The Extreme Ultraviolet Imager (EUI) on-board the Solar Orbiter mission will provide image sequen... more The Extreme Ultraviolet Imager (EUI) on-board the Solar Orbiter mission will provide image sequences of the solar atmosphere at selected spectral emission lines in the extreme and vacuum ultraviolet. For the two Extreme Ultraviolet (EUV) channels of the EUI instrument, low noise and radiation tolerant detectors with low power consumption and high sensitivity in the 10-40 nm wavelength range are required to achieve the science objectives. In that frame, a dual-gain 10 µm pixel pitch back-thinned 1k x 1k Active Pixel Sensor (APS) CMOS prototype has been tested during the preliminary development phase of the instrument, to validate the pixel design, the expected EUV sensitivity and noise level, and the capability to withstand the mission radiation environment. Taking heritage of this prototype, the detector architecture has been improved and scaled up to the required 3k x 3k array. The dynamic range is increased, the readout architecture enhanced, the power consumption reduced, and the...
As interactive services require more bandwidth, high speed access networks must follow this trend... more As interactive services require more bandwidth, high speed access networks must follow this trend. Although a Hybrid Fiber Coax (HFC) system provides a large bandwidth, many problems occur due to the accumulation of the ingress and impulse noise. In this paper the properties of the ingress and impulse noise will be explained based on a measurement campaign on different networks. The most striking result of the measurement campaign is the large dynamic and time- dependent behavior of the ingress noise. This dynamic behavior is an important factor in designing an upstream communication system. We show that for this reason optimized receivers will contain adaptive equalizers. This is illustrated by the performance analysis of a TDMA and an OFDM-CDMA system. Both systems are compared under the same environment. The results of this comparison shows how both can obtain the same performance. Considering the implications of both the TDMA and the CDMA system when using an equalizer in the he...
UV, Optical, and IR Space Telescopes and Instruments, 2000
ABSTRACT A gallium arsenide photoconductive detector, which is sensitive in the far-infrared wave... more ABSTRACT A gallium arsenide photoconductive detector, which is sensitive in the far-infrared wavelength range from approximately 60 micrometers to 300 micrometers , offers the advantage of extending considerably the long wavelength cut-off of presently available photodetectors. FIRGA is an ESA sponsored GaAs detector development program which is approaching completion. The FIRGA study is intended to prepare the technology for large 2D GaAs detector arrays for far-infrared astronomy. The primary goal of the development is the preparation of a monolithic 32 element demonstrator array module with associated cryogenic read-out electronics. Continuous progress in material research has led to the production of pure and doped n-type GaAs layers using liquid phase epitaxy. We prepared sample detectors from those materials and investigated their electrical and infrared characteristics. Finally, a multi-layer structured detector device was manufactured. The 4 X 8 element array configuration is defined by sawing a split pattern into the layers with pixel size 1 mm X 1 mm. The device is back illuminated. The 32 pixels are connected to two cryogenic read-out electronics chips mounted close-by. Results of the initial detector performance tests are reported. We determined dark current, responsivity and response transients. Ongoing development activities will concentrate on material research, i.e. the production of n-GaAs layers of ultra-high purity and those with improved FIR characteristics using new centrifugal techniques for material growth.
ABSTRACT PACS covers the wavelength range 80-210 micrometers in spectrometric and photometric ima... more ABSTRACT PACS covers the wavelength range 80-210 micrometers in spectrometric and photometric imaging modes. The long wavelength camera is a 16 X 25 pixel array of stressed Ge:Ga detectors. In order to demonstrate the feasibility of such a large array, one of the 25 linear arrays was manufactured. It consists of 16 elements of 1.5 mm(superscript 3) each separated by ceramic plungers and stressed by one single mechanism. As preamplifier a dedicated CMOS circuit was developed, based on similar circuits successfully operating in ISO's photometer. In particular, it was intended to increase the gain of the CRE in order to minimize the debiasing effects on the low bias operated detectors. Two complete linear demonstrator arrays were manufactured and independently tested under various low background conditions in a 1.7 K environment at MPIA and MPE. The feasibility of the concept chosen was demonstrated in several functional tests. Valuable experience was gained to guide the development of the next generation of CREs and arrays.
We report on a micromachined silicon chip that is capable of providing a high-throughput function... more We report on a micromachined silicon chip that is capable of providing a high-throughput functional assay based on calorimetry. A prototype twin microcalorimeter based on the Seebeck effect has been fabricated by IC technology and micromachined postprocessing techniques. A biocompatible liquid rubber membrane supports two identical 0.5 X 2 cm2 measurement chambers, situated at the cold and hot junction of a 666-junction aluminum/p+-polysilicon thermopile. The chambers can house up to 106 eukaryotic cells cultured to confluence. The advantage of the device over microcalorimeters on the market, is the integration of the measurement channels on chip, rendering microvolume reaction vessels, ranging from 10 to 600 (mu) l, in the closest possible contact with the thermopile sensor (no springs are needed). Power and temperature sensitivity of the sensor are 23 V/W and 130 mV/K, respectively. The small thermal inertia of the microchannels results in the short response time of 70 s, when fil...
International Conference on Solid State Sensors and Actuators, 1997
This paper reports on a novel micromachining technique for fabricating rubber membranes with an a... more This paper reports on a novel micromachining technique for fabricating rubber membranes with an area of tens of square centimetres and a thickness of a few micrometers. In the basic technique a silicon wafer is spincoated with liquid rubber, bonded to a second (sacrificial) wafer and locally thinned out by anisotropical wet etching. The potential of the technique is highlighted
The Extreme Ultraviolet Imager (EUI) on-board the Solar Orbiter mission will provide image sequen... more The Extreme Ultraviolet Imager (EUI) on-board the Solar Orbiter mission will provide image sequences of the solar atmosphere at selected spectral emission lines in the extreme and vacuum ultraviolet. For the two Extreme Ultraviolet (EUV) channels of the EUI instrument, low noise and radiation tolerant detectors with low power consumption and high sensitivity in the 10-40 nm wavelength range are required to achieve the science objectives. In that frame, a dual-gain 10 µm pixel pitch back-thinned 1k x 1k Active Pixel Sensor (APS) CMOS prototype has been tested during the preliminary development phase of the instrument, to validate the pixel design, the expected EUV sensitivity and noise level, and the capability to withstand the mission radiation environment. Taking heritage of this prototype, the detector architecture has been improved and scaled up to the required 3k x 3k array. The dynamic range is increased, the readout architecture enhanced, the power consumption reduced, and the...
As interactive services require more bandwidth, high speed access networks must follow this trend... more As interactive services require more bandwidth, high speed access networks must follow this trend. Although a Hybrid Fiber Coax (HFC) system provides a large bandwidth, many problems occur due to the accumulation of the ingress and impulse noise. In this paper the properties of the ingress and impulse noise will be explained based on a measurement campaign on different networks. The most striking result of the measurement campaign is the large dynamic and time- dependent behavior of the ingress noise. This dynamic behavior is an important factor in designing an upstream communication system. We show that for this reason optimized receivers will contain adaptive equalizers. This is illustrated by the performance analysis of a TDMA and an OFDM-CDMA system. Both systems are compared under the same environment. The results of this comparison shows how both can obtain the same performance. Considering the implications of both the TDMA and the CDMA system when using an equalizer in the he...
UV, Optical, and IR Space Telescopes and Instruments, 2000
ABSTRACT A gallium arsenide photoconductive detector, which is sensitive in the far-infrared wave... more ABSTRACT A gallium arsenide photoconductive detector, which is sensitive in the far-infrared wavelength range from approximately 60 micrometers to 300 micrometers , offers the advantage of extending considerably the long wavelength cut-off of presently available photodetectors. FIRGA is an ESA sponsored GaAs detector development program which is approaching completion. The FIRGA study is intended to prepare the technology for large 2D GaAs detector arrays for far-infrared astronomy. The primary goal of the development is the preparation of a monolithic 32 element demonstrator array module with associated cryogenic read-out electronics. Continuous progress in material research has led to the production of pure and doped n-type GaAs layers using liquid phase epitaxy. We prepared sample detectors from those materials and investigated their electrical and infrared characteristics. Finally, a multi-layer structured detector device was manufactured. The 4 X 8 element array configuration is defined by sawing a split pattern into the layers with pixel size 1 mm X 1 mm. The device is back illuminated. The 32 pixels are connected to two cryogenic read-out electronics chips mounted close-by. Results of the initial detector performance tests are reported. We determined dark current, responsivity and response transients. Ongoing development activities will concentrate on material research, i.e. the production of n-GaAs layers of ultra-high purity and those with improved FIR characteristics using new centrifugal techniques for material growth.
ABSTRACT PACS covers the wavelength range 80-210 micrometers in spectrometric and photometric ima... more ABSTRACT PACS covers the wavelength range 80-210 micrometers in spectrometric and photometric imaging modes. The long wavelength camera is a 16 X 25 pixel array of stressed Ge:Ga detectors. In order to demonstrate the feasibility of such a large array, one of the 25 linear arrays was manufactured. It consists of 16 elements of 1.5 mm(superscript 3) each separated by ceramic plungers and stressed by one single mechanism. As preamplifier a dedicated CMOS circuit was developed, based on similar circuits successfully operating in ISO's photometer. In particular, it was intended to increase the gain of the CRE in order to minimize the debiasing effects on the low bias operated detectors. Two complete linear demonstrator arrays were manufactured and independently tested under various low background conditions in a 1.7 K environment at MPIA and MPE. The feasibility of the concept chosen was demonstrated in several functional tests. Valuable experience was gained to guide the development of the next generation of CREs and arrays.
We report on a micromachined silicon chip that is capable of providing a high-throughput function... more We report on a micromachined silicon chip that is capable of providing a high-throughput functional assay based on calorimetry. A prototype twin microcalorimeter based on the Seebeck effect has been fabricated by IC technology and micromachined postprocessing techniques. A biocompatible liquid rubber membrane supports two identical 0.5 X 2 cm2 measurement chambers, situated at the cold and hot junction of a 666-junction aluminum/p+-polysilicon thermopile. The chambers can house up to 106 eukaryotic cells cultured to confluence. The advantage of the device over microcalorimeters on the market, is the integration of the measurement channels on chip, rendering microvolume reaction vessels, ranging from 10 to 600 (mu) l, in the closest possible contact with the thermopile sensor (no springs are needed). Power and temperature sensitivity of the sensor are 23 V/W and 130 mV/K, respectively. The small thermal inertia of the microchannels results in the short response time of 70 s, when fil...
International Conference on Solid State Sensors and Actuators, 1997
This paper reports on a novel micromachining technique for fabricating rubber membranes with an a... more This paper reports on a novel micromachining technique for fabricating rubber membranes with an area of tens of square centimetres and a thickness of a few micrometers. In the basic technique a silicon wafer is spincoated with liquid rubber, bonded to a second (sacrificial) wafer and locally thinned out by anisotropical wet etching. The potential of the technique is highlighted
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Papers by Lou Hermans