A pixel detector system for laser-accelerated ion detection

作者：Reinhardt S^*; Draxinger W; Schreiber J; Assmann W

来源：Journal of Instrumentation, 2013, 8(03): P03008.

DOI：10.1088/1748-0221/8/03/P03008

• Solid state detectors
• Instrumentation for particle accelerators and storage rings - low energy (linear accelerators, cyclotrons, electrostatic accelerators)
• Instrumentation for heavy-ion accelerators

Laser ion acceleration is an unique acceleration process that creates ultra-short ion pulses of high intensity (> 10(7) ions/cm(2)/ns), which makes online detection an ambitious task. Non-electronic detectors such as radio-chromic films (RCF), imaging plates (IP) or nuclear track detectors (e. g. CR39) are broadly used at present. Only offline information on ion pulse intensity and position are available by these detectors, as minutes to hours of processing time are required after their exposure. With increasing pulse repetition rate of the laser system, there is a growing need for detection of laser accelerated ions in real-time.
Therefore, we have investigated a commercial pixel detector system for online detection of laser-accelerated proton pulses. The CMOS imager RadEye1 was chosen, which is based on a photodiode array, 512x1024 pixels with 48 mu m pixel pitch, thus offering a large sensitive area of approximately 25x50 mm(2). First detection tests were accomplished at the conventional electrostatic 14 MV Tandem accelerator in Munich as well as Atlas laser accelerator. Detector response measurements at the conventional accelerator have been accomplished in a proton beam in dc (15 MeV) and pulsed (20 MeV) irradiation mode, the latter providing comparable particle flux as under laser acceleration conditions. Radiation hardness of the device was studied using protons (20 MeV) and C-ions (77 MeV), additionally. The detector system shows a linear response up to a maximum pulse flux of about 10(7) protons/cm(2)/ns. Single particle detection is possible in a low flux beam (10(4) protons/cm(2)/s) for all investigated energies. The radiation hardness has shown to give reasonable lifetime for an application at the laser accelerator. The results from the irradiation at a conventional accelerator are confirmed by a cross-calibration with CR39 in a laser-accelerated proton beam at the MPQ Atlas Laser in Garching, showing no problems of detector operation in presence of electro-magnetic pulse (EMP). The calibrated detector system was finally used for online detection of laser-accelerated proton and carbon ions at the Astra-Gemini laser.

• 出版日期2013-3