Performance of the CFH12K: a 12K by 8K CCD mosaic camera for the CFHT prime focus

Cuillandre, Jean-Charles; Starr, Barry Michael; Isani, Sidik

doi:10.1117/12.395465

Cited by 43 publications

(32 citation statements)

References 2 publications

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“…As reported by CFHT [2] , the detectors have an average readout noise of 5 electrons (with a correlated double sampling time of 1 µs per dwell), a dark current of only ~1 electron per minute per pixel at -89 deg. C, and a peak quantum efficiency of up to 90% in R band.…”

Section: Instrument Overviewmentioning

confidence: 98%

“…The remaining three are made from high-resistivity bulk silicon (Hi-Rho) and are grouped in one corner of the mosaic. The Hi-Rho devices have a higher QE (up to 20% more) in the red part of the spectrum, and produce less fringing than the EPI devices due to their larger thickness [2] .…”

Section: Instrument Overviewmentioning

confidence: 99%

“…Although the CCDID-20 CCDs have two outputs, some of the devices have only one functional [2] . Since readout must be synchronous, all CCDs must therefore be read through a single output.…”

Section: Readout Electronics and Softwarementioning

confidence: 99%

“…The cooling of the camera was provided by an 8-liter liquid nitrogen tank. There was also an Auxiliary Control Electronic module, which served as interface to the shutter, filter wheel and temperature control, in coordination with the CCD controllers [2] .…”

Section: Instrument Overviewmentioning

confidence: 99%

“…Our total delivered image quality goal, 2 arcsec, maps to 2 pixels (at 1 arcsec/pixel) [4] , whereas the typical 0.6 arcsec FWHM images on CFHT mapped to 3 pixels at their 0.2 arcsec/pixel plate scale [2] . In combination this placed a tighter requirement on flatness of the CCD surfaces.…”

Section: Focal Plane Co-planaritymentioning

confidence: 99%

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The 12K×8K CCD mosaic camera for the Palomar Transient Factory

et al. 2008

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The Palomar Transient Factory is an automated wide-field survey facility dedicated to identifying a wide range of transient phenomena. Typically, a new 7.5 square degree field will be acquired every 90 seconds with 66% observing efficiency, in g' band when the sky is dark, or in R band when the moon is up. An imaging camera with a 12Kx8K mosaic of MIT/LL CCDs, acquired from CFHT, is being repackaged to fit in the prime focus mounting hub of the Palomar 48-inch Oschin Schmidt Telescope. We discuss how we have addressed the broad range of issues presented by this application: faster CCD readout to improve observing efficiency, a new cooling system to fit within the constrained space, a low impact shutter to maintain reliability at the fast observing cadence, a new filter exchange mechanism, and the field flattener needed to correct for focal plane curvature. The most critical issue was the tight focal plane alignment and co-planarity requirements created by the fast beam and coarse plate scale. We built an optical profilometer system to measure CCDs heights and tilts with 1 µm RMS accuracy.

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Section: Instrument Overviewmentioning

confidence: 98%

Section: Instrument Overviewmentioning

confidence: 99%

“…Although the CCDID-20 CCDs have two outputs, some of the devices have only one functional [2] . Since readout must be synchronous, all CCDs must therefore be read through a single output.…”

Section: Readout Electronics and Softwarementioning

confidence: 99%

Section: Instrument Overviewmentioning

confidence: 99%

Section: Focal Plane Co-planaritymentioning

confidence: 99%

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The 12K×8K CCD mosaic camera for the Palomar Transient Factory

et al. 2008

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GaBoDS: The Garching‐Bonn Deep Survey

Erben¹,

et al. 2005

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Aims. An interesting question of contemporary cosmology concerns the relation between the spatial distribution of galaxies and dark matter, which is thought to be the driving force behind the structure formation in the Universe. In this paper, we measure this relation, parameterised by the linear stochastic bias parameters, for a range of spatial scales using the data of the Garching-Bonn Deep Survey (GaBoDS). Methods. The weak gravitational lensing effect is used to infer matter density fluctuations within the field-of-view of the survey fields. This information is employed for a statistical comparison of the galaxy distribution to the total matter distribution. The result of this comparison is expressed by means of the linear bias factor b, the ratio of density fluctuations, and the correlation factor r between density fluctuations. The total galaxy sample is divided into three sub-samples using R-band magnitudes and the weak lensing analysis is applied separately for each sub-sample. Together with the photometric redshifts from the related COMBO-17 survey we estimate the typical mean redshifts of these samples withz = 0.35, 0.47, 0.61, respectively. Results. Using a flat ΛCDM model with Ω m = 0.3, Ω Λ = 0.7 as fiducial cosmology, we obtain values for the galaxy bias on scales between 1 ≤ θ ap ≤ 20 . At 10 , the median redshifts of the samples correspond roughly to a typical comoving scale of 3, 5, 7 h −1 Mpc with h = 0.7, respectively. We find evidence for a scale-dependence of b. Averaging the measurements of the bias over the range 2 ≤ θ ap ≤ 19 yieldsb = 0.81 ± 0.11, 0.79 ± 0.11, 0.81 ± 0.11 (1σ), respectively. Galaxies are thus less clustered than the total matter on that particular range of scales (anti-biased). As for the correlation factor r we see no scale-dependence within the statistical uncertainties; the average over the same range isr = 0.61 ± 0.16, 0.64 ± 0.18, 0.58 ± 0.19 (1σ), respectively. This implies a possible decorrelation between galaxy and dark matter distribution. An evolution of galaxy bias with redshift is not found, the upper limits are: ∆b 0.2 and ∆r 0.4(1σ).

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