NIFS Sensitivity Estimates

The following sensitivity table provides signal-to-noise ratios (S/N) of 5 per spectral pixel in one hour (6x600 seconds) on-source integration. They were estimated using the NIFS Integration Time Calculator (ITC) and the obtained S/N of 5 is the averaged S/N in the wavelength intervals. These values are for silver coatings on the telescope optics and NIFS on the up-looking port.  Observing conditions are 70%-ile image quality, 50%-ile cloud cover (photometric), 80%-ile water vapor column, 80%-ile sky background , and for an average airmass of 1.5. 

Although these ITC estimates are not far off the actual NIFS measurements, detailed calculations show some inconsistencies. Thus, these estimates are provided only for proposal preparation and are not meant to be absolute guides. Nonetheless, applicants should use the ITC to estimate the signal-to-noise ratio at the precise wavelengths of interest and/or over the entire band of interest. 

Following NIFS detector-related information was used in the above estimates.

• readout noise: Fowler sampling 16-16 ("Faint Object mode" = ~6 e- at 77K)
• detector gain: 2.8 e- / ADU
• saturation limit: ~48,000 ADU
• 1 IFU pixel = 0."04 X 0."10

Last update 2006-Jun-16; Inseok Song, Tom Geballe, & Brian Walls