Post on 28-Dec-2015
1 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Alignment: Virgo+ changesAlignment: Virgo+ changes
2 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
• Fast quadrant centering systemFast quadrant centering system
• New Alignment electronicsNew Alignment electronics
• Anderson technique?Anderson technique?
TopicsTopics
3 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Fast Quadrant Centering SystemFast Quadrant Centering System
4 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Present centering systemPresent centering system
Translation stage centering < 0.3 Hz
Q1p
Q51 Q22
Q21
Q72
Q71 Q81
WSR10
5 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Requirements for centeringRequirements for centering
With the present centering configuration (activates every few minutes)
RMS change of a factor of 4
Extrapolating from these measurements…
Taking a reasonable range around the “minimum”, the maximum DC asymmetry must be less than 0.1
Even with the best centering rate now possible (every 4-5 seconds) we can’t reach this precision.
G. Vajente
6 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Test of GEO system on NE benchTest of GEO system on NE bench
QD
B7_q2
7 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Galvo feedback on NE bench (07/2006)Galvo feedback on NE bench (07/2006)
Quadrant Electronics
ADC
DC Signals
Asymmetry computing
DAC
Galvo Driver
Filter
Qr Server
Tilting Mirrors
DOL (DAQ)
• Digital feedback• Used existing Qr server (slightly modified)
• 30 Hz bandwidth
• Commercial galvo driver tested at EGO: OK
8 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Galvo system performance IGalvo system performance I
Centering is given in normalized asymmetry
T-stage centering
Galvo centering
9 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Galvo system performance IIGalvo system performance II
Error signals
Correction signals
Galvo on
Beam position fluctuations become visible in the correction signal
Galvo offGalvo on
10 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Fast galvo centering: costFast galvo centering: cost
QD's to be equipped 10
pcs spares price totalGalvo G102 20 4 415 9960Driver A 102 20 4 227 5448Mechanics 10 2 50Mirror substrate 20 4 24 576Coating 1 0 1000 1000Mirror mount 10 2 200 2400
Total 19434
Estimate; to be updated with recent information
11 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Possible work planPossible work plan
Suggestion: we should start preparing the system nowLast tests finished successfully (galvo drivers)
Procurement of material (2 months)Delivery time of galvos, drivers, mirrors, mirror holdersRealization of mechanics
Check space constraints on benchesMake new optics layout
Prepare new version of GcReading galvo voltages instead of QD DC signals
Implementation (2 shifts per bench)Rearrangement of mirrorsCablingReconfiguration of Qr server, connection to GcAdaptations in Alp
=> Could be implemented after science run, or for Virgo+
12 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Possible planninngPossible planninng
Implementation Plan
M1 M2 M3
Tasks and Deliverables W1 W2 W3 W4 W1 W2 W3 W4 W1 W2 W3 W4
Tasks
1: Order galvos, …
2: New bench designs
3: Modify mechanical drawings
4: Production of mechanics
5: Adapt global control
6: Install new centering system
Deliverables
1: Mechanics
2: Galvo assemblies
3: New centering system
From change request draft; to be confirmed
13 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
New Alignment ElectronicsNew Alignment Electronics
14 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
New alignment electronicsNew alignment electronics
Demodulation boardSpares with slight improvements – Higher LF cut-off– 4 gain settings (instead of 2)– …
QD front-endsImproved version, but fully compatible (mechanical, connectors,…)– Higher light power– Lower electronics noise– Lower offsets– Better geometrical configuration– Changeable gain– …See Virgo CHRQ 008/2006
15 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
LA electronics statusLA electronics status
Demodulator2 prototype boards received and tested - OKOne of these boards is now used for Q22 (8 MHz)3 more (final) boards under production as spares
Front-end electronicsLarge delay due to manpower problems
Tentative planning (CHRQ) was: delivery ~ Feb. 2007
Present plans: 1. Produce some spares (for run?)2. Produce enhanced version
Design review needed before production of final FE’sCHRQ contains some big changes
Planning/status: See talk by Jo
=> Wait for discussions with Nikhef before making planningBut possible scenario:– Spares for science run– Enhanced version for IInd commissioning period or Virgo+
17 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Anderson: Anderson: fundamental mode fundamental mode resonanceresonance
Carrier
Upper Sideband
Lower Sideband
TEM00
18 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
TEM01
Anderson: Anderson: 11stst order order resonanceresonance
Carrier
Upper Sideband
Lower Sideband
LMC = 143.5722 mfmod = 6264287 Hz
19 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Anderson: optical schemeAnderson: optical scheme
Get two more outputGet two more outputports for alignment ports for alignment (4 quadrant diodes)(4 quadrant diodes)
20 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
What we should think aboutWhat we should think about
Necessity of end quadrants not clearPresent Virgo might function without themVirgo+ ?
Effects of Anderson frequencyAnderson offset (during CITF): made locking more difficult
Still an issue?
Stronger mixing of alignment error signalsWithout Anderson frequency, maybe no need of 2nd modulation
Simulations to be done
Effort needed for abandoning Anderson frequencyShift MC length (5 cm for 2 kHz freq. shift)Other?
No investigations started yetIf you have an opinion, please give your arguments
22 Ist Virgo+ review Cascina 03.04.2007H. Heit mann
Fast galvo centering: costFast galvo centering: cost
QD's to be equipped 12
pcs spares price totalGalvo G102 24 4 415 11620Driver A 102 24 4 227 6356Mechanics 12 2 50Mirror substrate 24 4 24 672Coating 1 0 1000 1000Mirror mount 12 2 200 2800
Total 22498
ITF quadrant diodes + MC quadrant diodes(caution: IMC QD’s have integrated demodulator!)