XENONnT: A Bold Step in Dark Matter Search
Scientists develop innovative methods to detect dark matter through neutrons.
XENON Collaboration, E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad, J. J. Cuenca-García, V. D'Andrea, L. C. Daniel Garcia, M. P. Decowski, A. Deisting, C. Di Donato, P. Di Gangi, S. Diglio, K. Eitel, S. el Morabit, A. Elykov, A. D. Ferella, C. Ferrari, H. Fischer, T. Flehmke, M. Flierman, W. Fulgione, C. Fuselli, P. Gaemers, R. Gaior, M. Galloway, F. Gao, S. Ghosh, R. Giacomobono, R. Glade-Beucke, L. Grandi, J. Grigat, H. Guan, M. Guida, P. Gyorgy, R. Hammann, A. Higuera, C. Hils, L. Hoetzsch, N. F. Hood, M. Iacovacci, Y. Itow, J. Jakob, F. Joerg, Y. Kaminaga, M. Kara, P. Kavrigin, S. Kazama, M. Kobayashi, D. Koke, A. Kopec, H. Landsman, R. F. Lang, L. Levinson, I. Li, S. Li, S. Liang, Y. -T. Lin, S. Lindemann, M. Lindner, K. Liu, M. Liu, J. Loizeau, F. Lombardi, J. Long, J. A. M. Lopes, T. Luce, Y. Ma, C. Macolino, J. Mahlstedt, A. Mancuso, L. Manenti, F. Marignetti, T. Marrodán Undagoitia, K. Martens, J. Masbou, E. Masson, S. Mastroianni, A. Melchiorre, J. Merz, M. Messina, A. Michael, K. Miuchi, A. Molinario, S. Moriyama, K. Morá, Y. Mosbacher, M. Murra, J. Müller, K. Ni, U. Oberlack, B. Paetsch, Y. Pan, Q. Pellegrini, R. Peres, C. Peters, J. Pienaar, M. Pierre, G. Plante, T. R. Pollmann, L. Principe, J. Qi, J. Qin, D. Ramírez García, M. Rajado, R. Singh, L. Sanchez, J. M. F. dos Santos, I. Sarnoff, G. Sartorelli, J. Schreiner, P. Schulte, H. Schulze Eißing, M. Schumann, L. Scotto Lavina, M. Selvi, F. Semeria, P. Shagin, S. Shi, J. Shi, M. Silva, H. Simgen, C. Szyszka, A. Takeda, Y. Takeuchi, P. -L. Tan, D. Thers, F. Toschi, G. Trinchero, C. D. Tunnell, F. Tönnies, K. Valerius, S. Vecchi, S. Vetter, F. I. Villazon Solar, G. Volta, C. Weinheimer, M. Weiss, D. Wenz, C. Wittweg, V. H. S. Wu, Y. Xing, D. Xu, Z. Xu, M. Yamashita, L. Yang, J. Ye, L. Yuan, G. Zavattini, M. Zhong
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Table of Contents
The XENONnT experiment is part of a global effort to hunt for dark matter, specifically a type called weakly interacting massive particles (WIMPs). These elusive particles don't interact with normal matter in the way that, say, a bowling ball interacts with a bunch of pins. Instead, they pass right through us, making them hard to detect. So, the scientists behind XENONnT had to come up with clever ways to catch them in the act, and that’s where the Neutron Veto system comes in.
What’s Dark Matter, Anyway?
Imagine checking your closet for monsters. You might peek in, convince yourself there's nothing there, and go back to bed. Yet, you're not fully at ease. Dark matter is a bit like those monsters—it's a major part of the universe, but try as we might, we can't see it. Scientists know it exists because of its effects, kind of like knowing someone’s eating your leftover pizza just by the empty box.
Although we can’t see it directly, scientists believe dark matter accounts for about 85% of the matter in the universe. That’s like saying you’ve eaten 15% of your pizza, but your buddy consumed the rest! The XENON project aims to find direct evidence of dark matter, focusing on WIMPs.
Why Neutrons?
Here's the twist: searching for WIMPs is like playing hide-and-seek. You can run around and call "Marco!" but all you hear is "Polo!" The background noise, such as neutrons from natural sources, complicates things. They’re a bit like the annoying sounds from the neighbors when you’re trying to focus.
Neutrons are produced from various processes, including the materials that make up the detection equipment itself. These pesky little particles can mimic WIMP signals, leading to confusion. So, the XENONnT team had to come up with a "neutron veto" to keep their results clear. Think of it like putting on noise-cancelling headphones—suddenly, the unwanted background sounds are gone, and you can focus on the task at hand.
What is the Neutron Veto?
The neutron veto system is essentially a water tank equipped with detectors. It works by detecting neutrons that are captured in the surrounding water. The main ingredient of this system? Gadolinium. This special element captures neutrons and produces visible light, which the detectors can pick up.
The setup is pretty cool! The XENONnT facility has a gigantic water tank, which serves as a shield. The water captures some of those sneaky neutrons, allowing scientists to concentrate on the real deal—the WIMPs.
The Importance of Water
Water is a crucial player in this drama. It not only acts as a shield but also allows neutrons to interact. Think of it as a swimming pool where motion is dampened. Neutrons travel through the water, lose energy, and eventually get captured by the hydrogen atoms in the water.
In the first science run, the experiment relied on demineralized water, which means all the minerals (and potential distractions) have been filtered out. This allows for cleaner detection signals. It’s like those fancy drinks that promise to be free from added sugar—no unnecessary stuff to interfere with the taste!
How Does It Work?
The neutron veto employs a technique to tag neutron events. When neutrons are captured in the water, they produce gamma rays. These gamma rays create a flash of light, called Cherenkov Radiation, which is picked up by detectors. It’s like turning on the lights in a dark room—you know something’s happening!
The neutron veto system measures how well it captures these neutrons. The scientists reported an impressive efficiency of detecting these elusive particles, becoming the champion of neutron detection in water. So, if you're looking for someone who does their job well, these detectors might be your new best friends!
Counting Success
During the first official run of XENONnT, the team found a way to efficiently tag and count the neutrons, making the background noise less annoying. They used a combination of techniques, including the timing of signals from both the main detector and the neutron veto, to figure out what was actually happening.
In a nutshell, if a neutron gets caught and says, "Hey, I've been detected!" this whole system ensures it gets noticed. The smart scientists have worked hard to ensure that when they find a signal, they know exactly what they are detecting.
The Challenges of Detection
Despite their amazing work, the researchers faced challenges. Sometimes, neutrons might leave the detector area before being captured. It's like a cat slipping out the door when you finally think you've caught it. The team worked hard to minimize this loss of useful data, balancing the efficiency of detection with the time it takes for neutrons to be captured.
To track the neutrons more effectively, the experiment adjusted the "tagging window," which is the time frame during which a neutron signal is considered valid. The first science run used a short window but proved efficient; they could capture enough data within this timeframe to make meaningful conclusions.
The Neutron Capture and Tagging Process
To assess how well their setup was working, the researchers used calibration sources that emitted neutrons. By understanding how these neutrons interacted with the water, they were able to evaluate the detector's efficiency more accurately. It was like practicing with a baseball before the big game—getting a sense of what kind of pitches to expect.
Results and Findings
The XENONnT experiment has already shown promising results. The neutron veto system demonstrated a high detection efficiency, achieving a rate higher than what has been previously recorded in similar setups. The team was able to confirm that their system was effective at identifying neutron signals efficiently.
More significantly, the researchers managed to tag events that mimicked WIMP signatures fully. This means they can potentially rule out background noise from natural sources, giving them a clearer path to finding actual dark matter.
Moving Forward
The project won't stop here. The researchers are always looking for ways to improve their results. They plan to enhance the neutron veto system further by adding gadolinium to the water, which will help capture neutrons more effectively. It’s like adding a secret ingredient to grandma’s famous recipe—everyone expects it will make things even tastier!
With the new enhancements, they aim to increase both the detection and tagging efficiency further. This second phase of the experiment is expected to yield even more exciting results, leading the team deeper into the search for dark matter.
Imagine the thrill of uncovering the universe's hidden secrets! If successful, they could unlock a wealth of knowledge about the cosmos and what really makes it tick.
Conclusion: A Bright Future Ahead
In summary, the XENONnT project has made significant strides in dark matter research. Their neutron veto system is a clever way to filter out background noise and focus on the true culprits—the WIMPs. As they continue their work and improve their techniques, we might just be on the cusp of discovering something monumental about the universe.
Who would have thought that the quest for dark matter would lead to exciting adventures with water tanks, neutrons, and clever detection techniques? With researchers dedicated to unraveling the universe's mysteries, the future looks bright—perhaps even brighter than the Cherenkov light in their detectors!
Original Source
Title: The neutron veto of the XENONnT experiment: Results with demineralized water
Abstract: Radiogenic neutrons emitted by detector materials are one of the most challenging backgrounds for the direct search of dark matter in the form of weakly interacting massive particles (WIMPs). To mitigate this background, the XENONnT experiment is equipped with a novel gadolinium-doped water Cherenkov detector, which encloses the xenon dual-phase time projection chamber (TPC). The neutron veto (NV) tags neutrons via their capture on gadolinium or hydrogen, which release $\gamma$-rays that are subsequently detected as Cherenkov light. In this work, we present the key features and the first results of the XENONnT NV when operated with demineralized water in the initial phase of the experiment. Its efficiency for detecting neutrons is $(82\pm 1)\,\%$, the highest neutron detection efficiency achieved in a water Cherenkov detector. This enables a high efficiency of $(53\pm 3)\,\%$ for the tagging of WIMP-like neutron signals, inside a tagging time window of $250\,\mathrm{\mu s}$ between TPC and NV, leading to a livetime loss of $1.6\,\%$ during the first science run of XENONnT.
Authors: XENON Collaboration, E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad, J. J. Cuenca-García, V. D'Andrea, L. C. Daniel Garcia, M. P. Decowski, A. Deisting, C. Di Donato, P. Di Gangi, S. Diglio, K. Eitel, S. el Morabit, A. Elykov, A. D. Ferella, C. Ferrari, H. Fischer, T. Flehmke, M. Flierman, W. Fulgione, C. Fuselli, P. Gaemers, R. Gaior, M. Galloway, F. Gao, S. Ghosh, R. Giacomobono, R. Glade-Beucke, L. Grandi, J. Grigat, H. Guan, M. Guida, P. Gyorgy, R. Hammann, A. Higuera, C. Hils, L. Hoetzsch, N. F. Hood, M. Iacovacci, Y. Itow, J. Jakob, F. Joerg, Y. Kaminaga, M. Kara, P. Kavrigin, S. Kazama, M. Kobayashi, D. Koke, A. Kopec, H. Landsman, R. F. Lang, L. Levinson, I. Li, S. Li, S. Liang, Y. -T. Lin, S. Lindemann, M. Lindner, K. Liu, M. Liu, J. Loizeau, F. Lombardi, J. Long, J. A. M. Lopes, T. Luce, Y. Ma, C. Macolino, J. Mahlstedt, A. Mancuso, L. Manenti, F. Marignetti, T. Marrodán Undagoitia, K. Martens, J. Masbou, E. Masson, S. Mastroianni, A. Melchiorre, J. Merz, M. Messina, A. Michael, K. Miuchi, A. Molinario, S. Moriyama, K. Morá, Y. Mosbacher, M. Murra, J. Müller, K. Ni, U. Oberlack, B. Paetsch, Y. Pan, Q. Pellegrini, R. Peres, C. Peters, J. Pienaar, M. Pierre, G. Plante, T. R. Pollmann, L. Principe, J. Qi, J. Qin, D. Ramírez García, M. Rajado, R. Singh, L. Sanchez, J. M. F. dos Santos, I. Sarnoff, G. Sartorelli, J. Schreiner, P. Schulte, H. Schulze Eißing, M. Schumann, L. Scotto Lavina, M. Selvi, F. Semeria, P. Shagin, S. Shi, J. Shi, M. Silva, H. Simgen, C. Szyszka, A. Takeda, Y. Takeuchi, P. -L. Tan, D. Thers, F. Toschi, G. Trinchero, C. D. Tunnell, F. Tönnies, K. Valerius, S. Vecchi, S. Vetter, F. I. Villazon Solar, G. Volta, C. Weinheimer, M. Weiss, D. Wenz, C. Wittweg, V. H. S. Wu, Y. Xing, D. Xu, Z. Xu, M. Yamashita, L. Yang, J. Ye, L. Yuan, G. Zavattini, M. Zhong
Last Update: 2024-12-18 00:00:00
Language: English
Source URL: https://arxiv.org/abs/2412.05264
Source PDF: https://arxiv.org/pdf/2412.05264
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
Thank you to arxiv for use of its open access interoperability.