1,394 research outputs found
Proton irradiation of e2v technologies L3Vision devices
This paper describes the proton irradiation and subsequent analysis of 8 e2v technologies CCD65 L3Vision devices with the intention of assessing the suitability of L3Vision technology to applications in space. In particular the use of L3Vision charge coupled devices (CCDs) on the Radial Velocity Spectrometer (RVS) instrument of the planned European Space Agency GAIA mission is discussed. The operational properties of the devices were characterised before irradiation with protons to a 10 MeV equivalent fluence of 2.5 × 109 protons cm-2. The devices were then characterised again before undergoing a second proton irradiation which increased the total 10 MeV equivalent proton fluence received by each device to 2.1 × 1010 protons cm-2. All 8 devices functioned as expected after each irradiation, with no catastrophic failures occurring even after the second irradiation which increased the total proton fluence to approximately 10 times the expected 6 year RVS fluence
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Random telegraph signals in charge coupled devices
An investigation of fluctuating pixels resulting from proton irradiation of an E2V Technologies CCD47-20 device is presented. The device structure,experimental set up and irradiation methodology are described, followed by a detailed analysis of radiation induced random telegraph signals,RTS. The characteristics of the observed flickering pixels are discussed in detail and the proposed models explaining the mechanism behind the phenomena are viewed in light of the collected data
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The effect of protons on E2V technologies L3Vision CCDs
The effect of different 10 MeV equivalent proton fluences on the performance of E2V Technologies (formerly Marconi applied technologies, formerly EEV) L3Vision Charge Coupled Devices (CCDs) was investigated. The first experimental radiation damage results of the L3Vision device are presented, with emphasis given to the analysis of damage to the gain register of the device. Changes in dark current and generation of bright pixels in the CCD image, store, readout register and gain register as a result of proton irradiation are reported and viewed in light of the potential use of the device in space-based applications
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Proton irradiation of EMCCDs
This paper describes the irradiation of 95 electron multiplication charge coupled devices (EMCCDs) at the Paul Scherrer Institut (PSI) in Switzerland, to investigate the effects of proton irradiation on the operational characteristics of CCDs featuring electron multiplication technology for space use. This work was carried out in support of the CCD development for the radial velocity spectrometer (RVS) instrument of the European Space Agency's cornerstone Gaia mission. Previous proton irradiations of EMCCDs, have shown the technology to be radiation hard to /spl sim/10/spl times/ the required six-year Gaia lifetime proton fluence, with no device failures or unexpected operational changes. The purpose of the study described in this paper was to further investigate the statistical probability of device failure as a result of radiation damage, the large number of devices and high proton fluence used, making the study equivalent to testing /spl sim/50 complete RVS CCD focal planes to the expected end of life proton dose. An outline of the earlier EMCCD proton irradiations is given, followed by a detailed description of the proton irradiation and characterization of the 95 devices used in this latest study
Proton induced leakage current in CCDs
The effect of different proton fluences on the performance of two E2V Technologies CCD47-20 devices was investigated with particular emphasis given to the analysis of 'random telegraph signal' (RTS) generation, bright pixel generation and induced changes in base dark current level. The results show that bright pixel frequency increases as the mean energy of the proton beam is increased, and that the base dark current level after irradiation scales with the level of ionization damage. For the RTS study, 500 pixels on one device were monitored over a twelve hour period. This data set revealed a number of distinct types of pixel change level fluctuation and a system of classification has been devised. Previously published RTS data is discussed and reviewed in light of the new data
Application of electron multiplying CCD technology in space instrumentation
Electron multiplying CCD (EMCCD) technology has found important initial applications in low light surveillance and photon starved scientific instrumentation. This paper discusses the attributes of the EMCCD which make it useful for certain space instruments, particularly those which are photon starved, and explores likely risks from the radiation expected in such instruments
EMCCDs for space applications
This paper describes a qualification programme for Electron-Multiplication Charge Coupled Devices (EMCCDs) for use in space applications. While the presented results are generally applicable, the programme was carried out in the context of CCD development for the Radial Velocity Spectrometer (RVS) instrument on the European Space Agency's cornerstone Gaia mission. We discuss the issues of device radiation tolerance, charge transfer efficiency at low signal levels and life time effects on the electron-multiplication gain. The development of EMCCD technology to allow operation at longer wavelengths using high resistivity silicon, and the cryogenic characterisation of EMCCDs are also described
Development and Testing of a 2-D Transfer CCD
This paper describes the development, operation,
and characterization of charge-coupled devices (CCDs) that feature an electrode structure that allows the transfer of charge both horizontally and vertically through the image area. Such devices have been termed two-dimensional (2-D) transfer CCDs (2DT CCDs), as opposed to the conventional devices, which might be called one-dimensional transfer CCDs, but in other respects are the same as conventional CCD devices. Batches of two different 2DT CCD test devices, featuring different electrode structures but with identical clocking operation in each case, were produced and
tested. The methodology of 2-D charge transfer in each of the device types is described, followed by a presentation of test results from the new CCDs. The ability of both 2DT CCD transfer electrode schemes to successfully transfer charge in both horizontal and vertical directions in the image section of the devices has been proven, opening up potential new applications for 2DT CCD use
Low noise charge injection in the CCD22
The inclusion of a charge injection structure on a charge coupled device (CCD) allows for the mitigation of charge transfer loss which can be caused by radiation induced charge trapping defects. Any traps present in the pixels of the CCD are filled by the injected charge as it is swept through the device and consequently, the charge transfer efficiency is improved in subsequently acquired images. To date, a number of different types of CCD have been manufactured featuring a variety of charge injection techniques. The e2v Technologies CCD22, used in the EPIC MOS focal plane instruments of XMM-Newton, is one such device and is the subject of this paper. A detailed understanding of charge injection operation and the use of charge injection to mitigate charge transfer losses resulting from radiation damage to CCDs will benefit a number of space projects planned for the future, including the ESA GAIA and X-ray Evolving Universe Spectrometry (XEUS) missions.The charge injection structure and mode of operation of the CCD22 are presented, followed by a detailed analysis of the uniformity and repeatability of the charge injection amplitude across the columns of the device. The effects of proton irradiation on the charge injection characteristics are also presented, in particular the effect of radiation induced bright pixels on the injected charge level
Untersuchungen zur Herstellung von agglomerierten Anionenaustauschern auf Styrol- und Methacrylat-Basis
Trägerpartikel wurden durch die Funktionalisierung hochquervernetzter PS-DVB-Harze mit konzentrierter Schwefelsäure erhalten. Die Sulfonierungsreaktion erwies sich als gut reproduzierbar.
Die Emulsionspolymerisation von Latexpartikeln des Styrol-Typs wurde anhand des VBC-DVB-Monomersystems untersucht, in dem kritische Verfahrensparameter systematisch variiert wurden. Zur Charakterisierung der Produkte fanden die Photonenkorrelationsspektroskopie sowie die Rasterelektronenmikroskopie Anwendung. Nach der Übertragung des Polymerisationsverfahrens gelang es, Latexpartikel aus GMA-EGDMA, THFMA-EGDMA und HPMA-Monomersystemen zu synthetisieren und als funktionelle Latexpartikel in agglomerierten Anionenaustauschern einzusetzen.
Als Ursache für Reproduzierbarkeitsprobleme von VBC-DVB-Latexsäulen wurde die Bildung von Agglomeraten während der Funktionalisierung des Latex identifiziert. Dies war auch der Grund für den hohen Staudruck von Methacrylat-Säulen, der in einem Langzeittest zu frühzeitigen Trennleistungsverlusten führte.
Die Charakterisierung der hergestellten Trennsäulen-Typen zeigte, dass der alleinige Ersatz des Styrol-ähnlichen VBC-DVB-Latex durch Methacrylat-Latices mit einer signifikanten Verbesserung der Peaksymmetrie für polarisierbare Anionen wie Bromid und Nitrat einhergeht. Des Weiteren wurde mit THFMA-EGDMA-Latexsäulen eine Auflösung des Fluorids vom Injektionspeak erreicht und nahezu identische Trennleistungen für alle acht untersuchten anorganischen Anionen erhalten. Die chemische Struktur der funktionellen Gruppe auf dem Latex hatte Auswirkungen auf die Selektivität für leicht polarisierbare und mehrfach geladenen Anionen, deren Ursache unterschiedliche Ladungsdichten und Hydratisierungen darstellen. An VBC-DVB-Trennsäulen wurde darüber hinaus eine Zunahme des Peaktailings mit der Polarität des quartären Ammonium-Ions beobachtet
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