Soft-X-ray CCD imagers for AXAF

Burke, Barry E.; Gregory, J. A.; Bautz, M. W.; Prigozhin, G.; Kissel, S.; Kosicki, B. B.; Loomis, A.H.; Young, Douglas

doi:10.1109/16.628815

Cited by 95 publications

(56 citation statements)

References 16 publications

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“…Since in many previous applications 4,6,9 it has been acceptable to reduce dark current by cooling to the temperature range of -60 to -100°C, many of the CCDs from Lincoln have not required the improvements implemented in this paper, namely MBE backside treatment or dithered clocking. In these lower temperature ranges the readout noise is larger than the dark current.…”

Section: Operating Temperature Versus Dark Currentmentioning

confidence: 99%

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Low dark current, back-illuminated charge coupled devices

et al. 2009

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Abstract:Dark current for back-illuminated (BI) charge-coupled-device (CCD) imagers at Lincoln Laboratory has historically been higher than for front-illuminated (FI) detectors. This is presumably due to high concentrations of unpassivated dangling bonds at or near the thinned back surface caused by wafer thinning, inadequate passivation and low quality native oxide growth. The high dark current has meant that the CCDs must be substantially cooled to be comparable to FI devices. The dark current comprises three components: frontside surface-state, bulk, and back surface. We have developed a backside passivation process that significantly reduces the dark current of BI CCDs. The BI imagers are passivated using molecular beam epitaxy (MBE) to grow a thin heavily boron-doped layer, followed by an annealing step in hydrogen. The frontside surface state component can be suppressed using surface inversion, where clock dithering reduces the frontside dark current below the bulk. This work uses surface inversion, clock dithering and comparison between FI and BI imagers as tools to determine the dark current from each of the components. MBE passivated devices, when used with clock dithering, have dark current reduced by a factor of one hundred relative to ion-implant/laser annealed devices, with measured values as low as 10-14 pA/cm 2 at 20°C.

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Section: Operating Temperature Versus Dark Currentmentioning

confidence: 99%

“…The process consists of a thermal oxidation (35 nm dry oxidation) followed by a 25 keV BF 2 implantation and an 850°C furnace anneal to activate the dopant. This process was performed on CCDs using narrow (~1 mm wide) rim-thinned wafers 4 .…”

Section: Backside Illumination -Passivation Processesmentioning

confidence: 99%

Low dark current, back-illuminated charge coupled devices

et al. 2009

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“…A complete description can be found in [2]. Each CCD is a 1024x1026-pixel frame-transfer imager which is divided into four sectors.…”

Section: Ccd Characteristicsmentioning

confidence: 99%

“…The instrument consists of ten Charge Coupled Devices (CCDs) especially designed for efficient X-ray detection and spectroscopy [2]. Four of the front illuminated (FI) CCDs are arranged in a square array with each CCD tipped slightly to better approximate the curved focal surface of the Chandra Wolter type I mirror assembly.…”

Section: Introductionmentioning

confidence: 99%

Advanced CCD imaging spectrometer (ACIS) instrument on the Chandra X-ray Observatory

et al. 2003

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The ACIS instrument has been operating for three years in orbit, producing high quality scientific data on a wide variety of X-ray emitting astronomical objects. Except for a brief period at the very beginning of the mission when the CCDs were exposed to the radiation environment of the Outer van Allen Belts which resulted in substantial radiation damage to the front illuminated CCDs, the instrument has operated nearly flawlessly. The following report presents a description of the instrument, the current status of the instrument calibration and a few highlights of the scientific results obtained from the Guaranteed Observer Time.

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“…For both observations photons were collected using the Advanced CCD Imaging Spectrometer (ACIS; Burke et al (1997)), which has resolution ∆E/E ∼ 0.1 at 1 keV scaling as 1/ √ E over its 0.2-10 keV range. The pulsar was positioned on the back-illuminated S3 chip of the ACIS-S array, offset by 0 ′ .58 from the aim point, where the PSF is undersampled by the 0 ′′ .4920×0 ′′ .4920 CCD pixels.…”

Section: Observations Psr 0628-28mentioning

confidence: 99%

Chandra observations of two pulsars PSR 0628-28 and PSR 1813-36

Öğelman¹,

Tepedelenlioǧlu²

2004

Advances in Space Research

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PSR 0628-28 is an X-ray emitting radio pulsar which was observed with Advanced CCD Imaging Spectrometer (ACIS) on board Chandra on 2001 November 04 and on 2002 March 25 for 2000 s and 17000 s, respectively. The source countrate was 0.0111±0.0013cps. Making PSR 0628-28 to be the longest period X-ray emitting pulsar. The spectral distribution of counts can be described by several model fits. A blackbody fit yields a temperature kT = 2.69

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Soft-X-ray CCD imagers for AXAF

Cited by 95 publications

References 16 publications

Low dark current, back-illuminated charge coupled devices

Low dark current, back-illuminated charge coupled devices

Advanced CCD imaging spectrometer (ACIS) instrument on the Chandra X-ray Observatory

Chandra observations of two pulsars PSR 0628-28 and PSR 1813-36

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