The status report of the AURIGA detector

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The status report of the AURIGA detector
Luca Taffarello (INFN Sezione di Padova) on
behalf of AURIGA Collaboration
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Summary of the talk

• New detector set-up
• First Results, calibration and thermal behaviour
• Investigation of the un-modelled noise peaks
• Up-conversion of low frequency vibrations
• Solution of the problem
• New mechanical isolation at low frequency
• Result achieved very stable and gaussian
  behaviour
• Duty Cycle 98 (from 19th May 2005)

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Expected target AURIGA II run with 1999-2003
upgrades
new mechanical suspensions attenuation gt 360
dB at 1 kHz FEM modelled new capacitive
transducer two-modes (1 mechanical1
electrical) optimized mass new amplifier
double stage SQUID 200 h energy
resolution new data analysis C object
oriented code frame data format
More details Vinante talk Today afternoon
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Calibration The dissipations of the 3 sensitives
modes
Measurement of the real part of the impedence
seen by the SQUID

n865.68 Hz


QLV1.15 106
QHV1.15 106
n914.14 Hz
QLV5 106
QHV0.74 106
n955.63 Hz
QLV0.45 106
QHV0.75 106
HV ? E bias7.5 MV/m
Q in operation 400-1000 cold-damping
No evidence of discharge
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Calibration the mechanical transfer function of
the antenna

• A
• mechanical modes in the transducer charge line
• B
• Electromechanical modes
• C
• Mechanical modes of the charge plates

A
C
B
VERY IMPORTANT not evident excitation with
mechanical and-or electromagnetic actuators
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Noise hunting in cryogenic operation
Best initial result of II run

• Spurious peaks in the sensitive band
• High false alarm rate

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Raw Data
Non Stationary Performances
Sensitive frequency band
Time (5 hours)
It is possible to classify spurious peaks in
correlated Families (F1..F5..) in time families
appear and dissapear
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Low Frequency Motions are Up-Converted!
Accelerometer Inside vacuum chamber 8-22 Hz
894 Hz Spurious peak in the sensitive band
SQUID output 18-22 Hz
Seismometer 8-22 Hz
4 days friday-monday
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Strategy new mechanical isolation at low
frequency

• Step 1 Dissipation stacks
• material Polyurethane (Sylodamp by Angst
  Pfister),
• high dissipation Q2
• roll-off frequency 8-10 Hz
• Step 2 Active-air mounts (Vibraplane by Kinetic
  Systems)
• internal damping Q2
• lower natural frequencies 1-2 Hz,
• automatic leveling/height control
• Hardware up-grades integrated during cryogenic
  operations

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STEP 1 rubber stacks between floor and cryostat
supports
2 Dec. 2004
Position control feed-back lift used with the
liquid helium inside the dewars
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First breakthrough achieved design sensitivity
(Dec 2004)
(Note one-sided spectral sensitivity)
60 DUTY CYCLE !!! Go ahead !!
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Second Step seismic isolation up-gradeexternal
suspensions low frequency with vibrational damping
Air springs effective above 1-2 Hz
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Metal-arc welding on cryostat while keeping
liquid helium in
wings to support Auriga above the center of
mass of the cryostat
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Step 2 integration of low frequency suspensions
(May 19th)
Final configuration
Ferroconcrete Pillar
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Last breakthrough achieved 98 Duty Cycle (May
2005)
Before the up-grade
After the up-grade
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On line effect (May 19th)
Sensitive frequency band
suspension activation
1 hour
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Low frequency motion comparison
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Current AURIGA Burst Search

• Thermal at 4.5 K
• 13.6 days,
• Epoch vetoes not needed
• apart from cryogenic maintenance
• Duty time 98
• Very stationary
• Gaussian noise
• Outliers 9 events/day with SNR gt 6
• Event rate 3700 /day with SNR gt 4

Absolute amplitude 5.7 10-22 / Hz
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Evidence of the connection between the external
(seismic) activity and the spurious peaks
excitation in the sensitive band
sensitive bandwidth
OUTPUT of SEISMOMETER on top of the cryostat 0-22
Hz
1 DAY
to determine a correlation between the external
disturbances and the response in the sensitive
bandwidth
Evidence for nolinear behaviour