+++
authors = ["Pim Nelissen"]
title = "Developments and Implementation of gamma-ray Tracking in AGATA: A literature review"
date = "2025-05-27"
math = true
+++

{{< notice tip >}} The report is available [here](/files/gamma-ray-tracking.pdf). {{< /notice >}}

# Reflection

As a final project in my Modern Subatomic Physics course, we were to do a small literature review of anything from the course. I decided to write about $\gamma$-ray tracking algoritm development mainly around the European Advanced GAmma Tracking Array AGATA.

# Summary

Out of EUROBALL and GAMMASPHERE, the state of the art High-Purity Germanium detectors of the 20th century, came the development of The Advanced GAmma Tracking Array. AGATA is a European detector array which uses highly segmented HPGe crystals and the concept of $\gamma$-ray tracking to reconstruct the chain of Compton scattering events that $\gamma$-rays in nuclear structure studies can go through before fully depositing their remaining energy in a HPGe crystal through the photoelectric effect. The paper briefly discusses the conceptual background of gamma spectroscopy and its use cases, the different physical interactions of $\gamma$-rays with matter, and the experimental challenges with this type of spectroscopy. The developments that led up to the construction of AGATA are discussed. Followed by this historic overview, physical background and motivation for $\gamma$-ray tracking, the computational procedure and algorithms involved with $\gamma$-ray tracking are discussed in detail. Performance of AGATA with these algorithms is discussed and compared with previous detector setups. On top of that, performance between the different procedures is assessed too. Recent developments in tracking, such as self-calibrating algorithms and graph neural networks, are briefly discussed and compared to existing methods.

# Conclusion

The past 20 years have seen significant development in the space of $\gamma$-ray tracking. From EUROBALL to AGATA with forward tracking, we observed a significant improvement in efficiency and a notable improvement in P/T ratio, but there is room for further improvement. Recent studies using probability based calibration algorithms and neural networks show promising results, but more research needs to be done in order to make progress and further improve the spectroscopic results. Nonetheless, AGATA remains the state of the art γ-tracking detector array with relevancy to today’s nuclear structure studies as well as into the future.
