FMOS

FMOS

http://www.kusastro.kyoto-u.ac.jp/~iwamuro/FMOS/FMOS/

Iwamuro, F. (Kyoto Univ.)
Maihara, T. (Kyoto Univ.)
Akiyama, M. (Tohoku Univ.)
Kimura, M. (NAOJ)
Tamura, N. (NAOJ)
Takato, N. (NAOJ)
Tait, P. (NAOJ)
Ohta, K. (Kyoto Univ)
Eto, S. (Nikon Corp.)
Moritani, Y. (Kyoto Univ.)
Nakajima, Y. (中島分光)

SPIE paper (7014-27-iwamuro.ps.gz, 6.9MB)

SPIE presentation (7014-27-iwamuro.ppt, 17MB)

FMOS specifications

Wavelength 0.9～1.8μm
Field of view 30'φ
Fiber diameter 1.2"φ
400 multiplicity
OH-airglow suppression
Spectral resolution
　High disp. mode:2200
　Low disp. mode : 500
Limiting magnitude
　(1h integration, S/N=5)
　J-band 22.3mag
　H-band 20.9mag

IRS optical layout
Echidna

PFU
in case of emergency

IRS1
IRS2
　

First Light

J_long (1.13-1.35μm)
H_short (1.40-1.60μm)
● Spine configuration is imperfect.
● Airglow mask is not adjusted.
● Exact focus position should be confirmed.
　

Blackbody test

Light path
Light path
● Black body source (1000℃)
● Cassegrain hole → Corrector → F/2 filer → F/5 fiber → IRS
　　　15 Lenses + 6 Mirrors + 2 Fibers + 1 Grating + 1 Filter

J_long (1.13-1.35μm)
H_short (1.40-1.60μm)
● Continuum + Mask pattern
● 10 subsets × 20 fibsers
● FWHM: 5 pixels (optical aberration: 2 pixels)
● Pitch: ～10 pixels
・ Mask has not been blackened yet.

closeup view
Airglow mask

Wavelength dependent efficiency
● Typical efficiency: 21% (max: 30%), including Q.E. of detector
　　(assuming a conversion factor of 2.1 electroms/ADU)
● Rough estimation: 0.96⁽¹⁵⁺²⁾x 0.98⁶x 0.90³ = 0.31
● Almost the same efficiency as IRS2
・ 1.4μm absorption originates with silica material

Distribution of relative efficiencies
Ratio of relative efficiencies
● Relative efficiency is distributed within factor 2
● Typical wavelength dependency < 10%
　

Bright Star

Defocused image of a bright star
● Meaured efficiency is 11% (max may be 16%)
● Factor ～2 fainter compared to the BB measurement
　

Blackbody Source

Surface Brightness of the Blackbody Source
● Flux is factor 1.6 higher than expected !
● 21% / 1.6 x 0.85 (Sky & Primary) = 11%
　

Wavelength Calibration

Extracted and distortion corrected airglow spectra

Airglow (@J-long band)

Airglow (@H-short band)

Airglow (@H-long band)

Pixel - Wavelength relation
● Wavelength[μm] = 1.373 + 1.102e-4 pix - 1.314e-9 pix² - 5.402e-14 pix³
　　　 (1σ～ 1Å ～ 1pixel)
● J-short image is required to determine the function
　　for the full wavelength range.
　

Airglow Mask

Extracted and distortion corrected blackbody spectra

Blackbody (@J-long band)

Blackbody (@H-short band)

Blackbody (@H-long band)
● Several vending masks should be removed.
　

Detector

Conversion Factor

Count image
Noise image

Conversion Factor map
Count - Noise relation

Conversion Factor
Linearity
● Conversion Factor = 2.57 electrons/ADU (average)
　　　　　　　　　　　～1.9 electrons/ADU (mode)
● Linearity : Correction is not needed below ～40000ADU.
　　　　　　　4th order correction is effective above 40000ADU.
　(the gain of on-chip amp may change during the first several read out...)
　

Optical Alignment

Mosaic Grating
Mosaic Grating Adjustment
● It takes 30-60min to align the gratings.
● Long term stability has not been confirmed yet.

All Observation Modes

J short (0.90 - 1.13μm)
J long (1.12 - 1.35μm)

H short (1.40 - 1.60μm)
H long (1.60 - 1.80μm)

Low resolution (0.90 - 1.80μm)
(This image was taken before the final vertical position adjustment.)
● 3 fibers are out of the images.
● Optical alignment is almost completed.
　

Raster scan

Low resolution (0.90 - 1.80μm)
Extracted 1-D spectra (0.90 - 1.80μm)

5x5=25 0-D raster data
Error map

Low resolution (0.90 - 1.80μm)
15.1mag (0.90 - 1.80μm)
● Typical spine error ～0.2".
● 15mag, 60sec ⇒ S/N=5 (caused by high background).
　

Total efficiency

High resolution (1.60 - 1.80μm)
5x5=25 0-D raster data
(bad seeing!)

Count - mag diagram
Total efficiency (1.60 - 1.80μm)
Blue(bright) ⇒ Red(faint)
● Typical total efficiency @1.6μm: ～10%.
● Somewhat worse in the J-band (should be measured again).
　

Mask pattern

　list of masked airglow-lines

Summary

● System efficiency : typ. 11% - max.16% (conversion factor 2.1)
　　　　　　　　　　 typ. 9% - max.13% (conversion factor 2.6)
● Airglow Mask : should be moidfied after the check by real airglow lines.
● Mosaic grating : unstable?
● 3 fibers are out of the images.
● Optical alignment is almost completed.

IRS optical layout	Echidna
	FMOS specifications Wavelength 0.9～1.8μm Field of view 30'φ Fiber diameter 1.2"φ 400 multiplicity OH-airglow suppression Spectral resolution 　High disp. mode:2200 　Low disp. mode : 500 Limiting magnitude 　(1h integration, S/N=5) 　J-band 22.3mag 　H-band 20.9mag
PFU	in case of emergency
IRS1	IRS2

First Light
J_long (1.13-1.35μm)	H_short (1.40-1.60μm)
● Spine configuration is imperfect. ● Airglow mask is not adjusted. ● Exact focus position should be confirmed.

Blackbody test
Light path	Light path
● Black body source (1000℃) ● Cassegrain hole → Corrector → F/2 filer → F/5 fiber → IRS 　　　15 Lenses + 6 Mirrors + 2 Fibers + 1 Grating + 1 Filter
J_long (1.13-1.35μm)	H_short (1.40-1.60μm)
● Continuum + Mask pattern ● 10 subsets × 20 fibsers ● FWHM: 5 pixels (optical aberration: 2 pixels) ● Pitch: ～10 pixels ・ Mask has not been blackened yet.
closeup view	Airglow mask
Wavelength dependent efficiency
● Typical efficiency: 21% (max: 30%), including Q.E. of detector 　　(assuming a conversion factor of 2.1 electroms/ADU) ● Rough estimation: 0.96⁽¹⁵⁺²⁾x 0.98⁶x 0.90³ = 0.31 ● Almost the same efficiency as IRS2 ・ 1.4μm absorption originates with silica material
Distribution of relative efficiencies	Ratio of relative efficiencies
● Relative efficiency is distributed within factor 2 ● Typical wavelength dependency < 10%

Bright Star
Defocused image of a bright star
● Meaured efficiency is 11% (max may be 16%) ● Factor ～2 fainter compared to the BB measurement

Blackbody Source
Surface Brightness of the Blackbody Source
● Flux is factor 1.6 higher than expected ! ● 21% / 1.6 x 0.85 (Sky & Primary) = 11%

Wavelength Calibration
Extracted and distortion corrected airglow spectra
Airglow (@J-long band)
Airglow (@H-short band)
Airglow (@H-long band)
Pixel - Wavelength relation
● Wavelength[μm] = 1.373 + 1.102e-4 pix - 1.314e-9 pix² - 5.402e-14 pix³ 　　　 (1σ～ 1Å ～ 1pixel) ● J-short image is required to determine the function 　　for the full wavelength range.

Airglow Mask
Extracted and distortion corrected blackbody spectra
Blackbody (@J-long band)
Blackbody (@H-short band)
Blackbody (@H-long band)
● Several vending masks should be removed.

Detector
Conversion Factor
Count image	Noise image
Conversion Factor map	Count - Noise relation
Conversion Factor	Linearity
● Conversion Factor = 2.57 electrons/ADU (average) 　　　　　　　　　　　～1.9 electrons/ADU (mode) ● Linearity : Correction is not needed below ～40000ADU. 　　　　　　　4th order correction is effective above 40000ADU. 　(the gain of on-chip amp may change during the first several read out...)

Optical Alignment
Mosaic Grating	Mosaic Grating Adjustment
● It takes 30-60min to align the gratings. ● Long term stability has not been confirmed yet.
All Observation Modes
J short (0.90 - 1.13μm)	J long (1.12 - 1.35μm)
H short (1.40 - 1.60μm)	H long (1.60 - 1.80μm)
Low resolution (0.90 - 1.80μm) (This image was taken before the final vertical position adjustment.)
● 3 fibers are out of the images. ● Optical alignment is almost completed.

Raster scan
Low resolution (0.90 - 1.80μm)	Extracted 1-D spectra (0.90 - 1.80μm)
5x5=25 0-D raster data	Error map
Low resolution (0.90 - 1.80μm)	15.1mag (0.90 - 1.80μm)
● Typical spine error ～0.2". ● 15mag, 60sec ⇒ S/N=5 (caused by high background).

Total efficiency
High resolution (1.60 - 1.80μm)	5x5=25 0-D raster data (bad seeing!)
Count - mag diagram	Total efficiency (1.60 - 1.80μm) Blue(bright) ⇒ Red(faint)
● Typical total efficiency @1.6μm: ～10%. ● Somewhat worse in the J-band (should be measured again).

Mask pattern





list of masked airglow-lines
Summary
● System efficiency : typ. 11% - max.16% (conversion factor 2.1) 　　　　　　　　　　 typ. 9% - max.13% (conversion factor 2.6) ● Airglow Mask : should be moidfied after the check by real airglow lines. ● Mosaic grating : unstable? ● 3 fibers are out of the images. ● Optical alignment is almost completed.