Precise wavelength reference for Spirou F. Pepe, F. Wildi, B. Chazelas, C. Lovis, S. Udry.
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Transcript of Precise wavelength reference for Spirou F. Pepe, F. Wildi, B. Chazelas, C. Lovis, S. Udry.
Precise wavelengthreference for Spirou
F. Pepe, F. Wildi, B. Chazelas, C. Lovis, S. Udry
The wavelength calibration
px
λi ref
xi
λx
Thorium lines
Achieved Δλλ: (Absolute) accuracy: 5 x 10-8
Scale factor: 3 x 10-8 Repeatability: 6 x 10-10 (= 20 cms-1)
The perfect calibrator
Cover full spectral range
Constant line spacing
Lines width < spectrograph resolution
High density of lines, up to one per ~2-3 SE
All wavelengths precisely known and stable
Homogeneous line intensities, high ‘brightness’
Fabry-Pérot or Laser frequency comb
The perfect calibrator
HARPS FPCS System
Vacuum control
Temperature control
Light source
HARPS Fabry-Pérot Assembly
Fabry-Pérot at La Silla
Calibration Unit
FPCS Spectrum with HARPS
FPCS Specifications
FPCS short-term RV-stability
Time series of 7 hours
FPCS long-term RV-stability
Nightly calibration over 80 nights
New-generation FPCS
Mechanics instead of glass work (maintenance)
New white light source (reliability and costs)
Mirrors instead of lenses (wide range, IR) for collimator and camera
Optimize etalon for stability and throughput over the specified spectral range
Etc.
Spirou FPCS configurationSupercontinuum laser or LDLS (laser-driven Xe)
Fiber-link from source to vacuum vessel
Vacuum vessel (fiber in- and output)
Thermal control
FPCS opto-mechanics (support and mirrors)
FP etalon
Fiber from vacuum vessel to calibration unit
Interface: Standard FC or SMA fiber connector (Etendue TBD)
LDLS light source
Up to 2400 nm !(like 10’000 K BB)
New opto-mechanics design (in progress)
Spirou FPCS capital cost
Light source: 25’000 EUR
FP etalon: 20’000 EUR
Vacuum vessel: 10’000 EUR
Vacuum gauges and control: 15’000 EUR (TBC)
FPCS opto-mechanics: 25’000 EUR
Thermal control: 5’000 EUR
Fibers: 2’000 EUR
Total: 102’000 EUR (TBC)
Spirou FPCS manpower costs
Requirements definition: 0.1 FTE
Design optimization: 0.3 FTE
Procurement of components: 0.2 FTE
Opto-mechanics manufacturing: 0.5 FTE
Assembling and adjusting: 0.2 FTE
Testing and tuning: 0.2 FTE
Total: 1.5 FTE (TBC)
Spirou FPCS travel costs
Roughly 10’000 EUR per phase (depends strongly on number of meetings and reviews)
Total: 40’000 EUR (TBC)
Does not include participation to (other) workgroups