Monte Carlo Techniques for the Design of Gaseous and Solid-State Detectors

The continuous advancement of simulation tools such as Garfield++ has played a crucial role in the development and understanding of particle detector technologies.
Consequently, it is essential that these modeling tools keep pace with ongoing technological progress. In this seminar, different Monte Carlo (MC) simulation techniques will be discussed for generating charge carrier movement, diffusion, and multiplication in both gaseous and solid-state sensors. For the multiplication process, various (non)-Markovian macroscopic models that solve the Boltzmann equation will be described, along with detailed microscopic tracking of electrons in gas mixtures.
These methods are essential not only for gaseous detectors with internal gain structures—such as Micro-Pattern Gaseous Detectors (MPGDs) and Resistive Plate Chambers (RPCs)—but also for solid-state sensors including Low-Gain Avalanche Detectors (LGADs), Silicon Photomultipliers (SiPMs), and the newly introduced pixel 3D sensors with internal gain. In addition to modeling fluctuations from charged-particle drift in the active medium, the Photoabsorption Ionization and Relaxation (PAIR) model are used to describe Landau fluctuations.

An increasing number of modern detector designs incorporate materials with finite conductivity to achieve objectives such as enhanced robustness, improved spatial precision, and reliable operation at high fluences. Notable examples include resistive Micromegas, µRWELL, Resistive Silicon Detectors (RSDs or AC-LGADs), and 3D Diamond sensors, which belong to the broader MPGD, RPC, and solid-state detector families.
This seminar presents a general method for numerically computing the signals induced in such structures using an extended version of the Ramo-Shockley theorem where Laplace transforms are used to treat materials with finite resistivity. This approach is particularly useful for the aforementioned detector types.

This work is currently an active topic within the DRD collaborations, particularly DRD1 and DRD3. The presented methods, which describe both microscopic interactions within detectors and the resulting macroscopic observables, provide deeper insights into the physics underlying existing detector technologies. Moreover, they can inform and optimize the design of next-generation particle detectors by enabling theoretical performance estimates based on induced signal calculations. These results can, in turn, guide the development of front-end electronics optimized for the specific requirements of future high-energy physics experiments.

Speaker: Dr Djunes Janssens (CERN)

When: 25^th November at 15:30 

Where: Aula Multimediale