A CMOS imager hybridized to an avalanche multiplied film

Takiguchi, Yuichi; Maruyama, Hirotaka; Kosugi, M.; Andoh, Fumihiko; Kato, Tsutomu; Tanioka, Kenkichi; Yamazaki, Junichi; Tsuji, Kiichiro; Kawamura, T.

doi:10.1109/16.628837

Cited by 40 publications

(28 citation statements)

References 2 publications

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“…It is known as an amorphous selenium (a-Se) high-gain avalanche rushing photoconductor (HARP) photosensor [15,16]. However, due to the high electric field (10 8 V/m) required for avalanche multiplication in a-Se [17], its use is currently restricted to electron beam readout in a vacuum pick-up tube, and it would be difficult to adopt it in solid-state imaging devices. Therefore, much effort has been expended on overcoming the problems [18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 98%

Photocurrent multiplication in Ga2O3/CuInGaSe2 heterojunction photosensors

Kikuchi¹,

Imura²,

Miyakawa³

et al. 2015

Sensors and Actuators A: Physical

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Section: Introductionmentioning

confidence: 98%

Photocurrent multiplication in Ga2O3/CuInGaSe2 heterojunction photosensors

Kikuchi¹,

Imura²,

Miyakawa³

et al. 2015

Sensors and Actuators A: Physical

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“…This has been demonstrated experimentally in a solid-state optical sensor incorporating a HARP layer. 25 Hence in our proposed detector a high E Se (> 80 V/µm) is needed to achieve good γ even when avalanche is not needed in some clinical applications (e.g. radiography).…”

Section: Optical Blurmentioning

confidence: 99%

Indirect flat-panel detector with avalanche gain

et al. 2004

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A new concept -an indirect flat-panel detector with avalanche gain -for low dose x-ray imaging has been proposed. The detector consists of an amorphous selenium (a-Se) photoconductor optically coupled to a structured cesium iodide (CsI) scintillator. Under an electric field E Se , the a-Se is sensitive to light and converts the optical photons emitted from CsI into electronic signal. These signals can be stored and read out in the same fashion as in existing flat-panel detectors. When E Se is increased to > 90 V/µm, avalanche multiplication occurs. The avalanche gain ranges between 1-800 depending on E Se and the thickness of the a-Se layer d Se . The avalanche a-Se photoconductor is referred to as HARP (High-gain Avalanche Rushing amorphous Photoconductor). A cascaded linear system model for the proposed detector was developed in order to determine the optimal CsI properties and avalanche gain for different x-ray imaging applications. Our results showed that x-ray quantum noise limited performance can be achieved at the lowest exposure level necessary for fluoroscopy (0.1 µR) and mammography (0.1 mR) with a moderate avalanche gain of 20 (d = 1-2 µm). A laboratory test system using an existing HARP tube optically coupled (through a lens) to a CsI layer was built and the advantage of avalanche gain in overcoming electronic noise was demonstrated experimentally. One of the advantages of the avalanche gain is that it will permit the use of high resolution (HR) CsI (which due to its low light output has not previously been used in flat-panel detectors) to improve DQE at high spatial frequencies.

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“…Due to its highly sensitive photoconducting property, a-Se has been widely used as a photoconversion layer in solid state image sensors [2], X-ray image detectors [3], and High-gain Avalanche Rushing amorphous Photoconductor (HARP) tubes [4]. Although HARP tubes provide highly sensitive property allowing their use in low-light environments, they cannot be used for practical image sensing because they require a vacuum space for electron beam scanning and their power consumption is large due to a thermionic electron emitter.…”

Section: Introductionmentioning

confidence: 99%