GasDet - Development of novel gaseous detectors

The International Linear Collider (ILC) is an accelerator project under discussion in Japan, where electrons and positrons will be accelerated to a center-of-mass energy between 250 GeV and 1 TeV in order to perform precision measurements of Z/W bosons, top quarks, and Higgs bosons. Our group is involved in one of the experiments and contributes to the development of a central tracking chamber. This detector, a time projection chamber (TPC), is an ideal tracking chamber due to its high efficiency, excellent energy resolution, and low material budget. Its properties can be further enhanced by using GridPix detectors for the signal readout.

Due to their lack of electric charge, neutrons have some complementary properties to other constituents of matter such as electrons or protons. They can penetrate our matter much more easily and help to visualize the interior of objects. Therefore, they are used in scattering experiments or in imaging to study objects that cannot be penetrated by X-rays or gamma photons or do not provide sufficient contrast. However, detecting neutrons and determining their location is much more difficult than for other particles and requires special atoms for capture and subsequently decay of the neutrons. We are developing three different detectors for accurate measurement of the conversion locations.

Polarization is another property of light besides color and intensity and can be used to gain knowledge either about the physical processes in the light source or the physical processes during the scattering process at an object. While polarization in the optical range is used for some industrial applications, polarization of X-ray photons has been technically almost inaccessible and therefore has few applications even in research. Based on the GridPix technology, we are therefore developing a polarization detector for X-rays, which can then be used in material science as well as in astrophysical experiments on satellites.

The demands on the detectors will continue to increase in future experiments. Therefore, a continuous development of the detectors is necessary in order to cope with the future challenges. For example, the requirements for rate capability and improved time resolution will play an important role in future experiments. We are therefore trying to understand limiting properties of our current detectors and to develop improved detectors. Our main focus is on the GridPix detectors, which we will fabricate using photolithographic processes in the clean rooms of the research building Technologiezentrum Detektorbau (FTD). In addition, we are also experimenting with completely new detector concepts, new materials or readouts.

Aufklapp-TextElectronics and programs adapted to the application and to the detector chips are required for the control and readout of our detectors. For this purpose, we develop our own hardware, software and firmware and make them available to other research groups and collaboration partners. Currently we develop and support systems for detectors with Timepix3, VMM3a and Timepix chips. Furthermore, we are working on possibilities for real-time data analysis and data reduction in the readout system. In addition, we are developing other control systems that are needed to operate our detectors. These include a gas system that ensures constant gas flow and pressure in the detectors and a universal monitoring system for voltages, temperatures and other gas parameters.

Due to their low-cost production and simple visualization of physical processes, gas-filled detectors are also suitable as example detectors in teaching at university, highschool and events for the general public. In order to cover the different applications and to demonstrate the different principles of operation, we are working on very different detectors including classical detectors like wire chambers, spark chambers or cloud chambers. In this area, the focus is not only on the detectors themselves, but also on the didactic concepts that are used to teach the detection principle and particle physics in general.

This worldwide collaboration of nearly 90 institutes is dedicated to the development of microstructured gas-filled detectors. Equipped at CERN with their own laboratory and test beam infrastructure, members work on a variety of different experiments, exchange experiences and develop necessary systems such as readout electronics, gas systems or simulation software, which are shared as a common good and used in many fields.

The Medipix collaborations develop the Medipix and Timepix readout ASICs and associated readout systems. The use of these ASICs ranges from particle physics experiments such as LHCb and measurement instruments for particle accelerators, to neutron detectors in imaging and X-ray detectors in medical applications.