Callio lab: an underground and above ground,laboratory—overview and prospects for high energy and applied physics

This overview provides a comprehensive insight into Callio Lab, a versatile multidisciplinary research platform, by describing the events and actions that have led to the development of the project-based, pay-by-service approach to organizing and economically running the research activities, a mandatory approach for a platform operating without governmental funding. The research platform has a maximum depth of 1.4 km underground, equivalent to approximately 4,100 m of water equivalent (m.w.e.). The flat-overburden mine configuration of Callio Lab minimizes cosmic-ray background interference, making it an ideal setting for low-background experiments, particularly in neutrino and dark matter research. The main-level galleries, with dimensions up to 12 m wide, 30–40 m long, and 8 m tall, provide ample space for research activities, with the potential for even more extensive galleries based on Laguna design studies. Callio Lab has a history with several small and medium-scale cosmic ray and low-background experiments. This overview highlights the site’s inherent characteristics, revealing promising opportunities for high-energy and applied physics research and applications across various scientific domains

Atmospheric muography for imaging and monitoring tropic cyclones

Large-scale solid bodies on Earth such as volcanoes and man-made pyramids have been visualized with solid earth muography, and the recently invented technique, acqueous muography, has already demonstrated its capability to visualize ocean tides and tsunami. In this work, atmospheric muography, a technique to visualize and monitor the vertical profile of tropic cyclones (TCs) is presented for the first time. The density distribution and time-dependent behavior of several TCs which had approached Kagoshima, Japan, has been investigated with muography. The resultant time-sequential images captured their warm cores, and their movements were consistent with the TC trails and barometric pressure variations observed at meteorological stations. By combining multidirectional muographic images with barometric data, we anticipate that muography will become a useful tool to monitor the three-dimensional density distribution of a targeted mesoscale convective system

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Deeper understanding at Lab 2:the new experimental hall at Callio Lab underground centre for science and R & D in the Pyhäsalmi Mine, Finland

In this work I introduce Callio Lab, an underground centre for science and R & D in the Pyhäsalmi Mine, Finland, and the new underground measurement hall Lab 2. Furthermore I present the world’s deep underground laboratories (DULs). In addition I cover the main sources of the background radiation for underground laboratories including their effects to specific low background research topics. As a case study I describe the required steps for the concretisation of a deep underground measuring hall and the methods to reduce the radiative background in Lab 2, especially related to radon. Callio Lab is one of the few deep underground laboratories in the world offering facilities with over-burden of more than 2 000 m.w.e (metres water equivalent), maximum being at 4 000 m.w.e. The deepest currently operating facilities are in Canada (SNOLab, 6 000 m.w.e.) and China (JingPing underground laboratory, 6 800 m.w.e.). The new experimental hall Lab 2 is located at the depth of 1 430 m (approx. 4 000 m.w.e.) in the Pyhäsalmi Mine. The overburden makes the Lab 2 an optimal site for low (muon) background experiments. The value is based on the measurements presented in the Measurements of muon flux in the Pyhäsalmi underground laboratory (T. Enqvist et al., NIM A 554, 2005). Lab 2 was finished during the spring 2016. The Lab 2 consists of two halls: the entrance hall (120 square metres) for handling cargo and the experimental hall (120 square metres). My involvement in the realization of the Lab 2 started in spring 2015 with the preliminary design and ended with the final design. During the design phases I contacted several Finnish suppliers to find documented, low background construction materials to be used in the construction. At the end of the construction I was also involved in the instrumentation of the experimental hall. In the preliminary design the idea was to build a low background experimental hall using low background materials. As these materials were rather expensive the requirements had to be lowered. The main background source in the Lab 2 is the shotcrete walls and the ceiling due to relatively high concentration of uranium and thorium in the additive used in the concrete. Radon, Rn-222, emanating from the surrounding rock and concrete is the biggest challenge for the low background experiments. The radon is radioactive, noble gas and it can diffuse into every setup. The problem comes with the radioactivity of radon, as also the progenies of radon are radioactive all the way to the stable Pb-206. Other DULs have also been challenged by the radon contamination, and several methods have been developed to mitigate the radon levels. Based on the example radon traps presented in the Low background techniques and experimental challenges for Borexino and its nylon vessels (A. Pocar, Ph. D. Thesis, Princeton University, 2003), a decision was made on the type of a radon trap most suitable for Lab 2. I made a schematic design for an active radon trap, a pressure swing adsorption filter. Although first experiment, C14, is already using the Lab 2, background screening of the site has to be performed to fully understand the different background sources. This would help to define what kinds of experiments are feasible to be hosted in the Lab 2, and to define the types and thicknesses of radiation shielding needed for these experiments

Trends in publishing muography related research:the situation at the end of 2020

Abstract Cosmic-ray muography is a novel method for density characterization of gaseous, solid, and liquid materials in various dimensions and with numerous distinct technologies. The number of applications of muography is on a constant rise, as is also the number of authors, affiliations, journals, publishers, funding agencies, and countries that can be related to muography literature. We have applied the Web of Science global citation database to collect statistics of muography-related publications to draw a snapshot of where muography was at the end of 2020, how it got there, and where the current trends may get it in the future

Trends in publishing muography related research results:the situation at the end of 2020

Abstract Cosmic-ray muography is a novel method for density characterization of gaseous, solid, and liquid materials in various dimensions and with numerous distinct technologies. The number of applications of muography is on a constant rise, as is also the number of authors, affiliations, journals, publishers, funding agencies, and countries that can be related to muography literature. We have applied the Web of Science global citation database to collect statistics of muography-related publications to draw a snapshot of where muography was at the end of 2020, how it got there, and where the current trends may get it in the future

Muography, outreaching, and transdisciplinarity:toward the golden age of muography

Abstract We demonstrate that cosmic-ray muography is a fundamentally multidisciplinary research field requiring an outreaching and transdisciplinary approach to support and speed up its current positive growth stage. The transit from expert-driven multidisciplinary research to interdisciplinary and transdisciplinary research requires publishing and promoting muography on multiple fronts and languages. Still, as the rewards for the muography community are likely great indeed, we call for collaborative actions and a change in the research strategy paradigm. Due to this end, we suggest a list of task points for the presentday muography community to get muography better acknowledged and as appealing as possible for the newcomers interested in developing muography or applying it in their respective applications