R&D activities in Florence

Geppo CagnoliINFN and U. of Glasgow

WG2 & WG3 Meeting – 27th Apr. 2006 - Firenze

27th April 2006 WG2/3 Meeting - GWA - Firenze 2 of 19

Firenze/Urbino group• 6 Staff members working on STREGA:

• Flavio Vetrano Francesco Marin• Filippo Martelli• Giovanni Losurdo• Francesco Piergiovanni• Geppo Cagnoli

• Supporting staff members:– Andrea Vicere’– Gianluca Guidi

• 2 Post docs: Enrico Campagna Francesco Marino

• 2 PhD Students:Matteo LorenziniElisabetta Cesarini

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Firenze and Urbino

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Activities on thermal noiseActivities on thermal noise• Modelling of thermal noise for Virgo optics and suspensions

(funded by EGO)• Measurements on crystalline silicon fibres (CRYSTAL

collaboration, funded by INFN )• Study of new materials for 3rd generation interferometric

GW detectors (JRA3-STREGA collaboration)

27th April 2006 WG2/3 Meeting - GWA - Firenze 5 of 19

Silicon fibres measurements setup

Vacuum chamberP = 10-5/10-6 mbar

Fibre is clampedwith 2 Al blocks

Fibre profile measurements setup Finite element analysis

X-Y shadow sensor

exciterphotodiodes

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Achievements• Profiling and modelling

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Achievements cont.• Measurements

L=111.5 mm average diameter 242 m

L [mm] Y [GPa] [1/K] [W/(mK)] c111.5±0.5 150±11 (2.54±0.13) 146±13 0.018±0.002308.0±0.5 174±12 (2.56±0.11) 138±11 -

L=308 mm average diameter 574 m

2

)1(16.21dccf

Vpp

27th April 2006 WG2/3 Meeting - GWA - Firenze 8 of 19

Open points• Excess losses with 1.5mm diameter fibre

0.0E+00

2.0E-05

4.0E-05

6.0E-05

8.0E-05

1.0E-04

1.2E-04

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000Frequency [Hz]

loss

ang

le

48kg round

55kg flat

New clamp handtightenedSlotted clamp 100 kg

Slotted clamp - brokenfibreShort head - handtightened

9.19e-4

thermoelastic

27th April 2006 WG2/3 Meeting - GWA - Firenze 9 of 19

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

0 500 1000 1500 2000 2500 3000Frequency [Hz]

Am

plitu

de

[V]

Without massWith 600 g mass

Open points cont.• Like in Glasgow we used a piezo for sensing

and for exciting the structure

Fibre

Structure

27th April 2006 WG2/3 Meeting - GWA - Firenze 10 of 19

Open points cont.• Excess losses are higher for the “orthogonal”

than for “parallel” modes (!!)

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

10 100 1000 10000

Frequency [Hz]

Am

plitu

de

[V]

12

34 5

6 7

orthogonal

parallel

2 23

11 63.2 10 N1 mm 20 cm 1.7 10 Pa 10 J 11

id L E TF

1224

11 65.8 10 N m1 mm 20 cm 1.7 10 Pa 10 J

d L E TM

Force and torque on the clamp(G.Cagnoli, F. Martelli, F. Piergiovanni)

27th April 2006 WG2/3 Meeting - GWA - Firenze 11 of 19

Cryogenic facilityStudy of the properties of materials suitable for 3rd generation

interferometric GW detectors

Crystalline Silicon Samples

To be performed inside the JRA3-STREGA collaboration

Measurements concern

Q measurements (possible, but our set up is not

optimized for this)

Thermal conductivity

Thermal expansioncoefficient

27th April 2006 WG2/3 Meeting - GWA - Firenze 12 of 19

The cryostat

30 cm

A.S. Scientific cryostatExperimental volume: about 14 dm3

Inner cold shield

Outer cold shield

Optical windows

Optical windows

Inner tank Liquid He

Outer tank Liquid N2

Vacuum chamber

Experimental chamber

27th April 2006 WG2/3 Meeting - GWA - Firenze 13 of 19

Thermal conductivity measurement

INSULATORBOX

HEATER

COPPERBOX

CLAMP

SAMPLE

THERMOMETERS

SAMPLEHEATER

t

ΔTP = R

ΔT = 1 K

t t

L = R S

27th April 2006 WG2/3 Meeting - GWA - Firenze 14 of 19

Measurement of the power loss• We are measuring the heat lost by wire conduction and radiation

INSULATORBOX

HEATER

COPPERBOX

CLAMP

SAMPLE

THERMOMETERS

SAMPLEHEATER

1mW of heating power

At room temperature we have measured:

Heat Capacity of the sample 4.2 J/KHeat Conductivity 3.7 mW/K

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Thermal expansion measurement facility

27th April 2006 WG2/3 Meeting - GWA - Firenze 16 of 19

Measuring cavity

Sample

Mirrors Fixed clampMobile clamp

Laser

Very soft elastic blades

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The reference cavityVacuum chamber hosting reference cavity

Heating wires for RC temperature control

Mirror Reference material: zerodur

Piezo actuator

Elastic Cu/Be blades

1 h

1 KResult of the temperature stabilization

(Matteo Lorenzini)

27th April 2006 WG2/3 Meeting - GWA - Firenze 18 of 19

Frequencyservo loop

Laser EOM1O.I.BS

PD1 QW

PBS

13.3 MHz

PD2

QWPBS

PD4

Cavity servo loopAOM

EOM2

C1

C2

PD3

Oscilloscope+

PC

Photothermal effect facilitySmall spot size results

Low frequency:size effect

High frequency:coating effect

27th April 2006 WG2/3 Meeting - GWA - Firenze 19 of 19

Conclusion• First measurement of thermal

conductivity expected soon

• The reference cavity for thermal expansion measurements is being assembled

• Photothermal facility is working successfully

• We are looking forward to show you our labs tomorrow afternoon