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Comparison between bulk micromachined and CMOS x-ray detectors
Rocha, J. G.; Schabmueller, C. G. J.; Ramos, N. F.; Lanceros-Méndez, S.; Evans, A. G. R.; Wolffenbuttel, R. F.; Correia, J. H.This paper compares two x-ray detectors fabricated using two different technologies: one is based on a bulk micromachined silicon photodetector and the other is based on a standard CMOS photodetector. The working principle of the two detectors is similar: a scintillating layer of CsI:Tl is placed above the photodetector, so the x-rays are first converted into visible light (560nm) which is then converted into a...
CMOS x-rays detector array based on scintillating light guides
Rocha, J. G.; Ramos, N. F.; Lanceros-Méndez, S.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a pixel imaging array consisting in 400µm x 400µm photodiodes fabricated in CMOS technology. An array of scintillating CsI:Tl crystals is placed above the photodiodes. These crystals are encapsulated in aluminum walls, forming a light path that guides the visible light produced by the scintillating crystal into the photodiodes. In This way, the x-ray energy is first converted into visible l...
CMOS x-ray image sensor with pixel level A/D conversion
Rocha, J. G.; Ramos, N. F.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a pixel array for x-rays imaging consisting in 400 um x 400 um photodiodes fabricated in CMOS technology, with an A/D converter for each one. Above the photodiodes, an array of scintillating CsI:Tl crystals are placed. So, the x-ray energy is first converted to visible light by the scintillating crystals which is then detected by the photodiodes. The photocurrent produced by each photodiode...
Comparison between bulk micromachined and CMOS detectors for X-ray measurements
Rocha, J. G.; Schabmueller, C. G. J.; Ramos, N. F.; Lanceros-Méndez, S.; Moreira, M. V.; Evans, A. G. R.; Wolffenbuttel, R. F.; Correia, J. H.This paper compares two x-ray detectors fabricated using two different technologies: one is based on a bulk micromachined silicon photodetector and the other is based on a standard CMOS photodetector. The working principle of the two detectors is similar: a scintillating layer of CsI:Tl is placed above the photodetector, so the x-rays are first converted into visible light (560 nm) which is then converted into ...
CMOS X-ray imager for dental radiography
Ramos, N. F.; Rocha, J. G.; Lanceros-Méndez, S.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a 64 pixels X-ray imager architecture and fabrication process. The imager is composed by a 8×8 photodiodes array, fabricated in CMOS process, and an array of wells £lled with scintillating crystals. A thick-£lm of aluminum is etched in order to achieve square wells with 500 um depth. The wells are filled with CsI:Tl scintillating crystals and placed above the photodiodes. The scintillating ...
X-ray detector based on a bulk micromachined photodiode combined with a scintil...
Rocha, J. G.; Schabmueller, C. G. J.; Ramos, N. F.; Lanceros-Méndez, S.; Costa, Manuel F. M.; Evans, A. G. R.; Wolffenbuttel, R. F.; Correia, J. H.This paper reports the design, fabrication, assembly and testing of a x-ray detector based on a bulk micromachined photodiode (BMMPD) with a cavity filled with a scintillating crystal. The x-ray photons that reach the detector are first converted to visible light by the scintillating crystal. The visible light is then detected by the BMMPD, producing an electric current with value proportional to the incident x...
Small size sigma-delta analog to digital converter
Rocha, J. G.; Ramos, N. F.This report describes the analog to digital converter for an image sensor, implemented in a standard CMOS process. The image sensor, after coated with a scintillator material, can acquire x-rays images. Since it uses standard CMOS technology, the digital circuits of control and signal processing can be integrated into the same chip. The analog to digital convertion is based in a sigma delta approach, being impl...
CMOS X-rays microdetector based on scintillating light guides
Rocha, J. G.; Ramos, N. F.; Moreira, M. V.; Lanceros-Méndez, S.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a pixel imaging array consisting in 400 um x 400 um photodiodes fabricated in CMOS technology. Above the photodiodes, an array of scintillating CsI:Tl crystals are placed. The scintillating crystals are encapsulated in aluminum walls forming a light path to guide the produced visible light into the photodiodes. So, the x-ray energy is first converted into visible light which is then detec...
X-rays microdetectors based on an array of scintillators : a maskless process u...
Rocha, J. G.; Moreira, M. V.; Wolffenbuttel, R. F.; Ramos, N. F.; Lanceros-Méndez, S.; Correia, J. H.This paper describes a X-rays microdetector based on an array of wells filled with scintillator crystals. A thick-film of aluminum (500 um) is etched by Laser Ablation Technique (LAT) in order to achieve a square well with side of 100 um and 490 um deep vertical sidewalls. The aluminum thick-film was chosen because it is a good reflector in the visible range and for improving the number of photons collected by...
Xray detector based on bulk micromachined photodiode
Rocha, J. G.; Schabmueller, C. G. J.; Ramos, N. F.; Lanceros-Méndez, S.; Evans, A. G. R.; Wolffenbuttel, R. F.; Correia, J. H.This paper reports the design, fabrication, assembly and testing of a xray detector based on a bulk micromachined photodiode (BMMPD) with a cavity filled with a scintillating crystal. The xray photons that reach the detector are first converted to visible light by the scintillating crystal. The visible light is then detected by the BMMPD, producing an electric current whose value is proportional to the incident...
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