Radiation hardness studies of AMS HV-CMOS 350 nm prototype chip HVStripV1
Journal of Instrumentation IOP Publishing 12:02 (2017) P02010
Abstract:
CMOS active pixel sensors are being investigated for their potential use in the ATLAS inner tracker upgrade at the HL-LHC. The new inner tracker will have to handle a significant increase in luminosity while maintaining a sufficient signal-to-noise ratio and pulse shaping times. This paper focuses on the prototype chip "HVStripV1" (manufactured in the AMS HV-CMOS 350nm process) characterization before and after irradiation up to fluence levels expected for the strip region in the HL-LHC environment. The results indicate an increase of depletion region after irradiation for the same bias voltage by a factor of ≈2.4 and ≈2.8 for two active pixels on the test chip. There was also a notable increase in noise levels from 85 e− to 386 e− and from 75 e− to 277 e− for the corresponding pixels.'GP2' - An energy resolved neutron imaging detector using a Gd coated CMOS sensor
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015 IEEE (2016)
Abstract:
This paper documents the R&D; undertaken jointly by the ISIS Neutron Detector Group and the Oxford University PImMS collaboration. The aim of this project was to develop a high resolution, energy resolved, neutron imaging detector named GP2. This conference record introduces the GP2 detector and lists its key physical properties; however the emphasis here will be on the earlier proof-of-principle work performed with both gadolinium thin films and thick rolled sheets with the prototype PImMS1 sensor and the larger PImMS2 sensor.Investigation of HV/HR-CMOS technology for the ATLAS Phase-II Strip Tracker Upgrade
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment Elsevier 831 (2016) 189-196
Study of built-in amplifier performance on HV-CMOS sensor for the ATLAS phase-II strip tracker upgrade
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Elsevier 831 (2016) 156-160
Abstract:
This paper focuses on the performance of analog readout electronics (built-in amplifier) integrated on the high-voltage (HV) CMOS silicon sensor chip, as well as its radiation hardness. Since the total collected charge from minimum ionizing particle (MIP) for the CMOS sensor is 10 times lower than for a conventional planar sensor, it is crucial to integrate a low noise built-in amplifier on the sensor chip to improve the signal to noise ratio of the system. As part of the investigation for the ATLAS strip detector upgrade, a test chip that comprises several pixel arrays with different geometries, as well as standalone built-in amplifiers and built-in amplifiers in pixel arrays has been fabricated in a 0.35 μm high-voltage CMOS process. Measurements of the gain and the noise of both the standalone amplifiers and built-in amplifiers in pixel arrays were performed before and after gamma radiation of up to 60 Mrad. Of special interest is the variation of the noise as a function of the sensor capacitance. We optimized the configuration of the amplifier for a fast rise time to adapt to the LHC bunch crossing period of 25 ns, and measured the timing characteristics including jitter. Our results indicate an adequate amplifier performance for monolithic structures used in HV-CMOS technology. The results have been incorporated in the next submission of a large-structure chip.Charge collection studies in irradiated HV-CMOS particle detectors
Journal of Instrumentation IOP Publishing 11:4 (2016) P04007