XXVI DAE-BRNS High Energy Physics Symposium 2024

TCAD simulation study to understand the behaviour of proton irradiated thin LGADs

Not scheduled

20m

Swatantrata Bhavan, Banaras Hindu University, Varanasi

Postar Future experiments and detector development

Speaker

Mr Rajiv Gupta (Banaras Hindu University)

Description

The high luminosity operation of the Large Hadron Collider (HL-LHC) requires radiation hard silicon detectors for precise particle tracking and accurate time stamping of traversing particles. Low Gain Avalanche Detectors (LGADs) offer radiation hard characteristics and excellent time resolution, hence, are planned to be used in future HL-LHC. However, recent studies indicate that the multiplication capability due to the additional gain layer in LGADs significantly degrades with increasing particle fluence, primarily due to trap formation and the acceptor removal mechanism. This degradation is particularly severe due to proton irradiation.
To address this issue, we extended our simulation efforts by applying the Proton Damage Model, initially developed by Delhi Group for PIN diodes, to thin (50 $\mu$m) LGADs. The simulated geometry and doping profile are fine tuned to obtain measured gain layer depletion voltage ($V_{GL}$), full depletion voltage ($V_{FD}$), active thickness (t), end capacitance ($C_{end}$) and gain over a wide range of bias voltages. Our simulation shows that just considering trap defects and the acceptor removal process isn't enough to accurately predict the gain with respect to the PIN diode for a proton-irradiated LGAD. As a result, optimizing the impact ionization parameters for the irradiated case is necessary as different impact ionization models and their coefficients influence the detector gain. The present simulation study tends to establish the proton damage model for thin LGADs in conjunction with the analytically introduced acceptor removal mechanism and optimized impact ionization coefficients at different levels of neutron equivalent fluence of proton irradiation viz., $(4.3\times {10}^{14}$, $1.18\times {10}^{15}$ and $1.55\times {10}^{15}$) 1 MeV $n_{eq}c{m}^{-2}$. This will enhance the ability to predict detector performance in high-radiation environments and contribute to the development of radiation-hard silicon detectors.