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Katharina Lachner


Cross-Section Measurement with Calorimetric Variables
  • The main interaction in the energy range of the T2K beam is via charged-current quasi elastic scattering (CCQE), which is typically observed as an interaction with a charged lepton and no pions in the final state. My analysis explores the use of calorimetric variables such as the hadronic energy in addition to lepton kinematics as an attempt to investigate the composition of CCQE vs. non-CCQE interactions in the zero-pion sample.
Hardware for T2K Near Detector Upgrade
  • I was lucky to spend a few months on-site in Japan in early 2023 to help with the assembly of the SuperFGD and the preparation of the ND280 for the upgrade. The remaining time of my second year of the PhD was spent at CERN to help with characterisation and calibration of the readout modules for the High-Angle TPCs using the local x-ray test bench.

More details on T2K and the near detector upgrade can be found here.

Trigger Algorithms and DAQ
  • Part of my research is focused on developing a machine learning based trigger targeted at low energy neutrinos at the Hyper-K far detector. A better identification of low energy neutrinos, which only give a very faint signal above noise in the detector, would improve the identification of supernova neutrinos.
  • Additional work related to DAQ includes the development of a sorting algorithm designed for the specifics of Hyper-K raw readout data, as well as a runtime-performance optimised version of the NHits trigger.
Calibration Optics
  • At Warwick, an optics lab is set up for the development of laser light injection devices for the calibration of Hyper-K. Both a collimated and a diffuse light source are required for this purpose, and my work is focused on research and development for the diffusers, with further contribution to quality control during the production phase.

More details on Hyper-K as well as our work on calibration optics can be found here.


L. Ambrosi et al., ‘Characterization of charge spreading and gain of encapsulated resistive Micromegas detectors for the upgrade of the T2K Near Detector Time Projection Chambers’, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 1056. Elsevier BV, p. 168534, Nov. 2023. doi: 10.1016/j.nima.2023.168534. Available:

[with contribution to the published work; for full publication history including collaboration-wide papers see here]

Conference Talks

NuFact 2023: Simulation and reconstruction of neutrino interactions in the upgraded T2K ND280 detector.
25 August 2023, National University of Korea, Seoul, South Korea.

NuXTract 2023: Unbiased reconstruction of calorimetric variables in cross-section analyses.
3 October 2023, CERN.

Photo of myself during re-cabling for the upstream ecal in the ND280 basket.Upstream-ECal re-cabling as part of the preparation for the T2K Near Detector upgrade, March 2023.

Experiments: T2K, Hyper-K

Supervisors: Dr Steve Boyd, Dr Ben Richards

PhD student since October 2021