Comparing the Economic Impact of an Export Shock in Two Modeling Frameworks

Because of more restrictive assumptions on regional input-output (IO) models compared to computable general equilibrium (CGE) models, the literature agrees IO results are intuitively consistent with long run equilibrium but otherwise overestimated. We compare the results of IO and CGE models from an exogenous export shock under various labor market constraints and capital closures. Consistent with the literature, we find the IO model's results do not match those of the CGE models. But contrary to conventional wisdom, the positive secondary impacts are larger with the CGE models than with the IO model. Furthermore, we find the closest match between direct effects is when the CGE model has short run restrictions. Our finding means that the common view of CGE model results being both lower in estimate and more accurate in the short run than IO models does not universally hold. Thus researchers’ choice of models and interpretation of results need to be more nuanced and cautious than previously thought.input-output, computable general equilibrium, economic impacts, exports

C3TM: CEI CCD charge transfer model for radiation damage analysis and testing

Radiation induced defects in the silicon lattice of Charge Couple Devices (CCDs) are able to trap electrons during read out and thus create a smearing effect that is detrimental to the scientific data. To further our understanding of the positions and properties of individual radiation-induced traps and how they affect space- borne CCD performance, we have created the Centre for Electronic Imaging (CEI) CCD Charge Transfer Model (C3TM). This model simulates the physical processes taking place when transferring signal through a radiation damaged CCD. C3TM is a Monte Carlo model based on Shockley-Read-Hall theory, and it mimics the physical properties in the CCD as closely as possible. It runs on a sub-electrode level taking device specific charge density simulations made with professional TCAD software as direct input. Each trap can be specified with 3D positional information, emission time constant and other physical properties. The model is therefore also able to simulate multi-level clocking and other complex clocking schemes, such as trap pumping

Postirradiation behavior of p-channel charge-coupled devices irradiated at 153 K

The displacement damage hardness that can be achieved using p-channel charge-coupled devices (CCD) was originally demonstrated in 1997, and since then a number of other studies have demonstrated an improved tolerance to radiation-induced CTI when compared to n-channel CCDs. A number of recent studies have also shown that the temperature history of the device after the irradiation impacts the performance of the detector, linked to the mobility of defects at different temperatures. This study describes the initial results from an e2v technologies p-channel CCD204 irradiated at 153 K with a 10 MeV equivalent proton fluences of 1.24×109 and 1.24×1011 protons cm-2. The dark current, cosmetic quality and the number of defects identified using trap pumping immediately were monitored after the irradiation for a period of 150 hours with the device held at 153 K and then after different periods of time at room temperature. The device also exhibited a flatband voltage shift of around 30 mV / krad, determined by the reduction in full well capacity

Hex Player—a virtual musical controller

In this paper, we describe a playable musical interface for tablets and multi-touch tables. The interface is a generalized keyboard, inspired by the Thummer, and consists of an array of virtual buttons. On a generalized keyboard, any given interval always has the same shape (and therefore fingering); furthermore, the fingering is consistent over a broad range of tunings. Compared to a physical generalized keyboard, a virtual version has some advantages—notably, that the spatial location of the buttons can be transformed by shears and rotations, and their colouring can be changed to reflect their musical function in different scales. We exploit these flexibilities to facilitate the playing not just of conventional Western scales but also a wide variety of microtonal generalized diatonic scales known as moment of symmetry, or well-formed, scales. A user can choose such a scale, and the buttons are automatically arranged so their spatial height corresponds to their pitch, and buttons an octave apart are always vertically above each other. Furthermore, the most numerous scale steps run along rows, while buttons within the scale are light-coloured, and those outside are dark or removed. These features can aid beginners; for example, the chosen scale might be the diatonic, in which case the piano’s familiar white and black colouring of the seven diatonic and five chromatic notes is used, but only one scale fingering need ever be learned (unlike a piano where every key needs a different fingering). Alternatively, it can assist advanced composers and musicians seeking to explore the universe of unfamiliar microtonal scales

Imaging and spectroscopy using a scintillator-coupled EMCCD

The CCD97 is a low light level (L3) device from e2v technologies range of electron multiplying CCDs (EMCCDs). The device uses e2v's patented extended gain register and through the use of appropriately designed electrodes can be used to maximise the signal whilst keeping the impact of the noise to a minimum. The nature of this device makes it ideal for use with a scintillator in order to see individual flashes of light from single X-ray photons. Through the examination of individual X-ray events, it is possible to analyse each interaction in the scintillator to determine the sub-pixel position of the interaction. Using the modelling capabilities of the Geant4 toolkit it is possible to simulate X-ray events and thus examine interactions with known energy and point of interaction. Through bringing together the experimental and simulated results, the spectral capabilities of such a device are discussed

Evolution and impact of defects in a p-channel CCD after cryogenic proton-irradiation

P-channel CCDs have been shown to display improved tolerance to radiation-induced charge transfer inefficiency (CTI) when compared to n-channel CCDs. However, the defect distribution formed during irradiation is expected to be temperature dependent due to the differences in lattice energy caused by a temperature change. This has been tested through defect analysis of two p-channel e2v CCD204 devices, one irradiated at room temperature and one at a cryogenic temperature (153K). Analysis is performed using the method of single trap pumping. The dominant charge trapping defects at these conditions have been identified as the donor level of the silicon divacancy and the carbon interstitial defect. The defect parameters are analysed both immediately post irradiation and following several subsequent room-temperature anneal phases up until a cumulative anneal time of approximately 10 months. We have also simulated charge transfer in an irradiated CCD pixel using the defect distribution from both the room-temperature and cryogenic case, to study how the changes affect imaging performance. The results demonstrate the importance of cryogenic irradiation and annealing studies, with large variations seen in the defect distribution when compared to a device irradiated at room-temperature, which is the current standard procedure for radiation-tolerance testing

The relationship between pumped traps and signal loss in buried channel CCDs

Pocket-pumping is an established technique for identifying the locations of charge trapping sites within the transport channels of CCDs. Various parameters of the pumping process can be manipulated to increase the efficiency, or allow characterisation of the trap sites effective during nominal operating modes. A CCD273 was irradiated in a triangular region by protons to a 10 MeV equivalent fluence of 1.2E9 p cm2, ensuring a suitably low trap density for ease of automated trap recognition. X-rays of 5,898 eV were incident on the CCD above the region irradiated with the triangle, such that events could be analysed having passed through an increasing length of irradiated silicon and hence number of trapping sites. Here we present the relationship between the number of traps identified by pocket pumping within the parallel transport channels of a CCD273 and the amount of signal that is deferred by the trapping process during readout

Importance of charge capture in interphase regions during readout of charge-coupled devices

The current understanding of charge transfer dynamics in charge-coupled devices (CCDs) is that charge is moved so quickly from one phase to the next in a clocking sequence and with a density so low that trapping of charge in the interphase regions is negligible. However, simulation capabilities developed at the Centre for Electronic Imaging, which includes direct input of electron density simulations, have made it possible to investigate this assumption further. As part of the radiation testing campaign of the Euclid CCD273 devices, data have been obtained using the trap pumping method, a method that can be used to identify and characterize single defects within CCDs. Combining these data with simulations, we find that trapping during the transfer of charge among phases is indeed necessary to explain the results of the data analysis. This result could influence not only trap pumping theory and how trap pumping should be performed but also how a radiation-damaged CCD is readout in the most optimal way