Investigations of the long-term stability of a GEM-TPC

For the International Large Detector (ILD) at the planned International Linear Collider (ILC), a Time Projection Chamber (TPC) is foreseen as the main tracking detector. The gas amplification will be done by Micro Pattern Gaseous Detectors (MPGD). One option is to use Gas Electron Multipliers (GEM). While the applicability of GEMs for the gas amplification in a TPC readout has been shown, the focus of the current research is to improve the stability and reliability of the readout modules. This is a crucial requirement for the operation in the final ILD TPC. This presentation shows results from precise discharge current measurements and parallel optical investigations. Ways to improve the long-term stability of the amplification system have been studied

Investigations of the long-term stability of a Gas Electron Multipliers and double hit resolution for the highly granular Time-Projection Chamber

For the International Large Detector (ILD) at the planned International Linear Collider (ILC) a Time Projection Chamber (TPC) is foreseen as the main tracking detector. The TPC will have a single-point resolution of 100 µm in Rphi and 0.4-1.4 mm along the Z axis. The endcap will contain about 240 readout modules. Micro Pattern Gaseous Detectors (MPGD) will be used for gas amplification. The Large Prototype TPC was designed for testing existing and new technologies in conditions as close as possible to those in the ILD TPC. The first part of the studies presented here is devoted to detailed simulations of the response function of the pad-based readout and a triple Gas Electron Multiplier (GEM) stack as a gas system. If the number of activated pads is less than three, the point resolution degrades. This effect may be corrected by applying corrections derived from a fit with the expected Pad Response Function.The second part focuses on the two-hit resolution as a function of the distance between two tracks. It is studied for different track-finding and hit-splitting algorithms for both simulated and experimental data. The main focus of the last part is on studies of the discharge stability and operational features of large-area (22x18 cm²) GEM foils. The effect of voltage oscillations after discharge is studied. The comparison of voltage profiles and Fourier transformations of experimental and simulation data allows the discharge resistance to be estimated (0.6 Ohm). The voltage oscillations have been recognized as a trigger for subsequent discharges (with nanosecondscale time differences). The growth of a resistive oxide layer on top of a GEM surface has been introduced and studied as a method of GEM protection

Latest Results from a TPC Test Beam with a triple GEM Module

End of 2016, a test beam with 3 triple GEM readout modules was performed at DESY. Apart from technical improvements of the modules, the focus of the measurements was to study the double hit resolution and the dE/dx capabilities of the system. The latest results from the ongoing analysis are presented

Double-hit separation and dE/dx resolution of a time projection chamber with GEM readout

A time projection chamber (TPC) with micropattern gaseous detector (MPGD) readout is investigated as main tracking device of the International Large Detector (ILD) concept at the planned International Linear Collider (ILC). A prototype TPC equipped with a triple gas electron multiplier (GEM) readout has been built and operated in an electron test beam. The TPC was placed in a 1 T solenoidal field at the DESY II Test Beam Facility, which provides an electron beam up to 6 GeV/c. The performance of the readout modules, in particular the spatial point resolution, is determined and compared to earlier tests. New studies are presented with first results on the separation of close-by tracks and the capability of the system to measure the specific energy loss dE/dx. This is complemented by a simulation study on the optimization of the readout granularity to improve particle identification by dE/dx

Double-hit separation and dE/dx resolution of a time projection chamber with GEM readout

A time projection chamber (TPC) with micropattern gaseous detector (MPGD) readout is investigated as main tracking device of the International Large Detector (ILD) concept at the planned International Linear Collider (ILC). A prototype TPC equipped with a triple gas electron multiplier (GEM) readout has been built and operated in an electron test beam. The TPC was placed in a 1 T solenoidal field at the DESY II Test Beam Facility, which provides an electron beam up to 6 GeV/c. The performance of the readout modules, in particular the spatial point resolution, is determined and compared to earlier tests. New studies are presented with first results on the separation of close-by tracks and the capability of the system to measure the specific energy loss dE/dx. This is complemented by a simulation study on the optimization of the readout granularity to improve particle identification by dE/dx.Comment: 28 pages, 27 figure

Double-hit separation and dE/dx resolution of a time projection chamber with GEM readout

A time projection chamber (TPC) with micropattern gaseous detector (MPGD) readout is investigated as main tracking device of the International Large Detector (ILD) concept at theplanned International Linear Collider (ILC). A prototype TPC equipped with a triple gas electron multiplier (GEM) readout has been built and operated in an electron test beam. The TPC wasplaced in a 1 T solenoidal field at the DESY II Test Beam Facility, which provides an electron beam up to 6 GeV/c. The performance of the readout modules, in particular the spatial point resolution, is determined and compared to earlier tests. New studies are presented with first results on the separation of close-by tracks and the capability of the system to measure the specific energy loss dE/dx. This is complemented by a simulation study on the optimization of the readout granularity to improve particle identification by dE/dx

Double-hit separation and dE/dx resolution of a time projection chamber with GEM readout

A time projection chamber (TPC) with micropattern gaseous detector (MPGD) readout is investigated as main tracking device of the International Large Detector (ILD) concept at the planned International Linear Collider (ILC). A prototype TPC equipped with a triple gas electron multiplier (GEM) readout has been built and operated in an electron test beam. The TPC was placed in a 1 T solenoidal field at the DESY II Test Beam Facility, which provides an electron beam up to 6 GeV/c. The performance of the readout modules, in particular the spatial point resolution, is determined and compared to earlier tests. New studies are presented with first results on the separation of close-by tracks and the capability of the system to measure the specific energy loss dE/dx. This is complemented by a simulation study on the optimization of the readout granularity to improve particle identification by dE/dx

International Large Detector: Interim Design Report

The ILD detector is proposed for an electron-positron collider with collision centre-of-mass energies from 90~\GeV~to about 1~\TeV. It has been developed over the last 10 years by an international team of scientists with the goal to design and eventually propose a fully integrated detector, primarily for the International Linear Collider, ILC. In this report the fundamental ideas and concepts behind the ILD detector are discussed and the technologies needed for the realisation of the detector are reviewed. The document starts with a short review of the science goals of the ILC, and how the goals can be achieved today with the detector technologies at hand. After a discussion of the ILC and the environment in which the experiment will take place, the detector is described in more detail, including the status of the development of the technologies foreseen for each subdetector. The integration of the different sub-systems into an integrated detector is discussed, as is the interface between the detector and the collider. This is followed by a concise summary of the benchmarking which has been performed in order to find an optimal balance between performance and cost. To the end the costing methodology used by ILD is presented, and an updated cost estimate for the detector is presented. The report closes with a summary of the current status and of planned future actions

The ILD detector at the ILC

The International Large Detector, ILD, is a detector concept which has been developed for the electron-positron collider ILC. The detector has been optimized for precision physics in a range of energies between 90 GeV and 1 TeV. ILD features a high precision, large volume combined silicon and gaseous tracking system, together with a high granularity calorimeter, all inside a 3.5 T solenoidal magnetic field. The paradigm of particle flow has been the guiding principle of the design of ILD. In this document the required performance of the detector, the proposed implementation and the readiness of the different technologies needed for the implementation are discussed. This is done in the framework of the ILC collider proposal, now under consideration in Japan, and includes site specific aspects needed to build and operate the detector at the proposed ILC site in Japan