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TIC meeting - PreTDR draft Version2; update on common sceniarios (luminosity, background)
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Description
Technical and Integration Council Meeting
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https://yale.zoom.us/j/98351531019
Recording available in meeting materials right below:
General reminder: final draft version of pre-TDR due on July 12th.
Please get in touch with the technical coordinator (and/or deputies) if you have any questions on pre-TDR matters.
First contribution by Elke Aschenauer on updated EIC luminosity scenarios (for radiation damage estimates):
- EIC total lifetime defined as 30 years of operation
- ePIC total lifetime assumed as first 15 years of EIC program:
- 5 years of commissioning and ramp-up corresponding to 40fb^-1 total
- 10 years of physics runs at varying beam energy combinations, corresponding to 100 fb^-1 total
- 2 years 5GeV e x 41GeV p
- 1 year 5GeV e x 100GeV p
- 2 years 10GeV e x 100GeV p
- 2 years 10GeV e x 275GeV p
- 3 years 18GeV e x 275GeV p
- for pre-TDR purposes, can assume 10GeV e x 275GeV p as it will have highest luminosities, and thus occupandies, irradiation etc.
Second contribution from Andrii Natochii on updates to beam background estimates:
- updated electron ring lattices now offer sufficient beam lifetimes at 5, 10 and 18GeV
- updated collimator positioning to protect final focus quads and detectors
- beam particle tracking code was updated, beam loss overlay files produced for Coulomb and Touschek scattering
- now including detailed beam pipe pressure profile estimates in IR6 region + constant pressure assumed in rest of ring
- Software group will work on combining both background files into common overlay file
- Further work on hadron beam collimation is ongoing, optimizing collimator placement
- following LHC/FCC approach with primary and secondary collimators
- collimation simulations will be updated with beam pressure profiles and benchmarked vs. well studied LHC models
To be taken with a grain of salt, the Zoom AI companion summary of the meeting:
Meeting summary for TIC Meeting (06/16/2025) Quick recap
The meeting focused on updates regarding the Pre-TDR draft deadline and luminosity calculations for the EIC, with Elke presenting refined models and numbers for the first five years of operation. Natochii provided detailed discussions on electron beam collimation simulations and loss rate distributions, including the implementation of collimators and beam pipe designs. Andre and Natochii shared insights on beam background simulations and vacuum profiles, while Andre highlighted the need for benchmarking against the LHC model before applying it to the EIC.
Next steps
- Vacuum group to provide a more realistic gas pressure profile beyond the IR6 region for Andre's beam loss simulations.
- Andre to finalize implementation of the backward cryostat model in DD4hep and fix overlaps with the older model.
- Andre to continue work on hadron beam collimation, including tuning IR12, studying collimation inefficiency, and investigating failure scenarios.
- Software group to update background merger to potentially combine Touschek and Coulomb samples into one file, while keeping in mind future need for separating multiple background sources.
- Tracking group to analyze mixing samples and provide limits for background rates in the detector region.
Summary
Pre-TDR Draft Deadline Update
Oskar chairs the tech meeting and reminds everyone about the upcoming deadline in July for the final version of the Pre-TDR draft. He mentions that comments have been posted for all DSC subsystems and encourages participants to contact the TC office if they need help locating them. Elke begins her update on common scenarios, stating that she will focus on updated slides with relevant numbers and will not cover backgrounds, as Andre will discuss those in detail later.
Updated Luminosity and EIC Capabilities
Elke presents updated luminosity numbers for the first five years of operation, based on a refined model that accounts for cycle time. The new calculations show slightly higher luminosity per year, with a year defined as six months of operation. Elke also provides numbers for the full EIC capabilities, which will involve increasing the nano column from 7 to 28. For radiation dose calculations, Elke suggests using a 15-year lifetime for the experiment, while the machine itself is designed for a 30-year lifetime. The total integrated luminosity for the first five years is estimated at 40 inverse femtobarns, with adjustments made to beam energy running scenarios.
Electron Beam Collimation Simulation Update
Natochii provides an update on electron beam collimation simulations for the ring. The optimized lattices for 5, 10, and 18 GeV energies offer sufficient beam lifetimes for safe operation. To protect the detector and final focus quadrupoles, collimators will be installed in IR4, the nearest upstream straight section before IR6. The collimation scheme uses betatron collimation with low dispersion and large betatron function, placing a vertical collimator in phase with Q0EF and a horizontal collimator in phase with Q1EF to protect their respective apertures.
IR Collimator Layout and Optimization
Natochii presents the IR section layout, focusing on the placement of collimators downstream of IP.4 and IP.6 to protect the final focus quadrupoles and reduce beam loss. He discusses the implementation of realistic gas pressure distribution in the ESR for beam gas simulations, with a detailed profile for IR.6 and a uniform 5 nanotor pressure assumption for the rest of the ring. Natochii then explains the collimator aperture scans, showing how the beam lifetime and local losses are affected by different aperture settings. He emphasizes the need to find an optimal aperture that minimizes impact on beam lifetime, maximizes loss rate reduction, and minimizes impedance contribution to avoid beam instability.
Particle Tracking Software Framework Update
Natochii discusses the software framework used for particle tracking and loss location refinement in the detector region. He explains the challenges of implementing the racetrack-shaped beam pipe in the tracking code and mentions that the beam pipe design will be updated soon. Natochii presents the loss rate distribution in the detector region and describes how particle samples are prepared for background mixing and tracking performance studies. He compares the raw hit rates for different beam energies and background sources, noting that Touschek and Bremsstrahlung are dominant at 10 GeV and 18 GeV, respectively. Natochii provides information on the location and format of the background files and suggests using Touschek and Coulomb MC samples in addition to the existing background sources for mixing.
Cryostat and Collimation System Updates
Natochii provides an update on two key areas: the cryostat design and the hadron beam collimation system. A new, more detailed cryostat model has been implemented in simulations to study radiation and beam loss effects, which is crucial for accurate detector background simulations. For the hadron beam collimation, they have adopted an approach similar to LHC and FCC, using primary and secondary collimators to manage the beam halo. The team is developing a framework to study collimation performance, including reverse lattice design and particle tracking simulations. Next steps include tuning the IR12 section for collimator placement, studying collimation inefficiency, and installing additional collimators near the detector.
EIC Beam Background Simulation Updates
Andre discusses the ongoing work on beam background simulations for the EIC. He explains that the current pressure profile assumptions are preliminary and will be refined with input from the vacuum group, including more realistic profiles around the detector region. The team plans to extend the simulation upstream by 10-30 meters to accurately model inelastic interactions. Andre notes that local losses from particle scattering on pressure are the predominant source of detector background rates in IR6. He also mentions that the collimation simulation will be updated as the vacuum model and pressure profiles are refined. The team is focusing on benchmarking their framework against the well-studied LHC model before applying it to the EIC.
Understanding Beam Lifetime at Higher Energies
Natochii explains that the beam electron beam lifetime increases for higher energies due to factors such as dynamic aperture, momentum acceptance, and the number of particles in the bunch. He illustrates this concept using a 2D diagram showing the machine's acceptance in horizontal and momentum planes. Oskar expresses appreciation for learning something new. The meeting concludes with thanks to Andre and Elka for their presentations, and Oskar mentions he will summarize the notes and upload the recording.
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