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

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

Antecedents and postcedents of satisfaction in business relationships in Canada

This paper reports the findings of an investigation of whether trust and commitment influence satisfaction, and whether satisfaction then influences specific investments, opportunism, and formalisation. Using data collected in a survey of Canadian managers and executives, a model derived from marketing theory and previous empirical research was tested. The model includes both relationship marketing concepts and transaction cost theory concepts, an approach rarely encountered in existing studies. Satisfaction in an exchange relationship is formed by keeping promises in an iterative process, and serves as a safeguard against possible future risks (e.g., opportunism). Finally, we discuss the limitations of the study

Inter-relationships among focal dimensions in relationship quality: a quantitative and exploratory approach

It is generally agreed that the relationship quality (RELQUAL) in business exchange situations is important. However, there does not appear to be a consensus on the conceptualisation and measurement of the many dimensions of this construct. This may be due to the difficulty in measuring many dimensions in one empirical study. This raises a concern regarding the understanding of the interaction among the various dimensions. Using data gathered in a survey of Canadian managers and executives the present study investigates how focal dimensions pertaining to RELQUAL inter-relate. A model consisting of the following ten dimensions derived from RELQUAL literature was tested: continuity, satisfaction, trust, commitment, opportunism, cooperation, coordination, formalisation, dependence, specific assets. All recommended guidelines for convergent, discriminant and nomological validity, as well as construct reliability, were met

Properties of quality constructs in Canadian business relationships

This paper investigates whether satisfaction, in B2B relationships, is a mediating construct between the antecedents, trust and commitment, and subsequent outcomes. Using data from a survey of Canadian managers and executives, the study tested a structural equation model, the trust, commitment, satisfaction (TCS) model, where the antecedent constructs, trust and commitment, are mediated by the satisfaction construct, which in turn influences coordination, cooperation and continuity or ‘consequence’ constructs. The tested model indicated an acceptable fit, validity and reliability. The analysis in the present study reinforces the argument that satisfaction plays a mediating role in creating enduring relationships in business contexts

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

Developments in Business Gaming A Review of the Past 40 Years

This article examines developments in business simulation gaming during the past 40 years. Covered in this article are a brief history of business games, the changing technology employed in the development and use of business games, changes in why business games are adopted and used, changes in how business games are administered, and the current state of business gaming. Readers interested in developments in other areas of simulation gaming (urban planning, social studies, ecology, economics, geography, health, etc.) are encouraged to look at other articles appearing during the 40th anniversary year of Simulation & Gaming and at the many fine articles that appeared in the silver anniversary issue of Simulation & Gaming (December 1995)

The impact of low energy proton damage on the operational characteristics of EPIC-MOS CCDs

The University of Tübingen 3.5 MeV Van de Graaf accelerator facility was used to investigate the effect of low energy protons on the performance of the European Photon Imaging Camera (EPIC), metal–oxide semiconductor (MOS), charge coupled devices (CCDs). Two CCDs were irradiated in different parts of their detecting areas using different proton spectra and dose rates. Iron-55 was the calibration source in all cases and was used to measure any increases in charge transfer inefficiency (CTI) and spectral resolution of the CCDs. Additional changes in the CCD bright pixel table and changes in the low X-ray energy response of the device were examined. The Monte Carlo code Stopping Range of Ions in Matter (SRIM) was used to model the effect of a 10 MeV equivalent fluence of protons interacting with the CCD. Since the non-ionising energy loss (NIEL) function could not be applied effectively at such low proton energies. From the 10 MeV values, the expected CTI degradation could be calculated and then compared to the measured CTI changes

MOS CCDs for the wide field imager on the XEUS spacecraft

In recent years the XEUS mission concept has evolved and has been the subject of several industrial studies. The mission concept has now matured to the point that it could be proposed for a Phase A study and subsequent flight programme. The key feature of XEUS will be its X-ray optic with collecting area ~30-100x that of XMM. The mission is envisaged at an orbit around the L2 point in space, and is formed from two spacecraft; one for the mirrors, and the other for the focal plane detectors. With a focal length of 50m, the plate scale of the optic is 6.5x that of XMM, which using existing focal plane technology will reduce the effective field of view to a few arc minutes. Cryogenic instrumentation, with detector sizes of a few mm can only be used for narrow field studies of target objects, and a wide field instrument is under consideration using a DEPFET pixel array to image out to a diameter of 5 arcminutes, requiring an array of dimension 70mm. It is envisaged to extend this field of view possibly out to 15 arcminutes through the use of an outer detection ring comprised of MOS CCD