite element software concerning transmission of refrigeration power, thermal gradient distribution and vibration transmission for the last stage suspension Cryogenic Suspension for Resonant Detectors The MiniGrail spherical detector is cooled down to temperatures around mk Measure the thermal path conductance from the mixing chamber of the dilution refrigerator to the sphere Measure the heat-treated copper links and silver links Measure the transfer function of the attenuation masses with the new spring supports Measure the Brownian noise of the antenna Updated : 15 Apr. 04 Part B: 15 / 32 Pages /

16 Table 5 - Temporal development of the project tasks over the first eighteen months (Continued) TASK 6 Months 12 Months 18 Months Cryogenic Suspension for Interfero meters 10 Facility for Thermo- Elastic noise 11 Facility for Photo-Elastic noise 12 Selective Read-out schemes Test Quantum Design SQUIDs similar to those that the Legnaro group is using, on a capacitive three-mode transducer Test the DC-SQUID coupled to a relaxation-oscillation SQUID made in Twente. Mount it on a capacitive double-mass transducer developed with the Roma group Develop the 3-mode magnetically coupled transducer Design and test several high-compliance very high thermal conductivity suspensions for the interferometer mirrors Design a cryogenic facility for testing a full-size model of a super-attenuator with a suspended mass to be cooled to ~5K Modification of a small cryogenic facility First tests of the high-compliance very high thermal conductivity elements for metal, glass and sapphire masses Evaluation of the noise sources related to the cryogenic operations: liquid Helium and nitrogen boiloff. Study the possibility of using pulsed-tube refrigeration instead of liquid helium Optimization of the frequency stabilization of the master and slave lasers in the IGR interferometer Installation of the reaction pendulums for the control of the measuring cavity in the IGR interferometer Sensitivity upgrading of the interferometric system in Perugia Test and set-up of high finesse cavities at low temperatures Realigning the interferometer after the optics have been tested and suspended again Measurements of photo-thermal effects in fused silica substrates at low temperatures. Investigation of the effect of the laser spot size and of the coatings at room temperature Evaluation of the expected noise for "dual" resonant detectors at the SQL when a selective and wide area detection strategy is applied Development of a Folded Fabry-Perot cavity at room temperature Development of concave-convex cavity at room temperature Implementation of a selective read-out scheme to the capacitive transducer Study of wide area read-out using r.f. superconducting cavities Updated : 15 Apr. 04 Part B: 16 / 32 Pages /

17 WORK GROUP (1) Advanced materials for mirrors substrates (2) Advanced materials and techniques for resonant detectors (3) Investigation on superconductin g materials (4) Development of low loss dielectric coatings for advanced detectors (5) Innovative materials for advanced detectors suspension Table 6 - Summary 5 year execution plan Updated : 15 Apr. 04 Part B: 17 / 32 Pages / Joint Research Activities JRA3 STREGA PARTICIPANTS 5 YEAR EXECUTION PLAN (task deliverables and milestones) (Europe only) YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5 CNRS (lead), IGR, INFN (co-lead) INFN (lead), IGR, LEIDEN (co-lead) INFN CNRS, IGR (lead), INFN (co-lead) IGR (co-lead), INFN (lead) Milestones Deliverables Milestones Deliverables Milestones Deliverables Milestones Deliverables Milestones (a) Measurement facilities fully operational (b) mechanical and optical parameters (a) Room temperature meas. (optical and mechanical) on Si and CaF2 (b) Firsts devices for low temperature operations (a) Completion of cryogenic test facility (b) Test of elastic coupling of dissimilar materials (c) Capacitive transducer read by double SQUID amplifier (a) Resonator prototypes (b) Increasing to 50 MVm the electric field in capacitive transducer (a) Test Set-up for RF cavity measurement Ready (b) Trial Cavity Mock-up built (a) First Tests on The mock Up Cavity (a) first production of samples SiO2/Ta2O5 and SiO2/Al2O3 (a) Room temperature firsts measurements (b) Calibration of the experimental set-ups (a) Facilities for the measurement of mechanical properties fully operational (b) Loss angle measurement facilities fully operational (c) Mono-crystalline fibres production facility operational (a) Low temperature facilities fully operational (b) Silicate bonding samples preparation (a) Low temperature meas. (optical and mechanical) on Si and CaF2 (b) Si doping design (a) First cryogenic Q measurements (b) Test of a transducer on a sphere (c) Optical transducer at cryogenic temperatures (a) Cryogenic Q values for Mo, SiC and Be (b) Measurement of coating Q effect in optical transducer (a) Cryogenic Set Up, For Superconducting materials, Installed (b) Complete design Of a Prototype cavity. (a) First tests on a Superconducting prototype (b) Construction Drawings for a Prototype cavity ready. (a) first production of samples SiO2/high n (a) Coating losses measurements at room temp. for SiO2 substrates (b) Identification of diffraction coating production processes (a) Completion of the facility(ies) for loss angle measurement at low temperature (b) Local cooling (anti-stokes fluorescence) facility(ies) implementation (a) Optimal doping parameters (b) Silicate bonding optimal solution (a) Study of doping completed (b) Study of silicate bonding completed (a) Investigation of mechanical losses vs. heat treatment (b) Investigation of limiting E field in electrostatic transducers (c) More sensitive capacitive transducer read by double SQUID amplifier (a) Protocol for resonator fabrication. (b) Increasing Q factor and bias electric field by chemical, heat and coating treatments (a) First Niobium on Copper cavity Fully Characterized (b) Niobium Sputterd High Mechanical Q materials Produced. (a) Niobium On copper cavity built. (b) DC Characterization of Superconducting Sputtered samples (a) Definition of fabrication process for SiO2/Ta2O5 and SiO2/Al2O3 (a) Improvement of the coating performances at low temperature (b) Optimisation of the diffraction coating fabrication (a) Definition of geometrical and chemical properties of suspension fibres (b) Definition of the production procedures for suspension fibres (a) Prototypes of mirrors substrates (a) Prototypes designing (b) Identification and commissioning of a company (a) Study of effects of dielectric coating on resonators. (b) Construction of optical and superconducting transducers (c) Optical transducer at ultracryogenic temperatures (a) New high performance devices completed (b) Alignment and power control of the optical component in ultracryogenic environments CryogenicvTests and Full Characterization (mechanical and electrical) of a RF Superconducting Detector-Transducer (a) Technology Transfer To a company For The prototype construction (b) First Results On The final Cavity Prototype. (a) Production of transmissive optics prototypes (b) Production of reflective optics prototypes (a) Definition of optimal process for SiO2/Ta2O5 and SiO2/Al2O3 (b) Definition of optimal process for SiO2/high n (c) Definition of optimal process for diffraction coatings Prototype of an advanced suspension for GW detectors Final report Final report Final report Final report

18 WORK GROUP (6) Study of thermoelastic effects caused by absorption of cosmic rays (7) Cryogenic Last Stage Suspension (8) Cryogenic suspension system for advanced resonant detectors (9) Cryogenic suspension system for interferometers (10) Set-up of a facility for the measurement of thermoelastic noise Joint Research Activities JRA3 STREGA PARTICIPANTS 5 YEAR EXECUTION PLAN (task deliverables and milestones) (Europe only) YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5 (a) Measurement at room (a) Measurement of mechanical (a) Room temperature temperature of thermal and and thermal properties of measurement of loss angle and mechanical properties of autoproduced fibres temperature suspension fibres at low Deliverables Mechanical properties of Prototype design Final report commercial fibres and samples (Si, (b) Identification of optimal (b) Local cooled fibres thermal noise YAG ) dopants for crystalline fibres measurement INFN (lead) LEIDEN (co-lead), INFN (lead) LEIDEN (lead), INFN (co-lead), INFN INFN (co-lead), IGR (lead), CNRS, LEIDEN Milestones Deliverables Milestones Deliverables Milestones Deliverables Milestones Deliverables Milestones Deliverables a) Linac electron beam with bunches of > 10 4 electrons b) Experimental set-up for room temperature measurements Room temperature measurements on Al using an electron particle beam (a) Modification of existing cryogenic facility (b) PT refrigerator Software Simulation of the heat transmission trough payload (a) Cool down of Minigrail to 50 mk (b) Investigation of heat transfer from MC to sphere Transfer function measurements of cryogenic suspension Prototype of an anti-seismic mechanical filter equipped with items for heat removal Preliminary design of an antiseismic suspension with items for heat removal and concerning cryostat (a) Continuous locking of the laser to the 10m cavity (b) Design of the short measuring cavity (a) New frequency stabilization system for the IGR interferometer Experimental set-up for low temperature measurements on Al Low temperature measurements on Al using an electron particle beam (a) PT refrigerator integrated in the cryogenic facility (b) Accelerometer at low temperature (a) Design of the first payload prototype completed (b) Measurements of heat and vibration transmission (a) Test of double stage dc SQUIDs at T <0.1 K (b) Noise tests with a capacitive transducer (a) Choice of most suitable superconductive amplifier for Minigrail readout (b) Measurement of thermal noise at T<0.1 K Chain of mechanical filters with items for heat removal Measurement of mechanical attenuation and heat transfer performance of a chain of filters (at room temperature) (a) First locking of the measuring cavity to the laser (b) Measurements at the resonance on Si membranes (a) Perugia facility in continuous operation (b) New seismic noise isolation in the IGR facility Experimental set-up for low temperature measurements on Cu Low temperature measurement on CuAl data analysis and theoretical interpretation Payload prototype integrated in the cryogenic facility (a) Therm. Gradient measurements (b) Noise measurement on the cryogenic mirror Development of 3 mode readout system for Minigrail Optimisation of transducer system for a spherical antenna Suspension prototype for cryogenic environment assembled at room temper. Room temperature characterization and control tests of the Suspension (without payload) (a) First measurements on crystals with the IGR facility (b) Broadening of the detection band in the Perugia facility (a) Design of the cryogenic upgrade of the IGR facility Experimental set-up for low temperature measurements on Si (a) Low temperature measurement on Si (b) Overall data analysis and theoretical interpretation (a) Second prototype of payload integrated with the suspension system (a) Design and construct. of the second prototype (b) Full characterization of the first payload prototype Minigrail Operational with 6 complete transducers Minigrail in data taking with good g.w. sensitivity Full suspension in cryogenic environment, integrated with payload (see point 7) Characterization of the full suspension in cryogenic environment (a) Noise performance measurement of cryogenic cavities (a) Installation of the cryostat around the measuring cavity in the IGR facility Final report Final report Final report Final report Final report Updated : 15 Apr. 04 Part B: 18 / 32 Pages /

19 WORK GROUP (11) Direct measurement of the photoelastic noise (12) Development of selective read-out schemes Joint Research Activities JRA3 STREGA PARTICIPANTS 5 YEAR EXECUTION PLAN (task deliverables and milestones) (Europe only) YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5 INFN (co-lead), CNRS (lead), IGR IFN (lead), INFN, CNRS (co-lead) Milestones Deliverables Milestones Deliverables Experimental test of photo thermal effect at room temperature Higher frequency stabilization of reference cavities Estimation of noise reduction of Folded Fabry Perot cavity and concave-convex cavity with respect to conventional cavities Noise estimation of the Dual detector with capacitive and/or optical read-out Experimental test of photo thermal effect at room temperature on different substrates and spot size Design of a wide area and selective read-out either capacitive and optical Conceptual design of dual detector Measurements at low temperatures of dynamic photo thermal. noise Cryogenic reference cavities with high frequency stabilization Optimisation of wide area read-out to dual detector either capacitive and optical Construction of room temperature prototypes Measurements at low temperatures of mirror induced thermal noise Mechanical transfer function at low temperatures of the prototype Final design of dual detector Final report Final report Updated : 15 Apr. 04 Part B: 19 / 32 Pages /

20 2. QUALITY OF THE MANAGEMENT 2.1 Management and Competence of the Participants INFN. The Istituto Nazionale di Fisica Nucleare has funded research on gravitational wave detection since the seventies when Edoardo Amaldi started his pioneering work in this field. As a result of its increasing interest, the INFN has funded the construction of three resonant detectors (AURIGA, EXPLORER, NAUTILUS), one 3 km arm length interferometer (VIRGO, in collaboration with CNRS) and the development of the new superconducting RF cavities (PACO). The laboratories listed in Table 1 have acquired a level of knowledge and experience in the GW detection field recognized all over the world. IFN. The Istituto di Fotonica e Nanotecnologie of the CNR and ITC has contributed with its researchers to the construction and commissioning of the detector AURIGA particularly as regards the SQUID amplifier and its noise matching with the capacitive transducer. Recently its contribution has extended to the study of new transduction-amplification systems based on a nonresonant selective read out. CNRS. The Centre National de la Recherche Scientifique enters as a participant in this JRA through the four groups listed in Table 1, which have produced a very relevant and, sometimes, unique contribution to advances in the field of GW detection and to the construction of the interferometer VIRGO. LEIDEN. The Physics Department of University of Leiden is a world centre for the most advanced cryogenic technology. The group MiniGRAIL is responsible for the construction of one of the two spherical resonant detectors in the world, the second being under construction in Brazil. Its expertise is fundamental to the development of cryogenic suspensions for future detectors. IGR. The recently founded Institute of Gravitational Research is the new administrative organization of the historical group of the University of Glasgow that has contributed continuously over the last 30 years to the major developments in the field of GW detection. To date it built and operates the 600m arm length interferometer GEO600 that uses innovative technologies in optics configuration and in mechanical suspensions Management Structure Table 7 shows the several working groups that will effectively carry out the scientific activities foreseen in the different tasks of the project. The same table gives some details on the expertise and the facilities that each working group is prepared to share with the others. At the first level, the managing of the JRA STREGA is done by the working group co-ordinators listed in Table 7. Their task is to keep the work of their group in line with the time table fixed by the upper level of management. The second level of management is provided by the Task Supervisors (TSs) listed in Table 8. They will organize regular meetings with the group co-ordinators in order to assess the state of the activities with respect to the main working plan (Table 4) and revise the short term one (Table 5) every six months. Each TS with the relevant Group Co-ordinators form the Executive Board. Updated : 15 Apr. 04 Part B: 20 / 32 Pages /