Ashton Peters

Learn More
Results from the application of a Digital Image Elasto-Tomography (DIET) system to elasticity distribution estimation in heterogeneous phantoms are presented. Two simple phantoms comprising distinct hard and soft regions were created from silicone, with harmonic surface motion data captured using a steady-state stereo imaging setup. A two-parameter approach(More)
Results from the application of three nonlinear stiffness reconstruction algorithms to two simple cylindrical geometries are presented in this paper. Finite-element simulated harmonic motion data with added noise were initially used to represent a measured surface displacement dataset for each geometry. This motion was used as input to gradient-descent,(More)
The application of a surface motion error based elasticity estimation method to hard and soft silicone phantom data is presented. Steady-state harmonic surface motion was measured at a limited number of measurement sites, and fitted with an ideal damped motion path. A finite element (FE) model was used to simulate phantom motion at a range of modulus and(More)
In June 2003 it was decided that the GSI Beam Diag-nostics (BD) group would act as contractor for the delivery of beam diagnostic devices for the heavy-ion cancer therapy facility HIT in Heidelberg. The contract included the production of the mechanical parts (feed-throughs, detectors etc.) as well as the integration of the 92 diagnos-tics devices of HIT to(More)
Experimental results in the application of a gradient descent to-mographic elasticity reconstruction method to measured soft tissue phantom data are presented. Surface motions at a limited number of measurement sites were used to reconstruct a global stiffness parameter for a homogeneous gelatine phantom. Results corresponded well with expected values and(More)
A10 The mission OPTIS aims at improving tests of the foundations of Special and General Relativity by up to three orders of magnitude. The individual tests concern r the isotropy and r constancy of the speed of light, r the time dilation (or Doppler effect), r the universality of the gravitational redshift with various combinations of high precision clocks.(More)
For the characterization of the 10 mA ion beam delivered by the new High Current Linac at GSI, sophisticated , mainly non-intersepting diagnostic devices were developed. Besides the general setup of a versatile test bench, we discuss in particular bunch shape and emittance measurements. A direct time-of-flight technique with a diamond particle detector is(More)
Three beam diagnostics developments for the current operation of the SIS18 and the high energy beam transport (HEBT) lines are described: a service program for SIS18 diagnostics, a tool for spill structure analysis and the renewed beam position monitor system in the HEBT lines. Since SIS operating started, a lot of measurements for beam characterisation(More)
The first steps of research and design made for the BPM (beam position monitor) system for the FAIR project , with partly use for the SIS-18 upgrade, will be described. It includes the evaluation software parts as well as the hardware part for the direct digitization of the position pickup signals and, in addition, the first design steps for the cryogenic(More)
The present Beam Position Monitor (BPM) electronics lacks a reliable evaluation for bunch-by-bunch measurements and has to be renewed. After the data collection and offline evaluation in 2005, the completed prototype 125MSa/s ADC-board connected to a high performance Xilinx Virtex II Pro FPGA was tested. The hardware is described more detailed in [1].(More)