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New materials for DUAL: the LNL activity. Dual detector : Best material parameters. Two different materials ‘A’ and ‘B’ with two different Young modulus Y and density r Sensitivity curve optimized in the same frequency window QL readout Toroidal shape No thermal noise. - PowerPoint PPT Presentation
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New materials for DUAL:
the LNL activity
A
B
B
Α
B
Α
2
Y
Y
S
S
hh
hh
Dual detector : Best material parameters
• Two different materials ‘A’ and ‘B’ with two different Young modulus Y and density
•Sensitivity curve optimized in the same frequency window
• QL readout
•Toroidal shape
•No thermal noise
BΑ,hhS
BΑ,
BΑ,YStrain PSD of material A,B Young modulus of mat. A,B
Density of material A,B
/2Y
Dual detector : Candidate Materials
810/ TQ
-Diamond 163 ? expensive
-Silicon carbide 27 Not well known available in large size
-Berillium 24 <106 expensive
-Sapphire 13 108 expensive+need bonding
-Molibdenum 6.8 107 available in large size
-Silicon 4.4 >108 need bonding
-others ? (i.e. Alumina (17), MoCu (), CuBe)
5056/ Alhh
Mathh SS Q
1. Minimize sensitivity curve i.e. maximize
2. Minimize thermal noise
Red= Material under investigation
Sintered silicon carbide: results•Cantilevers of different thickness (0.3-0.5 mm) and lenght (5-10 cm)
•Both optical lever and capacitive readout
Similar results in E.K. Hu et al. Phys Lett. A 157, 209 (1991) -> Annealing should improve the Q
0 50 100 150 200 250 3004E-5
1E-4
8E-4
Loss
ang
le
Temperature [K]0 50 100 150 200 250 300
5E-5
1E-4
1E-3
Loss
Ang
le
Temperature [K]
Sintered silicon carbide: results
0 50 100 150 200 250 3005E-5
1E-4
1E-3
Loss
Ang
le
Temperature [K]
Sintered SiC Annealed 1900 C Annealed 1200 C
0 50 100 150 200 250 3004E-5
1E-4
8E-4
Loss
ang
le
Temperature [K]
Sintered SiC Annealed 1900 C Annealed 1200 C
•Cantilevers of different thickness (0.3-0.5 mm) and lenght (5-10 cm)
•Both optical lever and capacitive readout
Similar results in E.K. Hu et al. Phys Lett. A 157, 209 (1991) -> Annealing should improve the Q -->Seem not very much
Infiltrated silicon carbide C-SiC: results
•Best achieved loss angle 2x10-6
•Annealing did’nt improve the quality factor
•Measured samples: two cantilever of different thickness and lenght from Cesic (Germany)
•Different Carbon matrices
•Capacitive readout
Annealed
Not Annealed
0 50 100 150 200 250 3001E-6
1E-5
1E-4
1E-3
Loss
ang
le
Temperature [K]
I nfiltrated SiC thickness 5 mm 1030 Hz Infiltrated SiC thickness 3 mm 977 Hz
0 50 100 150 200 250 3001E-5
1E-4
1E-3
Loss
Ang
le
Temperature [K]
I nfiltrated SiC thickness 3mm Same annealed at 1900 C
Silicon samples: bonding research
•Ready made for many bond proccesses (Anodic bonding, Eutetic bonding,Adhesive bonding,Fusion bonding,Thermocompression bonding)
•Wafer diameter 100 mm
•Stack thickness 6 mm
Machine capabilities
A Silicon Wafer bonder is now availabe at the
Mt-Lab in Trento
Silicon samples: bonding loss angle
Bonding LayerSilicon wafer
Bonded silicon disk h=0.9 mm d=100 nm
)()( bondtot
bondbondednot E
E
Disk loss angle
Ansys Analysis
SS pistonSS spring
Sapphire balls 1mm
Si Disk
Not in scale cross section
Si disk suspension set-up
Al
Silicon <100>
<111> crystal plane side wall
TMAH
175 m deep pyramid hole, with square opening 500 m side
silicon bulk wet etchingSet up #1
SS springSS piston
Sapphire balls 1mm
Si Disk
Not in scale cross section
Si disk suspension set-up
Al
Hole about 300 m in diameter , Milled using dentist’s tools
Set up #2
Si disk displacement Readout
Laser
Quadrant photodiode
Achieved sensitivity
10-8 -10-9 m
Observed warm-up effects at low temperature !
Thus not ideal for ultracryogenic operations
Si disk displacement Readout
Rotate View
Capacitive readout
Vbias
Vout
Si disk: capacitive redout
Readout sensitivity
Achieved Sensitivity during run #1
(Vbias=60 Volt, gap= 0.1 mm)
][10][ 2 nmxVoltVout
High sensitivity require
00 /1 CC
x
dx
dC
C
VV
Par
biasout
Vbias
C(x)
•Small gap
•Low parasitic capacitance (Cpar)
•Low noise voltage preamplifiers (SQUID amplifer can improve sensitivity very much)
The comb capacitor capacitance value C(x) is a function of the distance (gap+x) between them and the opposite dielectric plate
Si disk: first cryogenic run set-up
• Si <100> oriented Boron doped
•Disk diameter 4 inch
•Thickness 0.5 mm
Misalignement problem
Adopted suspension (not optimized) set-up
Si disk
Sapphire balls
SS piston
2mm
Si disk: first cryogenic run results
0 50 100 150 200 250 3001E-7
1E-6
1E-5
1E-4
Mode freq 980 HzMode freq 997 Hz
Loss
Ang
le
Temperature [K]0 50 100 150 200 250 300
1E-7
1E-6
1E-5
1E-4
Mode freq 383 Hz
Loss
Ang
le
Temperature [K]0 50 100 150 200 250 300
1E-7
1E-6
1E-5
1E-4 Mode freq 484 Hz
Loss
Ang
le
Temperature [K]
First Si Disk cryogenic run: Quality factor limitations
• The contribution of thermoelastic damping and surface losses at 4.2 K should be less then 10-8
•We are presumably dominated by suspension losses and/or sample microfracture induced by manufacturing the central hole
•However for this specific run gas damping should play a relelvant role because we had a cold leak
mBarPmm
Kg/m4
Mode3
Si
1015.0H
Hz483ν2300ρ
P
1
M
RTνHρ
2Q
HeModeSi
3/2
Christian’s Model
8105.2Q
L
16
P
1
M
RTνHρ
2Q
HeModeSi
3/2Gap
mm
mm
35L
1.0Gap
7106.3Q Comb
Capacitor
Bao et al. Model (sqeezed film damping )
Even worse using true gas dynamic models and outgasing
Conclusions
•SiC is very interesting for its high sound velocity, but the sintered and the infiltrated silicon carbide, that can be fabricated in large size as required for the Dual detector, show at low temperature a quality factor that is at least 2 order of magnitude lower than the required value. The quality factor of monocristalline SiC should be better but in this case we have to develop low losses bonding procedures and take care of the cost.
•Monocristalline Silicon is also a candidate material but it is not available at the required size. We plan to measure the Si bond losses to evaluate if a big elastic body can be obtained bonding togheter smaller pieces without affecting the overall Q fator
•Molybdenum is the best candidate material for the Dual detector however we are considering other material considering other materials as MoCu, pure Alumina, CuAl