No Arabic abstract
Advanced detector R&D requires performing computationally intensive and detailed simulations as part of the detector-design optimization process. We propose a general approach to this process based on Bayesian optimization and machine learning that encodes detector requirements. As a case study, we focus on the design of the dual-radiator Ring Imaging Cherenkov (dRICH) detector under development as part of the particle-identification system at the future Electron-Ion Collider (EIC). The EIC is a US-led frontier accelerator project for nuclear physics, which has been proposed to further explore the structure and interactions of nuclear matter at the scale of sea quarks and gluons. We show that the detector design obtained with our automated and highly parallelized framework outperforms the baseline dRICH design within the assumptions of the current model. Our approach can be applied to any detector R&D, provided that realistic simulations are available.
Particle IDentification (PID) is a central requirement of the experiments at the future EIC. Hadron PID at high momenta by RICH techniques requires the use of low density gaseous radiators, where the challenge is the limited length of the radiator region available at a collider experiment. By selecting a photon wavelength range in the far UV domain, around 120 nm, the number of detectable photons can be increased. Ideal sensors are gaseous Photon Detectors (PD) with CsI photocathode, where the status of the art is represented by the MPGD-based PDs at COMPASS RICH. Detector optimization is required for the application at EIC. Here we report about a dedicated prototype where the sensor pad-size has been reduced to preserve the angular resolution. A new DAQ system based on the SRS readout electronics has been developed for the laboratory and test beam studies of the prototype.
This report describes the physics case, the resulting detector requirements, and the evolving detector concepts for the experimental program at the Electron-Ion Collider (EIC). The EIC will be a powerful new high-luminosity facility in the United States with the capability to collide high-energy electron beams with high-energy proton and ion beams, providing access to those regions in the nucleon and nuclei where their structure is dominated by gluons. Moreover, polarized beams in the EIC will give unprecedented access to the spatial and spin structure of the proton, neutron, and light ions. The studies leading to this document were commissioned and organized by the EIC User Group with the objective of advancing the state and detail of the physics program and developing detector concepts that meet the emerging requirements in preparation for the realization of the EIC. The effort aims to provide the basis for further development of concepts for experimental equipment best suited for the science needs, including the importance of two complementary detectors and interaction regions. This report consists of three volumes. Volume I is an executive summary of our findings and developed concepts. In Volume II we describe studies of a wide range of physics measurements and the emerging requirements on detector acceptance and performance. Volume III discusses general-purpose detector concepts and the underlying technologies to meet the physics requirements. These considerations will form the basis for a world-class experimental program that aims to increase our understanding of the fundamental structure of all visible matter
We report the status of R&D on large triple-GEM detectors for a forward tracker (FT) in an experiment at a future Electron Ion Collider (EIC) that will improve our understanding of QCD. We have designed a detector prototype specifically targeted for the EIC-FT, which has a trapezoidal shape with 30.1 degrees opening angle. We are investigating different detector assembly techniques and signal readout technologies, but have designed a common GEM foil to minimize NRE cost for foil production. The assembly techniques comprise either a purely mechanical method including foil stretching as pioneered by CMS but with certain modifications, or gluing foils to frames that are then assembled mechanically, or gluing foils to frames that are then glued together. The first two assembly techniques allow for re-opening chambers so that a GEM foil can be replaced if it is damaged. For readout technologies, we are pursuing a cost-effective one-dimensional readout with wide zigzag strips that maintains reasonable spatial resolution, as well two-dimensional readouts - one with stereo-angle (u-v) strips and another with r-phi strips. In addition, we aim at an overall low-mass detector design to facilitate good energy resolution for electrons scattered at low momenta. We present design for GEM foils and other detector parts, which we plan to entirely acquire from U.S. companies.
We present ion backflow measurements in a Micromegas (MICRO-MEsh GASeous detector) TPC device developed for the next high energy electron-positron linear collider under study and a simple explanation for this backflow. A Micromegas micro-mesh has the intrinsic property to naturally stop a large fraction of the secondary positive ions created in the avalanche. It is shown that under some workable conditions on the pitch of the mesh and on the gas mixture, the ion feedback is equal to the field ratio (ratio of the drift electric field to the amplification field). Measurements with an intense X-ray source are in good agreement with calculations and simulations. The conclusion is that in the electric field conditions foreseen for the Micromegas TPC (drift and amplification fields respectively equal to 150-200 V/cm and 50-80 kV/cm) the expected ion backflow will be of the order of $2 - 3 x 10^-3$. In addition, measurements have been done in a 2T magnetic field: as expected the ion backflow is not altered by the magnetic field.
The use of a nonhomogeneous aerogel radiator, i.e. one consisting of layers with different refractive indices, has been shown to improve the resolution of the Cherenkov angle measured with a proximity focusing RICH detector. In order to obtain further information on the performance of such a detector, a simple model has been used to calculate the resolution and search for optimal radiator parameters.