Functional imaging techniques like positron emission tomography (PET) are an essential tool in an aging society. despite impressive advances in microelectronics, photodetectors and scintillation materials, PET is stil...
Functional imaging techniques like positron emission tomography (PET) are an essential tool in an aging society. despite impressive advances in microelectronics, photodetectors and scintillation materials, PET is still awaiting a breakthrough in terms of reduced cost and increased performance. Large potential is seen in ultraprecise time-of-flight (TOF), aiming at coincidence time resolutions (CTRs) better than 30 ps. However, state-of-the-art TOF-PET systems are still far away from this goal, achieving typical CTRs of 214 ps (FWHM). Several proposals have been put forth, whereas the most promising is to use prompt photon emission, e.g. Cherenkov radiation in BGO crystals, which are cheap to produce, thus contributing to drastic cost cutting. However, Cherenkov detection is challenging due to its limited photon yield, which in turn requires a very high photon detection efficiency (PdE), low dark count rate (dCR) and extremely fast and innovative electronic readout schemes. recent analog silicon photomultipliers (aSiPMs) meet the first two targets, but not the *** the digilog project we envisage to unite the best of these two worlds, combining high PdE, low dCR and an exceptional SPTR. To reach this goal, we will segment state-of-the-art aSiPMs into smaller clusters, called µSiPMs. A balanced segmentation of the electronic readout will make it possible to efficiently detect the first scintillation and Cherenkov photons, with a manageable granularity at system level. The µSiPM signals will feature photon-density time walk correction and photon counting. We envision to create 3d-stacked sensors where the electronics will be housed in a CMOS bottom-tier and the µSiPMs in the top-tier chip. Preliminary measurements on first µSiPM test-structures already reached PdE anddCR close to their commercial counterparts, while an SPTR of 25 ps FWHM, close to our sub-20 ps goal, has been achieved.
Wetland ecosystems have complex habitat characteristics due to the wetland existing between lands and water bodies, however, satellite remote sensing images have normally mixed pixels because of their spectral charact...
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ISBN:
(纸本)9781424473014
Wetland ecosystems have complex habitat characteristics due to the wetland existing between lands and water bodies, however, satellite remote sensing images have normally mixed pixels because of their spectral characteristics of the riverine surface feature, and it is very difficult to extract the specific information of aquatic ecosystems. Hence satellite remote sensing images are hardly to match the demanding from scientists for their geoinformation researches in wetland investigation with a higher spatial accuracy. Unmanned airship low-altitude remote sensing system can resolve this technique problem. recentadvances in photo-geometry and relational technologies have facilitated the use of inexpensive digital cameras with the airborne remote sensing. And the ability of an airship would be enable it to obtain high-quality spatial images at a very high resolution by utilizing low-cost imaging instruments such as CCd cameras. due to few landmarks existing within the wetland areas, we set artificially signs as the control points in the study area. In this study, we obtained the scanned high-resolution images (with the spatial accuracy of 0.13m in a grid) using the unmanned airship platform in the Honghe National Nature Reserve (HNNR) located in the Northeast portion of the Sanjiang Plain. Using the software -Unmanned Aerial Vehicle (UAV) CCd Image Processing System, we have mosaic automatically the aerial photographs, and we also have mosaic artificially the images used the software ENVI 4.3 based on corresponding image points between adjacent images. The study results indicated that the auto-processing method relatively was more efficient image processing however with a lower accuracy (with 4 pixels as the RMS error). It meets a demand of the large amount of data process and a relatively lower accuracy. The artificial process method relatively has a higher accuracy (less 2 pixels as the RMS error) however time-consuming, which may be applied to the image process wit
The IceCube Neutrino Observatory deployed 5160 digital optical modules (dOMs) on 86 cables, called strings, in a cubic kilometer of deep glacial ice below the geographic South Pole. These record the Cherenkov light of...
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