Experiments such as CHORUS at CERN require the inspection of a large amount of nuclear emulsion plates exposed to particle beams. Rare events need to be found, measured and analysed. Their features are stored as grain...
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ISBN:
(纸本)0819432652
Experiments such as CHORUS at CERN require the inspection of a large amount of nuclear emulsion plates exposed to particle beams. Rare events need to be found, measured and analysed. Their features are stored as grains in microscopic dimensions in a three-dimensional stack of plates. A new, fully automatic immersion microscope system was developed for this purpose. It features high resolution, small depth of focus, large working distance, large field of view and synchronization of illumination and detector. An additional requirement is given by variations in the refraction index and in the relative thickness of immersion oil and emulsion. The approach used here is an imaging system based on a vario objective lens (variable oil immersion) with extreme numerical aperture, large working distance and wide field, combined with a matched high-aperture Koehler illuminator. The light source is a mercury are lamp, combined with a filter package for the g-line. It includes liquid crystal elements for synchronized shuttering and variable attenuation. The theoretical resolution is less than 1 micron in x, y, z within a volume of 0.5mm diameter (x, y) times 1 mm scanning depth (z) in all situations within a predefined index range (1.49 to 1.54). Three identical pieces of the system have been built. The experimentally measured resolution confirms the expectations and is better than 1 micron in all three dimensions. This is the result of a complex process of system design and manufacturing, unifying optical, opto-mechanical and optoelectronical contributions. This process spans from the early stages of feasibility and manufacturing up to the test and adjustment procedures. The three prototypes are operational since the fall of 1998 in the frame of the CHORUS project. Practical experience and application results are presented.
The proceedings contain 24 papers. The topics discussed include: integration design of endoscope with different viewing angles;ultra-compact hourglass lens for integrated cameras;testing and alignment of freeform base...
ISBN:
(纸本)9781628417449
The proceedings contain 24 papers. The topics discussed include: integration design of endoscope with different viewing angles;ultra-compact hourglass lens for integrated cameras;testing and alignment of freeform based multi-mirror telescopes;tolerancing an optical freeform surface: an optical fabricator's perspective;manufacture and analysis of a refractive surface with variable asphericity to model the human cornea;modeling and design of a multichannel chromatic aberration compensated imaging system;temperature-dependent refractive index measurements of L-BBH2 glass for the Subaru CHARIS integral field spectrograph;cryogenic refractive indices of S-LAH55, S-LAH55V, S-LAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14 glasses;temperature-dependent refractive index measurements of CaF2, Suprasil 3001, and S-FTM16 for the Euclid near-infrared spectrometer and photometer;design considerations for an unconventional infrared prism with a 90 degree ray deviation;and high-performance LED luminaire for sports hall.
Retinal examination using direct ophthalmoscope is preferred over other techniques for screening purposes because of its portability and high magnification, despite its power sustainability and cost issues. With incre...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Retinal examination using direct ophthalmoscope is preferred over other techniques for screening purposes because of its portability and high magnification, despite its power sustainability and cost issues. With increasing number of low-cost sustainable devices available in the market, it is important to assess the efficacy of the devices. We compared three devices - Arclight ophthalmoscope, a D-Eye attached to iPhone 6, and conventional ophthalmoscope Heine K180 - in terms of ease of examination, usage, field of view, color rendition, patient comfort, length of examination, and closeness to the eye. Two trained optometrists examined 26 undilated eyes and graded the ease of retinal examination, ease of use and assessed vertical cup:disc ratio (VCDR). Patients reported their comfort level in terms of glare produced by the light source, length of examination and closeness to the eye. The examiners had a good agreement for all assessments. Of 26 eyes, VCDR assessment was not possible in 10/ 26 (38.4%) of the examinations, in (3/26, 11.5%) examinations with Arclight, in 0/26 examinations with D-Eye. Ease of use score was higher for Arclight and D-Eye than Heine. D-Eye had a relatively larger field of view than other 2 devices. Heine ranked first in color rendition. The luminance level of the high-beam setting of Arclight was more than twice that of Heine and D-Eye. Despite that, the patients reported experiencing uncomfortable glare in Heine (14/26, 53.8%), significant glare with Arclight (16/26, 61.5%) and some/no glare with D-Eye. The examination time was shorter when using D-Eye. Overall, D-Eye scored better in most of the evaluation items followed by Arclight.
The Chemical Imaging System (CIS) is a small, high-speed long-wave infrared (8 - 12 mum) imaging spectrometer which is currently under development by the United States Army. The fielded system will operate at 360 scan...
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ISBN:
(纸本)0819440760
The Chemical Imaging System (CIS) is a small, high-speed long-wave infrared (8 - 12 mum) imaging spectrometer which is currently under development by the United States Army. The fielded system will operate at 360 scans per second with a large format focal-plane-array. The CIS, which is currently at the exploratory development stage, is scheduled for transition to engineering development in 2005. currently, the CIS uses the TurboFT FTS in conjunction with a 16-pixel direct-wired HgCdTe detector array. The TurboFT spectrometer provides high-speed operation in a small, lightweight package. In parallel to the hardware developments an algorithm and software development effort is underway to address some unique features of the CIS. The TurboFT-based system requires a non-uniform sampling Fourier transform algorithm in order to preserve signal fidelity. Also, the availability of multiple pixels can be exploited in order to improve the interference suppression capabilities of the system by allowing the detection and identification algorithm to adapt its parameters to the changing background. Due to the enormous amount of data generated, the signal processing must proceed at very high rate. High-speed computers operating with a parallel architecture are required to process the data in real time. This paper describes the current CIS "bread box" system. It includes some field measurement results followed by a discussion of the issues and challenges associated with meeting the design goals set for the program.
A multi-band pass filter array was proposed and designed for short wave infrared applications. The central wavelength of the multi-band pass filters are located about 905 nm, 950 nm, 1055 nm and 1550 nm. In the simula...
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ISBN:
(纸本)9781510612082;9781510612075
A multi-band pass filter array was proposed and designed for short wave infrared applications. The central wavelength of the multi-band pass filters are located about 905 nm, 950 nm, 1055 nm and 1550 nm. In the simulation of an optical interference band pass filter, high spectrum performance (high transmittance ratio between the pass band and stop band) relies on (1) the index gap between the selected high/low-index film materials, with a larger gap correlated to higher performance, and (2) sufficient repeated periods of high/low-index thin-film layers. When determining high and low refractive index materials, spectrum performance was improved by increasing repeated periods. Consequently, the total film thickness increases rapidly. In some cases, a thick total film thickness is difficult to process in practice, especially when incorporating photolithography liftoff. Actually the maximal thickness of the photoresist being able to liftoff will bound the total film thickness of the band pass filter. For the application of the short wave infrared with the wavelength range from 900nm to 1700nm, silicone was chosen as a high refractive index material. Different from other dielectric materials used in the visible range, silicone has a higher absorptance in the visible range opposite to higher transmission in the short wave infrared. In other words, designing band pass filters based on silicone as a high refractive index material film could not obtain a better spectrum performance than conventional high index materials like TiO2 or Ta2O5, but also its material cost would reduce about half compared to the total film thickness with the conventional material TiO2. Through the simulation and several experimental trials, the total film thickness below 4 um was practicable and reasonable. The fabrication of the filters was employed a dual electric gun deposition system with ion assisted deposition after the lithography process. Repeating four times of lithography and deposition p
The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for gamma-ray astronomy, covering an energy range from a few tens of GeV to a few hundred TeV. The CTA project is currently in t...
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ISBN:
(纸本)9781628417692
The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for gamma-ray astronomy, covering an energy range from a few tens of GeV to a few hundred TeV. The CTA project is currently in the design and prototyping phase, the start of construction is planned for 2016. The planned sensitivity of CTA improves on current ground based Cherenkov telescope experiments by about an order of magnitude. In the core energy range this sensitivity will be dominated by up to 40 Medium-Sized Telescopes (MSTs). These telescopes, of a modified Davies-Cotton mount type with a reflector diameter of 12 m, are currently being prototyped. A full-size mechanical prototype has been operating in Berlin since 2012. Several types of prototype mirrors have been developed and tested, and are mounted on the telescope. CCD cameras with various lenses are mounted on the prototype for studying deformation of the structure, testing alignment techniques, and telescope pointing using astrometry methods. The report will focus on results of optical and structural measurements, commissioning and testing of the MST prototype in Berlin, as well as the final design.
In this paper, we report on currentdevelopments aimed at improving the focusability of the Texas Petawatt Laser. Two major campaigns have been commissioned that address the issue of focusability. First, we implemente...
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ISBN:
(纸本)9780819484505
In this paper, we report on currentdevelopments aimed at improving the focusability of the Texas Petawatt Laser. Two major campaigns have been commissioned that address the issue of focusability. First, we implemented a closed loop, 32 actuator bi-moprh deformable mirror (DFM) to compensate for aberrations in the optical train and second, a color corrector lens assembly was installed that compensates for chromatic errors accumulated in broadband (>15 nm), large aperture (> 20 cm) laser systems. We will present in detail, pre and post correction results with the DFM and describe challenges faced when one activates a single shot, high energy closed loop system. Secondly, we will provide modeling and experimental results of our color correction system. This is a novel approach to a problem only seen in high energy, broadband, large aperture laser pulses. By using color correction optics we have demonstrated a 6X increase in focal intensity. With the installation of the DFM, the rms wavefront error in the system was reduced from 2.4 waves to. 131 waves, further increasing intensities seen at focus by 1 order of magnitude.
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