Symposium on Science at PAUL (Paarl Africa Underground Laboratory)

14 Jan 2024, 09:00 → 18 Jan 2024, 18:00 Africa/Johannesburg

Du Kloof Lodge, Du Toitskloof Mountains

Fairouz Malek (LPSC-Grenoble, CNRS and UGA, France), Johannes Jacobus Van Zyl (Stellenbosch University (ZA)), Richard Newman (Stellenbosch University, SA)

The Paarl Africa Underground Laboratory (PAUL) is envisaged being established off the Huguenot Tunnel in the Du Toitskloof Mountains, between the towns of Paarl and Worcester in the Western Cape Province of South Africa. PAUL is envisaged to be an underground laboratory with a floor space of about 600 square metres and a total volume of 10240 cubic metres, Ref:  arXiv:2306.12083 [hep-ex] 

The following are some of the research topics being considered at PAUL:

• Dark Matter search
• Ultra-low level radioactivity measurements for climate science
• Double beta-decay search
• Radiation biology
• Studies of antineutrinos from the Koeberg PWR (about 70 km away)

arxiv-paul-22jun23.pdf

Sunday 14 January

12:00 → 17:00 Registration

17:00 → 22:00 Welcome drink and Braai (barbecue)

Monday 15 January

09:00 → 11:00 Welcome and Introductions

Convener: Robert Lindsay (University of the Western Cape)

09:00 Welcome venue and Introduction

Speakers: Richard Newman (Stellenbosch University, South Africa), Rob Lindsay (UWC, South Africa), Shaun Metzler Wyngaardt (Stellenbosch University)

09:30 Scientific research in South Africa and the idea of an ULab

Speaker: Zeblon Vilakazi (Wits University, South Africa)

PAUL_Intro_Vilakazi_01_2024_Record_1.pdf

PAUL_Intro_Vilakazi_01_2024_Record_1.pptx

09:40 DSI

Speaker: Takalani Nemaungani (Chief Director: Astronomy Department of Science and Technology (South Africa))

10:00 The Paarl Africa Underground Laboratory - a status report

The establishment of the Paarl Africa Underground Laboratory (PAUL) off the Huguenot Tunnel, in the Du Toitskloof Mountains, between the towns of Paarl and Worcester in the Western Cape Province, South Africa is proposed. The PAUL conceptual design, engineering design guidelines, project timelines, critical milestones and costing are discussed. An overview of results from a peer-review of the science case for PAUL is also presented.

Speaker: Richard Newman (Stellenbosch University, South Africa)

Newman_paul-ssp-rtn-lu-15jan24-dis.pdf

11:00 → 11:30 Tea or Cofee break

11:45 → 13:25 Capacity building in Africa

Convener: Fairouz Malek (LPSC-Grenoble, CNRS-UGA, France ans Stellenbosch University (ZA))

11:45 Critical success factors in high- technology infrastructure projects: PBMR, SKA and RCP

Critical success factors in high- technology infrastructure projects: PBMR, SKA and RCP

Speaker: Rob Adam (Stellenbosch University, SA)

Rob Adam PAUL 20240115.pdf

12:05 Towards Establishing the Botswana Institute for Nuclear Science and Technology

The Botswana International University of Science and Technology (BIUST) is leading a national project to establish the Botswana Institute for Nuclear Science and Technology (BINST). BINST will consist of accelerator facilities (such as a 3 MV Tandem accelerator and 10 MV electron accelerator) and state-of-the-art laboratory facilities and infrastructure to focus on R&D in sector pertaining to: health, agriculture, manufacturing, mining, water resources management and sanitation. Through the Technical Cooperation program of the International Atomic Energy Agency (IAEA), BIUST is also developing national educational programs in Nuclear Science and Technology for developing specialized human capital for exploiting the planned facilities. This talk will give an overview of the planned facilities, educational programs, and activities to establish BINST.

Speaker: Gregory Hillhouse (Botswana International University of Science and Technology)

Hillhouse - PAUL Symposium Presentation.pdf

12:25 Broaden horizon with nuclear sciences and technology projects in East African region, particularly in Rwanda. (Remote talk)

It is remarkable that sciences and technology improve life in multiple dimensions once properly used. In this regard, especially on the African continent, efforts are being made in promoting peaceful use of nuclear sciences and technology which is very productive in some key sectors such as agriculture and healthcare. A very few African countries already have in place some operating nuclear installation facilities. However, in recent years there is a growing number of countries in Africa that have embarked or considering to embark on developing nuclear programme for socio-economic development. Although challenging due to limited financial and human resources, this initiative opens new doors for education, training, research, and development with people from all over the world. Perspective on status of nuclear programme in East African region, particularly the ongoing project to establish a Center for Nuclear Science and Technology (CNST) in Rwanda, is presented.

Speaker: Joram Ndayishimye (Rwanda Atomic Energy Board (RAEB))

Presentation at PAUL_Joram.pdf

12:45 Overview talk on DULs (and related research) worldwide

Speaker: Aldo Ianni (INFN LNGS)

DULs@SymposiumPAUL.pdf

13:25 → 14:25 Lunch

14:55 → 17:55 Visit to North Bore of Huguenot Tunnel or mountain hike

19:00 → 21:00 Dinner

Tuesday 16 January

09:00 → 11:05 Cosmology and Dark Matter searches

Convener: Lerothodi Leonard Leeuw (University of Johannesburg (ZA))

09:00 Dark Matter in Radio Astronomy

Dark matter is the dominant matter in the Universe. Its particle nature has been confirmed by the X-rays and weak lensing measurements of the bullet clusters. Currently, in the whole spectra of dark matter mass, there are four domains of candidates that arise much interests in theoretical physics and astronomy community: Axion-Like-Particle (ALP, mass in between $10^{-22}\,{\rm eV}$ to $10^{-10}\,{\rm eV}$); Axion dark matter (mass in between $10^{-10}\,{\rm eV}$ to $10^{-2}\,{\rm eV}$); Weakly Interacting Massive Particle (WIMP; mass in between $10^{9}\,{\rm eV}$ to $10^{13}\,{\rm eV}$) and Primordial Black Holes (PBH; mass $\geq 10^{13}\,{\rm eV}$). I will review how can we detect these different particle scenarios by using the South Africa’s MeerKAT and SKA telescopes and what are the current limits from the present constraints. I will also discuss how can we combine astronomical measurements with ground-based indirect detection, such as PAUL.

Speaker: Yin-Zhe Ma

1-YinZheMa.pdf

09:25 Dark Matter searches with the Cryogenic Experiments CRESST and COSINUS

The CRESST experiment is among the most sensitive direct detection dark matter experiments searching for particles in the sub-GeV region. The experiment is based on crystals operated at cryogenic temperatures. The simultaneous read-out of the total deposited energy by collecting phonons and scintillation light allows the separation of signal and background events. The cryogenic technology will also be used for a new dark matter experiment, COSINUS, located at the Gran Sasso underground laboratory in Italy. COSINUS is designed to gain further information on the long-standing annually modulated signal observed by the DAMA/LIBRA experiment. The DAMA/LIBRA experiment measures the scintillation light from NaI crystals produced by elastic dark matter scattering. The earth’s motion around the sun is expected to generate an annual modulation of the dark matter signal. The COSINUS experiment also uses NaI crystals. However, it operated at cryogenic temperatures. Like CRESST, this allows the separation of signal and background events and provides additional information on the signal observed by DAMA/LIBRA.
The location of a COSINUS-like experiment in the southern hemisphere would provide additional information. A dark-matter-induced dark matter signal would be unchanged, while seasonal changes might influence an environmental-induced signal. We will present the cryogenic technology and discuss the latest results from the CRESST experiment. The status of the COSINUS experiment will be shown. The option of a COSINUS twin experiment on the southern hemisphere, COSINUS-SOUTH, will be discussed. Finally, we will report on ongoing R&D activities measuring dark matter-electron scattering with DANAE, which aims to measure single electrons with a semiconductor readout with the DEPFET scheme.

Speaker: Jochen Schieck (Austrian Academy of Sciences (AT))

Symposium_Paul_Schieck.pdf

09:50 The search for dark-matter using H.E.S.S.

The PAUL facility offers a promising environment for the establishment of
direct dark-matter detection experiments. Complimentary to such direct detection
efforts are indirect detection methods, in particular using gamma-ray observations
of dark-matter dominated astrophysical objects, such as dwarf galaxies or the
Galactic halo. The High Energy Stereoscopic System (H.E.S.S.) in Namibia is
conducting such observations as part of its astroparticle-physics program.
This talk will present the current status of indirect dark-matter detection
efforts using H.E.S.S. and other gamma-ray observatories. I will discuss the
current best limits on the dark-matter annihilation cross sections and their complementarity with direct-detection experiments.

Speaker: Markus Boettcher

PAUL2024_HESS_DM_Boettcher.pdf

10:15 Direct-Detection of Sub-GeV Dark Matter: A New Frontier

Direct-detection searches have traditionally focused on Weakly Interacting Massive Particles (WIMPs) with masses above the proton (about 1 GeV/c^2). However, many natural dark-matter candidates have masses below the proton and are invisible in traditional WIMP searches. In this talk, I will provide an overview of the search for particle dark matter with masses between about 1 meV/c^2 to 1 GeV/c^2 (“sub-GeV dark matter”). I will highlight both the tremendous progress made in the past few years as well as the challenges faced by these searches. I will also describe how progress in this area relies on the exciting interplay between various subfields of physics, including particle physics theory and experiment, cosmology, astrophysics, condensed matter physics, quantum sensing, and instrumentation. Finally, I will discuss how PAUL can contribute to this exciting research field.

Speaker: Rouven Essig (Stony Brook University)

Rouven-Essig-PAUL-Symposium.pdf

10:40 Relativistic electrodynamics in a medium

The Lorentz-invariance of Maxwell's equations governing electromagnetism in a vacuum is well-established. This is immediately apparent when these laws can be rephrased in terms of the field strength tensor, four-potential and four-current. Obtaining a manifestly covariant formulation of Maxwell's equations in a medium is however non-trivial. Subtleties related to the Lorentz-invariance of the constitutive relation between the electric and displacement fields arise. We report on various attempts to address these issues in dielectrics. We also discuss their extensions to curved spacetimes. We present some applications to phenomena such as Cerenkov radiation

Speaker: Anslyn John (Stellenbosch University)

AJJ_SSP_2024.pdf

10:55 Perturbation theory in bulk viscous cosmology

The ΛCDM model is currently our best description of the universe. However, the model does not
come without fault as discrepancies between theory and observation have emerged. Bulk viscosity
has been proposed as a possible extension to the ΛCDM model as to account for these mismatches.
We review two alternative scenarios for the study of relativistic dissipative hydrodynamics applied
to cosmological ?uids, namely the Eckart and Muller-Israel-Stewart (MIS) theories. Our objective
is to study the e?ects of bulk viscosity on the formation of large-scale structure via the evolution
of the metric potential and dark matter density perturbations. After reviewing the results from
standard cosmological perturbation theory, we compare the two competing theories for dissipa-
tive hydrodynamics. We investigate changes to the conservation equations as well as the Einstein
equations with the introduction of the bulk viscous pressure. We will then discuss the numerical
solutions found for the evolution of the metric potential as well as comment on the clustering prop-
erties of the dark matter density perturbations. We compare the results from the two competing
theories. We see that for the metric potential, the Eckart and MIS theories deviated from the
ΛCDM case. We comment on nature of current cosmic tensions in this context. Future work is
also discussed.

Speaker: Jaymie Van der Merwe (Stellenbosch University, SA)

Jvdm_SSP_2024_2.pdf

11:05 → 11:35 Tea or Cofee break

11:35 → 13:35 Overiew on Underground Labs research

Convener: Shaun Metzler Wyngaardt (Stellenbosch University)

11:35 The SNOLAB Science Program

Speaker: Jodi Cooley (SNOLAB)

240116_PAUL_symposium.pdf

12:00 Physics at an underground laboratory, LNGS

Speaker: Marcello Messina (LNGS-INFN)

8-Messina_PAULSymposioum.pdf

12:25 Science at Underground Laboratory of Modane (LSM)

The Modane Underground Laboratory (LSM) is located 1700 m (4800 m.w.e) below Fréjus peak (Alpes chain) mountain in the middle of the Fréjus tunnel between France/Italy. This thickness of the rock reduce the muon flux to 5 muons/day/m2. The LSM is a multidisciplinary platform for the experiments requiring low radioactivity environment. Several experiments in Particle and Astroparticle Physics, low-level of High Purity of Germanium gamma ray spectrometry, biology and home land security hosted in the LSM. I’ll present the evolution of the LSM structure and of its science program.

Speaker: Ali DASTGHEIBI FARD (CNRS/LPSC_LSM)

DastgheibiFardSSP2024.pdf

12:50 Boulby Underground Laboratory: Status and plans for the UK’s deep underground science facility

Boulby Underground Laboratory is the UK’s deep underground science facility and one of the few special facilities in the world suited to studies requiring ultra-low background radiation experimental space and/or general access to the deep underground environment. Boulby operates in a working polyhalite and salt mine in the North East of England and hosts a range of science from astroparticle physics (Dark Matter and neutrino studies) to Earth and environmental science, astrobiology and planetary exploration technology development. Boulby also operates its BUGS (Boulby Underground Screening) facility with a range of high sensitivity, ultra low background material screening capabilities. STFC and Boulby Lab are now planning for an expansion of facilities and science at Boulby in the coming decade, working towards a major new facility for next generation astroparticle physics projects and more being available from 2030+. This talk will give details of the current Boulby facility and science, and the planned future expansion.

Speaker: Sean Paling (STFC UKRI, UK)

10-Paling-Boulby_PAUL_Jan2024_v2.pdf

13:15 Underground Lab activities in the Southern Hemisphere

I will discuss the direct search for dark matter within the southern hemisphere, with the SABRE and Cygnus experiments. The SABRE experiment is the first dual-sited direct detection experiment The Northern Hemisphere experiment will be hosted at Laboratori Nazionali del Gran Sasso.

I will also discuss the physics program of the first underground physics laboratory of the Southern Hemisphere, SUPL (Stawell Underground Physics Laboratory) the first-ever integrated underground laboratory in Australia.

Speaker: Elisabetta Barberio (The University of Melbourne, Australia)

11-Barberio-SUPL_PAUL_v1.pdf

13:35 → 14:35 Lunch

14:35 → 17:35 Excursion to the town of Paarl

19:00 → 21:00 Dinner

Wednesday 17 January

09:00 → 10:34 Neutrino Physics

Convener: Fairouz Malek (LPSC-Grenoble, CNRS and UGA, France)

09:00 Neutrino and feebly interacting particle searches at the LHC

The first direct neutrino measurements at the Large Hadron Collider, CERN, have recently been published following a year of data taking of two new small forward detectors, FASER(ν) and SND@LHC. These experiments use both electronic and emulsion based detector components for the measurement of neutrino interactions and long lived particles produced in the very forward region of the proton-proton interacting points. They exploit the unique energies of the LHC’s proton-proton collisions at center-of-mass energies of 13.6 TeV and the high beam intensities to measure physics from a new angle. This talk is an overview of these measurements in the context of the FASER experiment: Its design, technology, and analysis strategy for detection of Standard Model neutrinos and new feebly interacting particles, whilst controlling for the high muon flux background. FASER’s first neutrino-based measurements mark the first observation of muon neutrinos at a collider and the detection of the highest energy electron neutrinos from a human made source.
Once these measurements grow more precise in future analyses, the results will offer useful constraints on neutrino interaction cross-sections and simulation of particle production processes in the forward region. I will remark on the connection between these results and astroparticle physics experiments, such as neutrino telescopes, cosmic ray shower arrays, and dark matter experiments.

Speaker: Claire Antel (Universite de Geneve (CH))

neutrino_talk_PAUL_Symposium_Jan2024.pdf

09:28 Specialized double beta decay experiments and technologies for deep underground laboratories

Deep underground laboratories provide a unique “radiation free” environment for broad range of fundamental and applied research and development, e.g. double beta decay, dark matter detection, innovative detector technologies, radiobiology, geoscience or climatology.

Experiments in deep underground laboratories could be divided into two main groups – i) leading activities in the field (e.g. in double beta decay LEGEND experiment), ii) specialized (smaller) experiments. The present situation and obtained results of two specialized experiments in double beta decay, investigation of 106Cd (2EC/EC decay) by TGV spectrometer (32 HPGe planar type detectors in common cryostat) and investigation of 82Se (2 decays to the first 0+ level of daughter nuclide) by HPGe detector OBELIX (ultra-low background detector with volume of 605 cm3) will be presented.

To reach ultra-low radiation environment in deep underground laboratories it is necessary to install several infrastructural equipment. Important part of background in the deep underground laboratories is caused by radon. The sophisticated filtration anti-radon facility suppressing the content of radon by a factor 2000-3000 (output air with radon activity below 10 mBq/m3) and a clean room (ISO 5) with highly reduced radon concentration (at the level of 10-20 mBq/m3) will be also presented.

Speaker: Ivan Stekl (Institute of Experimental and Applied Physics, Czech Technical University in Prague)

PAUL_IvanS_v2.pdf

09:51 R2D2: a xenon TPC for neutrinoless double beta decay search

The search for neutrinoless double beta decay could cast light on one critical piece missing in our knowledge i.e. the nature of the neutrino mass. Its observation is indeed the most sensitive experimental way to prove that neutrino is a Majorana particle. The observation of such a potentially rare process demands a detector with an excellent energy resolution, an extremely low radioactivity, a capability to identify the 2 emitted electrons and a large mass of emitter isotope. Nowadays many techniques are pursued but none of them meets all the requirements at the same time. The goal of R2D2 is to prove that a cylindrical high pressure TPC filled with xenon gas could meet all the requirements and provide an « ideal » ton-scale detector for the 0νββ decay search. A new prototype has demonstrated an excellent resolution with argon at pressure up to 10 bars. New results with xenon up to 6 bars are very encouraging et confirm the potential of the detector. In the proposed talk the R2D2 results obtained with the last prototype will be discussed as well as the project roadmap and future developments.

Speaker: Fabrice PIQUEMAL (LP2I Bordeaux)

Fabrice-R2D2-PAUL-2024-size.pdf

10:14 A request for a study of beta-decays and the ENIGMA project

Neutrinos remain the most mysterious fundamental particles despite the enormous success accomplished in neutrino physics over the past two decades. The subjects of primary interest are several undeniably basic questions concerning the nature, absolute mass scale, hierarchy, and CP properties of neutrinos and the possible existence of additional sterile neutrinos. The atomic nuclei, probes for studying neutrino fundamental properties and interactions, can uncover neutrino physics tasks in non-trivial ways. The experimental and theoretical study of the beta-decay, double-beta decay, and other nuclear processes can solve many of them. A request to study allowed and forbidden single-beta decay and EC processes is presented by addressing the issues of the neutrino mass, electron exchange effect, and the value of the axial-vector coupling constant. Subjects of interest are beta-transitions known as background processes in underground experiments and those relevant for determining the spectra of reactor antineutrinos. Further, the ENIGMA project is presented, whose primary objective is to approve the concept of an innovative prototype of the reactor antineutrino detector and verify its basic functionality. The detector prototype will utilize scintillation detectors with a Li6F-based scintillator interlayer.

Speaker: Fedor Simkovic (Comenius University and IAEP CTU)

FSimkovic_PAUL_2024.pdf

10:34 → 11:04 Tea or Cofee break

11:04 → 12:56 Ultra-low radioactivity and Radiobiology

Convener: Jacques Marteau (IP2I and Université de Lyon, France)

11:04 Ultra-low radioactivity, a new frontier for biology (Remote talk)

Everywhere there is life, there is radioactivity. Indeed, radioactivity is at the heart of every living organism thank in particular to the presence of potassium 40 with a 1.248 billion years half life and a 0.1167% isotopic fraction. The role radioactivity may have played in the emergence and evolution of life on earth is still a matter of debate. Is the recent discovery in Gabon of multicellular organisms dated 2.1 billion years ago a few kilometers from the Oklo natural nuclear reactors only a mere coincidence or is there a correlation between these two currently unique events in the history of the earth ?

Models for radiation risk in humans have existed for decades. However, there are still debates about what happens at low doses. The currently accepted model of the radiation dose-damage relationship for organisms is the linear no-threshold (LNT) model, which predicts a positive linear correlation between dose and damage that intercepts at zero dose corresponding to zero damage.

Deep Underground Laboratories are unique places to explore the relevance of the LNT model and to challenge its relevance when radioactivity is reduced 10 to 1000 times compared to levels of background radiation typically found in terrestrial surface environments.

The talk will summarize the state of the art of the radiation biology programs currently running in Underground laboratories around the world and propose some directions for a research program at PAUL.

Speaker: Vincent BRETON

2024 01 17 Breton PAUL workshop v1.pdf

11:27 A review of the biological effects of the low-radiation background at deep underground laboratories

Since the late 1980s, the field of astroparticle physics has seen tremendous growth and deep underground laboratories (DULs), the primary infrastructure, have directed the narrative on elementary particles, from lepton flavours to neutrino interactions as well as dark-matter research.
DULs are essential for sensitive experiments that require a low radiation background. This unique environment could have a significant impact on living organisms. Biological studies in extreme environments have shown that prokaryote and eukaryote cells undergo a stress response when exposed to these sub-background radiation conditions, resulting in genetic sensitivity, i.e. a reduced ability to repair genetic damage, changes in enzyme activity, reduced cell proliferation and increased generation time. Experiments investigating growth rates in mammalian cells have shown an increase in cell density at confluence. Human cells were less efficient in scavenging reactive oxygen species, possibly due to an impaired activity of antioxidant enzymes and ultimately demonstrated an increase in radiation induced mutations. At the organism level, fruit flies, commonly used to investigate human gene function, were grown deep underground. After only one generation, these living organisms demonstrated a significant increase in median life span and a 30% reduction in fertility for several generations. There is thus scope for investigations into the beneficial and harmful effects of the deep-underground environment on humans which could provide insight into biological processes that drive mutation and evolution in living organisms.
This review of existing literature and ongoing research aims to outline the types of experiments conducted at the most reputable DULs globally to consider how the infrastructure has benefitted research, to contemplate opportunities for novel interdisciplinary research and to present an outlook on the goals and possibilities at PAUL.

Speaker: Tarryn Bailey

PAULTBailey.pdf

11:50 Test of long term viability of cryogenized stem cells in Deep Underground Laboratory

Stem cells have the capacity to ensure the renewal of tissues and organs. They could be used in the future for a wide range of therapeutic purposes and are preserved at liquid nitrogen temperature to prevent any chemical or biological activity up to several decades before their use. Deep Underground Laboratory could have a role to play to ensure long term viability of cryogenized stem cell. Indeed, these frozen cells accumulate damages coming from natural radiations including terrestrials cosmic-rays, potentially inducing DNA double-strand breaks (DSBs). Such DNA damage in stem cells could lead to either mortality of the cells upon thawing or a mutation diminishing the therapeutic potential of the treatment. Many studies show how stem cells react to different levels of radiation; the effect of terrestrial cosmic rays being key, it is thus also important to investigate the effect of the natural radiation on the cryopreserved stem cell behavior over time. A study lead by physicists from CNRS-IN2P3 (France), physician and biologist from Pasteur Institute (France) showed that the cryostored stem cells totally shielded from cosmic rays had less DSBs upon long-term storage and in-vivo tests have been performed. The results of the interdisciplinary collaboration between physics, medicine and biology have been published in Cell Transplantation Journal of regenerative medicine (1). This could have important implications on the long-term cryostorage strategy and quality control of different cell banks. Various studies are in progress with differents types of biological materials.

(1)Cryopreserved Stem Cells Incur Damages Due To Terrestrial Cosmic Rays
Impairing Their Integrity Upon Long-Term Storage
P. Rocheteau, G. Warot, M. Chapellier, M. Zampaolo,
F. Chretien, and F. Piquemal (corresponding author)
Cell Transplantation
Volume 31: 1–15 (2022)

Speaker: Fabrice Piquemal (CNRS)

Fabrice-cells-preservation-size.pdf

12:13 Biological research at the deep underground low radiation background laboratory (DULB-4900) of Baksan Neutrino Observatory

Deep underground laboratories at physical research centers possess an outstanding potential for hosting interdisciplinary experiments, which became more systematic since 2010s, and studies are focused on tasks of biophysics, radiobiology, astrobiology, microbiology and medicine. Molecular genetics group of DLNP JINR initiated cooperative studies at Baksan Neutrino Observatory (BNO INR RAS) in the deep underground low radiation background laboratory (DULB-4900), located in the Elbrus region (North Caucasus, Russia) beneath (~2.5 km) the peak of Andyrchy mountain. First biological experiments were performed in 2019 and aimed to validate for the first time the response of complex model organisms to the low background radiation by modern genomics techniques (transciptomics). The experiment was successfully completed and contributed to the understanding of such important environmental factors as natural background radiation. Further genomic experiments of our group deal with biological impact of specific components of natural background radiation and deep underground exposome. To sum up, our works approved the uniqueness of DULB-4900 laboratory for biological research and importance of cooperation between deep underground facilities around the world to obtain more solid knowledge on biophysical phenomena. All these aspects will be discussed in the report.

Speaker: Mr Mikhail Zarubin (Joint Institute for Nuclear Research)

Zarubin_RSA_presentation_ready.pdf

12:36 The ultra-­‐low background laboratory STELLA (SubTErranean Low Level Assay) in the Laboratori Nazionali del Gran Sasso (Italy) underground laboratories

The underground laboratories of the Laboratori Nazionali del Gran Sasso of the National Institute of Nuclear Physics (LNGS-­‐INFN) are hosting the ultra-­‐low background laboratory STELLA.
see dtails in the pdf file.

Speaker: Matthias Laubenstein (LNGS-INFN)

PAUL_2024_STELLA_Laubenstein_final.pdf

13:00 → 14:00 Lunch

14:00 → 15:19 Muon flux and Radiation

Convener: Marcello Messina (LNGS-INFN)

14:00 From cosmos to the center of the earth : muography and applications

Speaker: Jacques Marteau (IP2I and Université de Lyon, France)

muography_JMarteau_Mont-Terri_to_PAUL_SSP_January2024.pdf

14:28 Modelling the Muon Flux in the Huguenot Tunnel

The Southern hemisphere offers a wonderful opportunity for scientists to explore unique
initiatives offered by a low-level radiation facility. Establishing a deep underground physics
laboratory to study, amongst others, double beta decay, geo-neutrinos, reactor neutrinos and
dark matter has been discussed for more than a decade within the austral African physicists’
community. The Paarl-African Underground Laboratory (PAUL) is foreseen as an open
international laboratory, a unique opportunity for Africa, devoted to the development of
competitive science in the region. It has the advantage that the location, the Huguenot tunnel,
exists already and the geology and the environment of the site is appropriate for an
experimental facility. A report of the most recent developments in the modelling of muon flux
and muon measurements which are required for the establishment of the PAUL and the
envisaged research programs is presented.
Background radiation levels due to cosmic rays have always been a thorn in the side of low￾level radiation facilities. To counteract this background radiation, these facilities have moved
underground into a tunnel or mine so that the overburden will act as a shield to attenuate and
stop the high energy cosmic rays. In this instance there will be looked into developing an
underground physics facility called PAUL (Paarl Africa Underground Lab) in the Huguenot
Tunnel connecting Paarl and Worcester in South Africa. This paper will address the
attenuation and propagation of cosmic ray muons through the mountain to get an idea as to
how the background muon noise this facility must take into account. To achieve this a Monte
Carlo Code, GEANT4 will be used to simulate the scenario. The results found in this paper
were in reasonable agreement with those in literature and previous studies done on the topic.

Speakers: Mr Cornel du Villiers (Stellenbosch University), Stephan Jonker

Jonker-Projek Presentation Final_Jonker.pdf

14:46 Development of a mobile LaBr3:Ce detector unit for in situ radionuclide analysis at TENORM contamination sites

Techniques and methods for the measurement and characterisation of naturally occurring radionuclide materials (NORM) and technologically enhanced naturally occurring radioactive materials (TENORM) in the environment are readily available. Most of these methods rely on laboratory-based HPGe or NaI detection systems. There is a need to measure and characterise radionuclides in different natural environments ranging from easily accessible to more harsh or inhospitable areas. This led to the development of a mobile gamma-ray detection unit (MRDU) in the form of a backpack that makes the measurement of radionuclides in more harsh environments possible, even on foot. An additional requirement of the mobile unit is the generation of high-quality spectral data. The MRDU was equipped with a LaBr3:Ce detector because of its superior peak resolution and photon detection efficiencies compared to the more conventional, and readily available NaI detectors. The MRDU is equipped with a USB GPS system that allows the accumulation of real-time spectral data combined with a spatial distribution of the radionuclides of interest. Experimental data have been collected at several different sites using the MRDU indicating its utility to do rapid and reliable measurements of primordial radionuclides (NORM and TENORM) as well as anthropogenic radionuclides in different terrestrial environments. It remains to approximate the state of decay disequilibrium at the sites. The MRDU results will be verified using HPGe gamma-ray spectrometry and chemical analysis of grab samples taken at the various measuring sites. This will enable predictions of the future fate and transport of radionuclides, and therefore radiation contamination in terrestrial environments. Results obtained during these experimental measurements will be presented and discussed, and conclusions drawn during the discussion.

Speaker: Ferdinand van Niekerk (iThemba LABS)

Ferdie_PAUL Symposium Presentation slides.pdf

15:04 Portable African Neutron-Gamma Laboratory for Innovative Nuclear Science

The Portable African Neutron-Gamma Laboratory for Innovative Nuclear Science (PANGoLINS) project aims to further investigate measurements of neutrons which forms an important component part on site or in transit and the detection of both fissile material for the use in decarbonised energy sources or disposal thereof. iThemba LABS has pioneered a mobile gamma-ray detection unit which allows a user to operate in the field and chart the location, strength and energy of gamma radiation. This project allows not only for investigation of neutrons but anticipates the value add on other features that are outdated i.e. battery pack and reducing current, temperature monitoring that impacts data and overall analysis. Benefits of the outcome of this project includes economic impact, contribution to GDP etc., increased highly skilled capacity and knowledge base and increased capabilities for technically innovation and social impact including improvement in quality of life, poverty alleviation and the potential impact in lowering barriers to entry for other South African technology innovations.
An overview of the project, it progress and potential outcomes will be presented.

Speaker: Peter Michael Jones (iThemba LABS, National Research Foundation (ZA))

SSP2024_Jones.pdf

15:40 → 16:31 Neutron flux and Radiochemistry

Convener: Fabrice Piquemal (CNRS)

15:40 Low neutron flux detectors for underground laboratories

Ambient neutrons are one of the sources of background events for
experiments studying neutrinos and searching for dark matter. This is
due to the penetrating ability of neutrons, and the fact that when
neutrons enter the detector, they can cause signals indistinguishable
from the searched ones. Preliminary measurements of neutron fluxes at
experimental sites make it possible to select the optimal shield
configuration for protecting the detectors and make assumptions about
the contribution of the neutron background to the expected result. Thus
monitoring changes in neutron flux during basic measurements is the
basis for correct interpretation of experimental results. The report
will describe detectors and methods for measuring extremely low neutron
fluxes at the level of $10^{-9}$ neutrons per cm$^{2}$/s, used and developed at DLNP JINR.

Speaker: Daniya Zinatulina (Joint Institute for Nuclear Research)

5-PAUL_2024_ZinatulinaDR.pdf

15:58 Measuring the neutron fields within Paarl Africa Underground Laboratory

Construction of the Paarl Africa Underground Laboratory (PAUL) offers an opportunity for the community of austral African physicists to develop an international laboratory devoted to underground physics in the southern hemisphere. One of the main background components within PAUL will be energetic neutrons produced by cosmic rays, and neutron fluence rates ranging between 10-6 n/cm2/s to 10-5 n/cm2/s can be expected [1,2].
We discuss approaches for measuring the background neutron fields within PAUL, which will be supported by the existing fast neutron beam facilities at the University of Cape Town and iThemba LABS.

[1] K. Eitel and the EDELWEISS collaboration. Measurements of neutron fluxes in the LSM underground laboratory. J. Phys.: Conf. Ser. 375 (2012) 012016. doi:10.1088/1742-6596/375/1/012016

[2] Y.S. Yoon, J. Kim and H. Park. Neutron background measurement for rare event search experiments in the YangYang underground laboratory. Astropart. Phys. 126 (2021) 102533. https://doi.org/10.1016/j.astropartphys.2020.102533

Speaker: Zina Ndabeni (University of Cape Town and iThemba LABS)

SSP2024-ZinaNdabeni_17Jan2023.pdf

16:16 Radiochemistry for underground physics

Currently, one of the main tools for new physics searching is the experiments at the underground laboratories, where the background is suppressed. When cosmic rays are suppressed, the main source of background is radioactive contamination of materials, facilities and measured samples. Modern level of underground experiments requires transition from mBq/kg to μBq/kg of impurities levels. Achieving such levels from a preparative and analytical point of view is a complex task that requires the use of advanced achievements in radiochemistry, analytics (ICP-MS, neutron activation analysis), and experience in gamma spectrometry. In the talk the cutting-edge approaches applied at DLNP JINR for achievement of requested levels of radiopurity by radiochemical, analytical and other methods will be reported.

Speaker: Ayagoz Baimukhanova (JINR, INP KZ)

7-Baimukhanova @PAUL_2024.pdf

16:31 → 17:01 Tea or Cofee break

17:01 → 18:17 On PAUL

Convener: Fabrice Piquemal (CNRS)

17:01 Background radiation measurements for underground experiments performed at UWC and measurements for PAUL

The physics department at the University of the Western Cape is involved in measurements to limit the background in the planned nEXO experiment. This experiment will look for neutrinoless double beta decay from $^{136}$Xe in SNOLAB in Canada.

The background issues involved in underground laboratories namely the natural activity from the surrounding rocks and the radon exhalation from the materials used in underground experiments, will be described in this contribution. Detector systems used for the specialised radon exhalation measurements and the set-ups used at SNOLAB will be briefly described and some results shown.

Some measurements of radon and other parameters in PAUL will also be presented.

Speakers: Robert Lindsay (University of the Western Cape), Lumkile Msebi (University of the Western Cape), Enkosi Ngwadla (University of the Western Cape)

Paul_Lindsay2.pdf

17:24 Cleanroom and monitoring in underground laboratories (Remote talk)

Underground laboratories provide the low radioactive background environment necessary to cutting edge experiments in particle and astrparticle physics and other disciplines such as geology and biology, that can profit of their unique characteristics and reduced muon flux. The laboratories requires continuous monitoring of environmental parameters, spanning from temperature, humidity to radon content and particulate concentration and fall-out which could affect the installation and operations of experiments. I will briefly review the monitoring needed at underground laboratories with a special attention to cleanroom environment along with cleanliness protocol and logistics.

Speaker: Silvia Scorza (LPSC-Grenoble, CNRS -UGA, France)

20240117_SPP_Scorza.pdf

17:47 PAUL from the ANDES perspective (Remote talk)

I'll discuss my personal perspective on PAUL based on the last 12 years process of the ANDES initiative. I will focus on a potential design for the underground laboratory, and on a specific science case: the search for daily modulation of potential dark matter signals.

Speaker: Xavier Bertou (CNEA/CONICET, Argentina)

2024-ANDES-PAUL.pdf

19:30 → 23:30 Banquet and Music

Thursday 18 January

09:00 → 10:30 Round table on PAUL strategy and future plans

Convener: Robert Lindsay (University of the Western Cape)

09:00 Round table on PAUL strategy and future plans

Chaired by: Rob Lindsay (UWC,ZA)
- Aldo Ianni (LNGS)
- Jodi Cooley (SNOLAB)
- Shaun Metzler Wyngaardt (SU,ZA)
- Fabrice Piquemal/Sébastien Incerti (CNRS-IN2P3, France)
- Sean Palling (Boulby UK)
- Rouven Essing (Stony Brook, US)
- Elizabetta Barberio (SUPL, Australia)
- Lero Lerothodo (UWC, ZA)

Speakers: Aldo Ianni (INFN LNGS), Elisabetta Barberio, Fabrice Piquemal (CNRS), Jodi Cooley, Lerothodi Leonard Leeuw (University of Johannesburg (ZA)), Prof. Rouven Essig (Stony Brook University), Sean Paling, Prof. Shaun Metzler Wyngaardt (Stellenbosch University)

10:30 → 11:00 Tea or Cofee break

11:00 → 11:25 Outlook and Opportunities

Conveners: Fairouz Malek (LPSC-Grenoble, CNRS and UGA, France), Richard Newman (Stellenbosch University, South Africa)

11:00 Short Summary

Speaker: Fairouz Malek (LPSC-Grenoble, CNRS -UGA, France and Stellenbosch University, SA)

11:10 The way forward for PAUL

Speaker: Richard Newman (Stellenbosch University, South Africa)

12:00 → 13:30 Lunch

14:00 → 18:00 Visit to the iThemba LABS cyclotron facility