A Radiation hard bandgap reference circuit in a standard 0.13um CMOS Technology

With ongoing CMOS evolution, the gate-oxide thickness steadily decreases, resulting in an increased radiation tolerance of MOS transistors. Combined with special layout techniques, this yields circuits with a high inherent robustness against X-rays and other ionizing radiation. In bandgap voltage references, the dominant radiation-susceptibility is then no longer associated with the MOS transistors, but is dominated by the diodes. This paper gives an analysis of radiation effects in both MOSdevices and diodes and presents a solution to realize a radiation-hard voltage reference circuit in a standard CMOS technology. A demonstrator circuit was implemented in a standard 0.13 m CMOS technology. Measurements show correct operation with supply voltages in the range from 1.4 V down to 0.85 V, a reference voltage of 405 mV 7.5 mV ( = 6mVchip-to-chip statistical spread), and a reference voltage shift of only 1.5 mV (around 0.8%) under irradiation up to 44 Mrad (Si)

Performance of a GridPix detector based on the Timepix3 chip

A GridPix readout for a TPC based on the Timepix3 chip is developed for future applications at a linear collider. The GridPix detector consists of a gaseous drift volume read out by a single Timepix3 chip with an integrated amplification grid. Its performance is studied in a test beam with 2.5 GeV electrons. The GridPix detector detects single ionization electrons with high efficiency. The Timepix3 chip allowed for high sample rates and time walk corrections. Diffusion is found to be the dominating error on the track position measurement both in the pixel plane and in the drift direction, and systematic distortions in the pixel plane are below 10 $\mu$m. Using a truncated sum, an energy loss (dE/dx) resolution of 4.1% is found for an effective track length of 1 m.Comment: To be published in Nuclear Instruments and Methods in Physics Research Section

The detection of single electrons by means of a Micromegas-covered MediPix2 pixel CMOS readout circuit

A small drift chamber was read out by means of a MediPix2 readout chip as direct anode. A Micromegas foil was placed 50 $\mu$m above the chip, and electron multiplication occurred in the gap. With a He/Isobutane 80/20 mixture, gas multiplication factors up to tens of thousands were achieved, resulting in an efficiency for detecting single electrons of better than 90% . We recorded many frames containing 2D images with tracks from cosmic muons. Along these tracks, electron clusters were observed, as well as delta-rays.Comment: 15 pages, 9 included postscript figures, 5 separate jpeg figures, submitted to Nucl. Instr. and Meth. A. A complete postscript version with high resolution figures 1, 3, 11, 12 and 14 can be found at http://www.nikhef.nl/~i06/RandD/final/letter4.p