GLI2 Is a Regulator of beta-Catenin and Is Associated with Loss of E-Cadherin, Cell Invasiveness, and Long-Term Epidermal Regeneration

Research Advisory Board of the Barts and the London Charity (Grant DERG1D8R

Ageing and proton irradiation damage of a low voltage EMCCD in a CMOS process

Electron Multiplying Charge Coupled Devices (EMCCDs) have revolutionised low light level imaging, providing highly sensitive detection capabilities. Implementing Electron Multiplication (EM) in Charge Coupled Devices (CCDs) can increase the Signal to Noise Ratio (SNR) and lead to further developments in low light level applications such as improvements in image contrast and single photon imaging. Demand has grown for EMCCD devices with properties traditionally restricted to Complementary Metal-Oxide-Semiconductor (CMOS) image sensors, such as lower power consumption and higher radiation tolerance. However, EMCCDs are known to experience an ageing effect, such that the gain gradually decreases with time. This paper presents results detailing EM ageing in an Electron Multiplying Complementary Metal-Oxide-Semiconductor (EMCMOS) device and its effect on several device characteristics such as Charge Transfer Inefficiency (CTI) and thermal dark signal. When operated at room temperature an average decrease in gain of over 20% after an operational period of 175 hours was detected. With many image sensors deployed in harsh radiation environments, the radiation hardness of the device following proton irradiation was also tested. This paper presents the results of a proton irradiation completed at the Paul Scherrer Institut (PSI) at a 10 MeV equivalent fluence of 4.15 × 1010 protons/cm2. The pre-irradiation characterisation, irradiation methodology and post-irradiation results are detailed, demonstrating an increase in dark current and a decrease in its activation energy. Finally, this paper presents a comparison of the damage caused by EM gain ageing and proton irradiation

Development of light-field motion tracking technology for use in laboratory studies of planet formation

Modelling of planet formation requires empirical data on the collisions involved in the earliest stages of the process. Laboratory-based studies are required to gain this data by colliding dusty, icy particles in conditions analogous to those found in protoplanetary disks. Having technology to capture experimental footage and extract the three-dimensional motions of ensembles of particles is crucial to generating accurate collisional data within a practical timeframe. The cost of microgravity-based experiments drives a need to minimize the form-factor of such an imaging system leading this work to use light-field techniques to provide the depth element of tracking from a single camera. This work focused on the development of software to be used to perform light-field based, three-dimensional tracking and its application to real-time analysis of mm-scale particle collisions

Novel method for identifying the cause of inherent ageing in Electron Multiplying Charge Coupled Devices

The charge multiplication process used in the Electron Multiplying CCD (EMCCD) is subject to an ageing effect in which the gain achieved at particular avalanche potentials, gradually decreases during operation. To utilise these devices for both space and terrestrial applications where recalibration of the gain is not feasible, a comprehensive understanding of the ageing process is required. A custom automated test equipment (ATE) has been produced and used to develop the techniques required for investigating the ageing process alongside the verification of simulation work on the subject. Simulation work carried out by e2v technologies has suggested hole build-up at the Si/Si02 interface below one of the transfer gates. This build up of holes has now been linked with a reduction in avalanche potential in the device. A novel experimental technique has therefore been developed to determine the actual potentials within the device and thereby determine the validity of this prediction. The initial results tend to support simulation as an increase in the potential beneath one of the phases is observed