Application of the Medipix2 technology to space radiation dosimetry and hadron therapy beam monitoring

AbstraktAbstract

The Medipix2 Collaboration, based at CERN, has developed the TimePix version of the Medipix pixel readout chip, which has the ability to provide either an ADC or TDC capability separately in each of its 256 x 256 pixels. When coupled to a Si detector layer, the device is an excellent candidate for application as an active dosimeter for use in Space Radiation Environments. In order to facilitate such a development, data have been taken with Heavy Ions at the HIMAC facility in Chiba, Japan. In particular, the problem of determining the resolution of such a detector system with respect to heavy ions of differing charges and energies, but with similar dE/dx values has been explored for several ions. The ultimate problem is to parse the information in the pixel "footprint" images from the drift of the charge-cloud produced in the detector layer. In addition, with the use of convertor materials, the detector can be used as a neutron detector, and it has been used both as a charged particle and neutron detector to evaluate the detailed properties of the radiation fields produced by hadron therapy beams. The first space flight of a Medipix-based detector is currently planned for the first quarter of 2012 onboard the UK TechDemoSat-1 satellite as part of the LUCID project. The instrument to be flown is currently planned to have 5 TimePix versions of the Medipix2 detector deployed on 5 of the 6 faces of a cube with similar to 3 cm on each side and enclosed by a 0.7 mm thick Al cylindrical cover.

The Medipix2 Collaboration, based at CERN, has developed the TimePix version of the Medipix pixel readout chip, which has the ability to provide either an ADC or TDC capability separately in each of its 256 x 256 pixels. When coupled to a Si detector layer, the device is an excellent candidate for application as an active dosimeter for use in Space Radiation Environments. In order to facilitate such a development, data have been taken with Heavy Ions at the HIMAC facility in Chiba, Japan. In particular, the problem of determining the resolution of such a detector system with respect to heavy ions of differing charges and energies, but with similar dE/dx values has been explored for several ions. The ultimate problem is to parse the information in the pixel "footprint" images from the drift of the charge-cloud produced in the detector layer. In addition, with the use of convertor materials, the detector can be used as a neutron detector, and it has been used both as a charged particle and neutron detector to evaluate the detailed properties of the radiation fields produced by hadron therapy beams. The first space flight of a Medipix-based detector is currently planned for the first quarter of 2012 onboard the UK TechDemoSat-1 satellite as part of the LUCID project. The instrument to be flown is currently planned to have 5 TimePix versions of the Medipix2 detector deployed on 5 of the 6 faces of a cube with similar to 3 cm on each side and enclosed by a 0.7 mm thick Al cylindrical cover.