## Alexandre S. Göttel M.Sc.

 Alexandre S. Göttel M.Sc. PhD student, joined November 2018 Thesis Title: Solar neutrino detection: CNO discovery with Borexino and preparations for success in JUNO and OSIRIS Contact: Phone: +49 2461 61 4735 E-mail: alexandre.goettel_AT_rwth-aachen.de

### Education

• M.Sc. in Astroparticle Physics and Cosmology
RWTH Aachen University
Master Thesis: Modelling the solar modulation of galactic cosmic-rays

• B.Sc. in Physics
RWTH Aachen University
Bachelor Thesis: Measurement of the cosmic-ray helium spectrum with the transition radiation detector of the Alpha Magnetic Spectrometer (AMS-02) on the international space station

### BOREXINO

Borexino is a well-established liquid scintillator detector. With its unprecedented radiopurity, it has most notably been used to provide a complete spectroscopy of the pp-chain solar neutrinos. More recently, the focus of Borexino shifted to the potential for a discovery of CNO neutrinos. For this purpose a special thermal insulation campaign was launched in 2015 which stabilised the innermost parts of the detector in order to maximise our chances of measuring those elusive solar particles. My work with Borexino contributed to this discovery, which was finally published on the front page of Nature.
• Pile-up estimations with Monte-Carlo techniques
• Development of a Bayesian inference framework using Markov-Chain-Monte-Carlo methods
• Analysis of the so-called "Low-Polonium-field" to determine the rates of $^{210}$Bi, the main background in the CNO analysis

### JUNO

JUNO's enormous target mass will provide the solar nuclear and neutrino science communities with a great opportunity to accumulate a lot of statistics. Indeed, JUNO is expected to measure more neutrino events in a few months that Borexino has in its entire 10+ year lifetime! Our goal is to study JUNO's potential in measuring those neutrinos, to get a quantitative idea of the precision we can expect, and the conclusions we might be able to reach.
• Researching JUNO's sensitivity to solar neutrinos
• Background estimation
• Statistics, spectral fit techniques
• Lead a small team to develop the software used to calculate JUNO's sensitivity
• Data (bit)rate estimation

### OSIRIS

In order to be able to measure solar neutrinos with JUNO, one needs a very radio-pure Liquid Scintillator (LS) and a firm grasp on the different internal (and external) sources of background. The OSIRIS pre-detector for JUNO hopes to set an upper-limit on the Uranium and Thorium contamination of the LS, and can also be used to constrain backgrounds which are relevant to JUNO's solar analysis.
• Geant4-based c++ software development
• Data analysis from Geant4 simulations with ROOT and Python, to investigate different calibration systems and scenarios, and to help decide on mechanical details and achieve physics goals.
• LabView software development and mechanical/hardware work with the calibration systems related to the "Automated Calibration Unit" which was taken over from the Daya Bay Experiment in China. The ACU is being re-purposed for OSIRIS, with the help of our chinese colleagues in Shanghai.
• Sensitivity studies for the main analysis of OSIRIS, the search for $^{212-214}$Bi-Po coincidences
• Sensitivity studies for the detection of $^{85}$Kr in OSIRIS, that can be used to quickly find e.g. air leaks in the system
• Simulation of external backgrounds for the Serappis experiment, a possible future extension of OSIRIS.
• Organisation for on-site activities related to calibration

### Working at IKP

Next to my work with the different experiments I feel very lucky to be part of such a dynamic and varied group. In no small part my work has worked thanks to them, and I can only hope to have had a positive impact on them as well. I have been PhD representative for our institute in the past two years, making sure to communicate between the research center and the doctoral students. Further, I have been maintaining our group website, which serves as a kind of central repository to keep track of our scientific achievements as well as group experiences.

### Conference Talks

• DPG-Frühjahrstagung - March 21-25, 2022 - virtual
Parallel talk: JUNO physics potential and status
• 2021 European Physical Society Conference on High Energy Physics - July 26-30, 2021 - virtual
Parallel talk: JUNO potential in non-oscillation physics
• DPG-Frühjahrstagung - March 15-19, 2021 - virtual
Parallel talk: Calibrating OSIRIS: A 20-ton radioactivity monitor for JUNO
• XIX International Workshop on Neutrino Telescopes - Feb 18-26, 2021 - virtual
Parallel talk: Data analysis of a low-polonium-field for the discovery of CNO neutrinos in Borexino
• DPG-Frühjahrstagung - March 25-29, 2019 - Aachen, Germany
Parallel talk: Calibrating the OSIRIS pre-detector - A radioactivity monitor for JUNO

### Posters

• 2021 European Physical Society Conference on High Energy Physics - July 26-30, 2021 - virtual
A. Göttel: JUNO potential in non-oscillation physics
• The 1st INFN International School on Underground Physics (SoUP 2021) - June 28 - July 2, 2021 - virtual
A. Göttel: JUST: a neutrino fit software for JUNO's solar analysis & sensitivity, accepted for publication in PoS
• The XXIX International Conference on Neutrino Physics and Astrophysics - June 22 - July 2, 2020 - virtual
A. Göttel: OSIRIS - A 20 ton liquid scintillator detector as a radioactivity monitor for JUNO

### Schools

• The 1st INFN International School on Underground Physics (SoUP 2021) - June 28 - July 2, 2021 - Virtual

### Workshop participations

• Programming in C++ - November 2-6, 2020 - Virtual
• Big Data Science in Astroparticle research - February 17-19, 2020 - RWTH Aachen
• Tutorial teaching - April 26, 2017 - RWTH Aachen