BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:CIDeR-ML General Meeting DTSTART:20260925T000000Z DTEND:20260925T010000Z DTSTAMP:20261007T092800Z UID:indico-event-10735@indico.slac.stanford.edu DESCRIPTION:https://u-tokyo-ac-jp.zoom.us/j/83932834349Link to recording\n  \n\n\nQuick recap\nThis meeting focused on updates and discussions regar ding simulation improvements for the SK detector using LUCiD software. Riy a presented her work on creating a faster simulation method that reproduce s SKDETSIM results\, showing good agreement between LUCiD and SKDETSIM in terms of photoelectron predictions and event displays. She identified a PM T geometry mismatch between LUCiD's spherical model and SKDETSIM's more co mplex donut-shaped model\, which affects time-of-flight comparisons\, and discussed plans to implement proper PMT geometry modeling. Omar presented multiple fixes for simulation issues\, including improvements to the SIREN energy parameterization using a degree 7 polynomial fit in log space\, co rrections to photon deposition on sensors behind walls\, and adjustments t o overlap calculations. He also discussed ongoing work on implementing ful l 3D geometry in LUCiD\, which would enable extensions to other detector c onfigurations like Juno. Junjie reported on hyperparameter optimization fo r their model\, finding that model depth impacts visibility and T0 predict ion performance. The team discussed plans for the upcoming Doraemon meetin g in Kyushu\, where they will listen to a presentation at 9:00.\nNext step s\nRiya\n\nInvestigate and fix the PMT geometry mismodeling issue in LUCiD \, considering the effect of reflections and gradients. Consult with Omar for the best approach.\nRepeat the tests with Mie scattering and reflectio n physics enabled\, while disabling other water physics.\nBegin to include gradient checks in the simulation tests.\n\nJunjie\n\nFinalize the traini ng of the model for the paper and document the findings and limitations.\n \nOmar\n\nPush the code with the fixes (fixes 1 and 2) to the main branch of LUCiD and notify the team in Slack when it's done.\nContinue working on the full 3D geometry implementation for LUCiD (LUCiD 2.0) and keep the te am updated.\n\nSummary\nLUCiD Simulation Method Updates\nRiya presented up dates on her work to create a faster simulation method with LUCiD that rep roduces SKDETSIM results\, including matching laser emission models and im plementing proper reflection models. She demonstrated that the number of p redicted photoelectrons and event displays between LUCiD and SKDETSIM were very similar\, with small charge differences per PMT. Riya also discussed time-of-flight comparisons\, noting some differences due to a Gaussian ti ming mixture in SKDETSIM based on PMT photon hit timing structure.\nPMT Ge ometry Model Discrepancy\nRiya presented her work on modeling photon detec tion in a detector simulation\, identifying a significant difference betwe en LUCiD's spherical PMT model and SKDETSIM's more complex donut-shaped mo del\, particularly in the top cap region. She implemented a temporary fix using weighted acceptance based on arrival angles but acknowledged this ap proach may not be optimal. The team discussed that properly addressing the PMT geometry mismatch would require either changing the shape model or im plementing a custom PMT model\, with considerations for how different geom etric models might affect gradient calculations and backward path function ality in the simulation.\nPMT Simulation Gradient Checks\nThe team discuss ed implementing gradient checks and geometric modeling for PMT simulations . Omar suggested using an imaginary spherical enclosure around PMTs to per form proper checks\, which would make simulations slightly slower but impr ove gradient accuracy. Riya agreed to focus next on implementing reflectio ns\, acknowledging that changing the PMT geometry would require modifying the reflection model. The group noted that while the current empirical fit approach may handle small effects\, it's important to properly assess the impact of these geometric changes before determining their significance.\ nSIREN Energy Parameterization Updates\nOmar presented changes to the SIRE N energy parameterization\, explaining that the original power law approac h had mismatches at low energies that created energy bias in reconstructio n. They replaced the power law with a degree 7 polynomial in log space\, a chieving errors on the order of 0.1% and improving reconstruction results for the first few energy bins. The next steps include putting the updated parameterization on GitHub and eventually integrating it into the SIREN fi le process.\nSimulation Physics Challenges and Fixes\nOmar discussed chall enges with multiple contradictory effects in their simulation\, particular ly focusing on a physics difference where photons were redepositing into P MTs after reflection\, causing about 5-6% charge change. This issue was id entified and fixed. The team also addressed a second case involving photon hits at grazing incidents that could contribute to multiple sensors\, whi ch was capped to one contribution. Additionally\, Omar mentioned a small c harge bias from sim scaling that required adjusting the overlap width and changing the calculation to use float64 for the overlap table.\nLUCiD Phot on Deposition Fixes\nOmar presented fixes for photon deposition issues in LUCiD\, categorizing them into two groups with Fix 2 being more problemati c due to gradient issues. The fixes were shown to improve momentum unbiase dness but slightly worsen position and T0 predictions. Omar indicated the code would be pushed to the main branch that day and confirmed it would be safe for Riya to use for upcoming tests. Omar also mentioned ongoing work on full 3D geometry implementation\, which could take a few weeks to comp lete\, and discussed plans to help implement LUCiD for JUNO with actual 3D geometry.\n\n\n\nhttps://indico.slac.stanford.edu/event/10735/ URL:https://indico.slac.stanford.edu/event/10735/ END:VEVENT END:VCALENDAR