Characterization of a compact, high resolution readout system for micro-pattern gaseous detectors

Abstract: A Linear e+e- collider, either ILC or CLIC will be the next platform for high energy physics study to complement the LHC. Results discovered by LHC may need precision measurements before we can get full understanding of the physics. International collaborations are in the process to prepare both for the accelerator and for the experimental setup. Time projection chambers as the main central tracking devices are used in various experiments. It provides good resolution for 3D track reconstruction. However, the large readout granularity needed to meet the resolution goals imposes stringent requirements on the readout electronics and the mechanical construction. For the electronics, the requirements on miniaturization, the data volume and transfer bandwidth, temperature stability, power consumption and radiation hardness, high density of integration have to be driven to the technical limits and the detector development towards this is going on for the linear collider experiment. To meet these needs, S-ALTRO16 chip was recently designed and the first prototypes are available for characterization. It integrates the analog amplification part with the digitization and signal processing parts into a single silicon chip. In particular, maintaining the resolution while integrating a highly sensitive analog front end with a digital part is an expected difficulty. In order to evaluate the possible effect on the resolution by this integration step we have performed the same (as far as possible) characterization of the existing readout system, where the analog and digital functions were implemented in separate chips (PCA16+ALTRO). In addition to performing the tests, the methodology for the test has to be developed. In this thesis, the system noise issues are studied and measurements were done with the system. To better understand the system behavior, all the main functional components of the front end electronics were studied. To calibrate the system, it was studied how to best quantify the pulse amplitude when the sampling rate of the ADC is finite and the pulse is random in phase to the sampling clock. Since the amplifier chip is programmable, in terms of input polarity, peaking time and conversion gain, this readout system can be used not only for a large variety of gaseous ionization chambers but also for a wider family of radiation detectors and other signal sources. The main conclusion of the thesis is that the noise performance after the integration step, represented by the S-ALTRO16, is quite comparable to the performance before integration. The performance is close to the theoretical limit and we conclude that the integration has not resulted in any noticeable deterioration of the noise of the readout system.