1. Tandem Fabry-Perot Spectrometer SQUEAN: S pectrometer for QU asar in EA rly u N iverse Presented at The 2 nd Survey Science Group Workshop, High1 Resort on 2012 Feb 14 by Soojong Pak (Kyung Hee University)

2. Classification of Spectrometers

3. Types of Dispersing Elements MechanismTypeImage refractionPrism Spec. Slit (1D) diffraction, interference Grating Spec. reflection, interference Fourier Transform Spec. Imaging (2D) Fabry-Perot Spec.

4. Slit Sp. vs. Imaging Sp. Imaging Spectrometer Slit Spectrometer

5. DATA Format Spatial Direction Imaging Spectrometer Slit Spectrometer

6. Other Kinds of Imaging Spectrometer: Integral Field Unit

7. Other Kinds of Imaging Spectrometer: Multi-Object Spectrometer

8. What is Fabry-Perot Spectrometer?

9. Finesse Fabry-Perot Parameters Path Difference m = 1 2 3 ….

10. Basic Etalon Equations

11. Simulated Spectra 10 um5 um m=10m=9m=8m=11m=12m=13m=7 FSR

12. Simulated Spectra 10 um5 um Order Sorting Filter

13. Simulated Spectra 10 um5 um

14. Order Sorting Method of Tandem Fabry-Perot Telescope Collimator Camera Lens Detector FP-A (m=20) FP-B (m=250)

15. Disadvantage of FP Spatial Direction  Takes Long Time for Wide Spectral Band

16. Advantage of FP Spatial Direction  Takes Many Targets for Short Spectral Band

17. Suggested Fabry-Perot Spectrometer

18. Specifications Target Emission Lines at Optical Bands –[OII] 372.7nm –H  486.1nm –[O III] 495.9 500.7nm –H  656.2 nm –[SII] 671.6 673.1 nm Spectral Resolutions –The spectral resolution R = Finesse X m, where Finesses comes from the FP mirrors reflectivity and the order of interference, m, from the mirrors distance. –If Finesse=40 and m=50-250, we can expect that R = 2000 – 10000 FOV (in case we use CQUEAN CCD) –13 um 1024 X 1024 –Total FOV 5 X 5 arcmin with 0.27 arcsec/pixel

19. Sciences (1/2) Emission Lines of Star Forming Regions in the Galaxy (Soojong Pak) Emission Lines of Star Forming Regions in the nearby galaxies (Luis Ho suggested) Emission Lines of Merging AGNs (Julia Comerford suggested) –Ref. Comerford et al. 2012, ApJ, 753, 42, Kpc-Scale Spatial Offsets in Double- Peaked Narrow-Line AGN. I –Ref. Liu et al. 2011, ApJ, 737, 101, AGN Pairs from the SDSS. I. Narrow Emission Line Survey of Galaxies at z=1. –H_beta 486nm, [OII] 372.7nm –Ref. Glazebrook et al. 2004, AJ, 128, 2652, Cosmic Star Formation History to z=1 from Narrow Emission Line Selected Tunable Filter Survey

20. Sciences (2/2) Dark Matter in Globular Clusters (Karl Gebhardt) –1000 Stellar velocities at the edges of the visible clusters in order to constrain the dark matter distributions. –R=10000 for velocity accuracy of 1 km/s –m_R = 20 – 21 mag Chemical Composition Studies in Globular Cluster (Chris Sneden) – a search for (the rare) Li-rich giant stars. The Li I resonance line is at 6708A – characterizing Na variations in clusters. One could choose Na D lines, but probably I would be happier with one of the 5680A doublet lines. – searching for Ba abundance variations. Probably the 6496A or 6141A lines are best. – finding out the level of metallicity variations as a function of evolutionary state. One could use one of the Ca IR triplet lines, for example.

21. 2011-02-082011 IR Workshop McDonald Observatory Otto Struve 2.1m telescope

22. CQUEAN at 2.1m telescope 2011-02-082011 IR Workshop Control PC Guide CCD field rotator Guide CCD Science CCD Motor for guide CCD field rotator Filter Wheel

23. Science CCD Camera (Andor iKon-M 934 BR-DD) 2011-02-082011 IR Workshop CCD E2V Deep Depletion Chip Pixels1024 x 1024, 13μm Readout Speed 2.5 MHz (0.4 sec) 1 MHz (1 sec) 50 kHz (20 sec) QEBetter than 25% at 1 μm FringeNone RD Noise (Measured) 8.1 electrons/pixel

24. Possible Designs of Tandem Fabry-Perot FP-A (m=20) FP-B (m=250) Serial Configuration of 2 etalons Integrated Configuration of 3 mirrors

25. Etalon Specifications for Tandem Fabry-Perot Basic Specifications – We use two etalons for high spectral resolution (ET-H) and low spectral resolution (ET-L). – The ET-L will sort the overlapped orders of ET-H. – We also need broad band filters for the overlapped orders of ET-L. – The mirror sets and housing of ET-H and ET-L are identical. The only difference is the mirror distances. Etalon Specs EtalonFinessemRd [nm] ET-H15650250375081,2502.603250.1721.7 ET-L15650203006,50032.53252.1721.7 ET-H406502501000081,2502.603250.0658.1 ET-L40650208006,50032.53250.8138.1

26. Fore-Optics Design We need collimator units and camera units before and after the Fabry-Perot. Telescope Collimator Camera Lens Detector FP-A (m=150) FP-B (m=10)

27. Fore-Optics Design with Traditional Lens System Example from CQUEAN Focal Reducer

28. Fore-Optics Design with Off-Axis Mirrors We can apply the off-axis mirror design of Dr. Seunghyuk Chang. The mirrors of a confocal system do not need to have a common axis for a perfect image at the system focus Eccentric section of an on-axis parent system

29. Re-imaging Optics for KASINICS (cf. Offner System)

30. Schwartzschild-Chang Type Telescope - from "Inverse Cassegrain" - on-axis (Schwartzschild Type) off-axis (Schwartzschild-Chang Type) D=50mm, F/D=2 et al. 2011 (Kim, Pak, Chang et al. 2010) paraboloid ellipsoid

31. Off-Axis Design for SQUEAN (by Chang)

33. Spot Diagrams 13um ( x,y )

34. Project Roadmap and Required Resources Work Definition GS Labor [year] Cost [M KRW] Comments Etalon Development360 Fore-Optics (Off-Axis Mirrors or Lens) 230 Telescope Interface and Structure0.510 Instrument Operation Software0.5 Data Reduction Software1Karl Gebhardt Telescope Installation and Commissioning 0.530 TOTAL7.5130 Cost includes HW and Travel.

35. Appendix

36. Fabry-Perot Etalon Vendors Bristol Instruments –They make the replacement FP mirrors for OLD Burleigh RC series. –The basic price for one set of mirrors starts from $8,000. –The man in the company recommends www.lightmachinery.com for custom- made etalons.www.lightmachinery.com LightMachinery.com

37. Etalon LightMachinery.com –They make customized Etalon mirrors. –Piezo Tunable Etalons with clear aperture of 4 mm. –Ian Miller, Director of R&D, gives very kind detailed technical supports.

38. PZT Tunable Etalon Housing ThorLabs.com –Scanning Fabry-Perot Interferometer: SA210-5B 535-820 nm, 10 GHz FSR $2,533 This is for laser, but we can use this for scanning test. –PZT Drives & Actuator: PE4 Micrometer Travel Range = 4mm with 1 um resolution PZT Travel Range = 15 um with 10 nm resolution 3 X $479.60 / unit –Open-Loop PZT Controllers: MDT693A 3 Channel $1,580 –Piezoelectric Actuators Open Loop Piezo Actuator, 17um/150V: AE0505D16F, $153 Full Bridge Strain Gauge Piezo Actuators, AE0505D16F: PZS001, $175 Strain Gauge Amplification Circuit, AMP002, $161 www.PhysikInstrumente.com

39. Coefficient of Thermal Expansion Fused Silica –CTE = 0.55 ppm/K Invar –CTE = 0-2 ppm/K Piezo Material –CTE = 6E-3/K http://www.piceramic.com/datasheet/Piezo_Material_Datasheet_Cofefficients_Te mperature_Measurements.pdf