IRMS vs IRIS Sensitivity (to be improved. . . )
11/30/2010 Tokoku

Parameters
IRMS IRIS reference
Effective Collecting Area of TMT
[m2]
630 630 Hexagon with 1.44m across the corner x 492 = 662
630 from IRIS SPIE(2010)
Pixel Scale
[arcmin/pix]
0.06 (=60mas) 0.004 (=4mas) for imaging
0.05 (=50mas) for spectroscopy
TMT Instrumentation Handbook(2010)
IRIS SPIE(2010)
Strel Ratio 0.7@J, 0.81@H, 0.89@K SR is not used for this calculation.
Diffraction Limit
= Assumed Aperture(1)
[arcsec]
2.44&lambda/D
0.021"@J, 0.027"@H, 0.036"@K
2&lambda/D
0.017"?@J, 0.023"@H, 0.030"@K
IRIS SPIE(2010)
A point source fall on... 1x1 pix 5x5 pix@J, 7x7 pix@H, 8x8 pix@K
Assumed Encircled Energy inside Aperture(1) w/NFIRAOS wide-field mode for &Phi 120"
0.95@J, 0.95@H, 0.95@K
w/NFIRAOS narrow-field mode for &Phi 30"
0.9@J, 0.9@H, 0.9@K
TMT Instrument Handbook(2010)
Thruput Telescope (a) 0.91 (M1xM2xM3) 0.91 (M1xM2xM3) TMT Instrument Handbook(2010)
NIFIRAOS (b) 0.85 0.85 TMT Insrtument Handbook(2010)
OIWFS (c) 0.986@J, 0.986@H, 0.988@K TMT Insrtument Handbook(2010)
ADC (d) 0.960@J, 0.960@H, 0.968@K TMT Insrtument Handbook(2010)
Imager (e) 0.45@J, 0.44@H, 0.33@K
(Filters=0.9, QE=0.8)
0.540@J, 0.62@H, 0.50@K MOSFIRE DDR(2007)
TMT Instrument Handbook(2010)
IMAGER TOTAL
(a)x(b)x(c)x(d)x(e)
0.348@J, 0.340@H, 0.255@K 0.395@J, 0.454@H, 0.370@K
Grating/Slicer (f) 0.65@J, 0.75@H, 0.83@K 0.410@J, 0.588@H, 0.529@K MOSFIRE DDR(2007)
TMT Instrument Handbook(2010)
SPECTROGRAPH TOTAL
(a)x(b)x(c)x(d)x(f)
0.2262@J, 0.255@H, 0.21@K 0.300@J, 0.431@H, 0.40@K TMT Instrument Handbook(2010)
Readout Noise 5 e-
(H2RG)
5 e-
(H4RG)
MOSFIRE DDR(2007)
IRIS SPIE(2010)
Dark 0.03 e-/s
(H2RG)
0.006 e-/s
(H4RG)
MOSFIRE DDR(2007)
IRIS SPIE(2010)
Assumed Background Sky brightness@MaunaKea
J=16.1mag, H=13.8mag, K=14.8mag
Thermal form Atmosohere: T=258K, &epsilon =0.1
Zodiacal light: T=5800K, &epsilon=3e-14
Thermal from Telescope: T=73K, &epsilon=0.02
Thermal from NFIRAOS+IRIS: T=243K, &epsilon=0.01
Gemini Homepage
IRIS SPIE(2010)
Exposure Time
[sec]
18000 (900s x 20) 18000 (900s x 20) IRIS SPIE(2010)
Spectral Resolution 5000 4000 MOSFIRE DDR(2007)
Imaging IRIS imaging sensitivity estimation from SPIE(2010) Spectrograph IRIS spectroscopy sensitivity from SPIE(2010)