Heavy Ion Response of the TimePix Version of the Medipix2 Technology In Preparation For Use In Space Radiation Dosimetry Applications (11H248)

The CERN-based Medipix2 Collaboration has produced a pixel-based detector called Timepix that includes a 14-bit ADC capability embedded within the footprint of each pixel. This HIMAC project has been an essential part of a larger effort to develop versions of this technology for use in the field of space radiation monitoring and dosimetry. Because of the nature of the space radiation and the relative biological effectiveness of the heavy ions present in it, it is necessary for us to obtain calibration data to enable us to develop the highest precision analysis tools, and to validate the Monte Carlo simulations of the detector in the space radiation environment. We are also required by NASA to have exposed our devices in radiation fields similar to those that will be encountered in space. Six of these Medipix-based devices, all of which were individually calibrated during the HIMAC running reported here have been operated successfully on the International Space Station for more than a year as part of an internal NASA Station Detailed Test Objective. The next generation of this device from the Medipix3 Collaboration, whose properties in part have been heavily influenced by the analysis of the data taken at HIMAC, has been fabricated and is being tested at CERN. In addition, a redesign of the current very successful Medipix2 Timepix device is planned, also driven in part by results obtained during the past running at HIMAC. We have been approved to continue our program at HIMAC over the coming 3-year period to enable us to characterize these improved Medipix2 Timepix devices and the next generation detectors from the Medipix3 Collaboration, along with evaluating their associated flight hardware and software.