JRA6-next-DIS: Challenges for next generation DIS facilities

Development of new Monte Carlo tools and studies of benchmark channels, for e-A collisions at future deep-inelastic experiments (Electron-Ion Collider, EIC). Optimisation of associated detector designs for high-resolution tracking, vertexing, photon, and PID. Read more… Objectives The Electron-Ion Collider (EIC) is the next generation hadron physics facility on our immediate horizon focused on a range of critical questions in QCD that remain unanswered. The combination of extremely high luminosity (up to 1034 cm-2s-1), high polarisation and a wide range of centre-of-mass energies (20-200 GeV for e-p collisions and 10-125 GeV for e-Au) will provide the perfect conditions to search for the onset of gluon saturation, carry out nucleon tomography across the full range of scales—from the quark-gluon sea to the valence regime—and study the effect of the nuclear environment on a colour charge. Its detectors will meet the challenges of high spatial and timing resolution, high efficiency and acceptance and the ability to discriminate between different particle types in these conditions.

Our WP is focused around the efforts of four European institutions, applying their respective expertise to the development of the EIC physics case and the associated design and development of three critical elements of the detectors: highresolution vertexing, affordable, high-resolution tracking and particle identification at large momenta, underpinned by a strong simulation effort to optimise the detector design for the physics goals.

1. High precision Monte Carlo (MC) simulations of the physics processes are essential to design the interaction region, identify the optimal detector configurations and refine their parameters. The experimental success of the EIC depends on the match between the detector capabilities and the physics requirements and on understanding and controlling systematic effects to a degree comparable to, or better, than the statistical uncertainty. To this end, simulations will focus on signatures of gluon saturation and on a number of exclusive and semi-inclusive processes that enable nucleon tomography and the measurement of nuclear PDFs. This dedicated MC effort will define the development of tracking and particle identification (PID) and forms the unifying backbone of this project.
2. Very low ion-back-flow detectors for tracking with TPC: modern time projection chambers (TPCs) used for charged particle tracking in the upcoming sPHENIX experiment at the Brookhaven National Laboratory, or in the future EIC, are designed to operate at high collisions rates. Their main limitation is the amount of positive ions, created during the electron amplification processes that drift back from the readout detectors into the TPC's drift volume (ion backflow, or IBF). Minimising this becomes a priority of TPC design. Our WP proposes innovative modifications to a Micromegas read-out detector. Micromegas detectors are parallel plate gas detectors which consist of two stages: a drift stage coinciding with the TPC drift volume and an amplification stage where an intense electric field is generated by a metallic micro-mesh positioned ~100μm from the readout pads. By integrating additional meshes into the design, we aim to reduce IBF to levels as low as one-per-mille.
3. Photon detectors for particle identification using RICH: reconstruction of many reactions of interest at the EIC depends on the ability to identify particles which cannot be distinguished kinematically at high momenta, such as pions and kaons. In this kinematic regime, particle identification is most effectively achieved with ring-imaging Cherenkov (RICH) detectors, whose performance crucially depends on the photon detection. Experiments at future facilities like the EIC demand the combination of large acceptance with high resolution and the capability to work in a harsh environment, characterised by strong magnetic fields, high rates and significant radiation. This work package proposes to apply innovative technologies to develop cost-effective and radiation-damage resilient photon counters for high-performance large-area RICH detectors. A practical solution carries potential impact on applied fields like Medical Imaging.
4. Depleted MAPS for tracking: the extremely high resolution required for vertex reconstruction in the EIC can be achieved using silicon pixel sensors and our WP proposes to develop a prototype for central and forward / backward tracking and vertexing. The project builds upon work funded by external sources (US EIC Detector R&D programme) and will exploit the advantages of depleted MAPS technologies (DMAPS), where charge is collected by drift, not diffusion, to simultaneously achieve both high spatial resolution and fast timing (~1 ns resolution). Timing is particularly important in a double-polarized e-p collider where all combinations of spin orientations will be present in each fill. The novelty of this proposal addresses the need to develop a low power (hence low mass), fast timing, digital tracking solution which can provide bunch-by-bunch timing information.