Institute For Basic Science Research Articles

Design and commissioning of the ISOL beamline at the RAON facility

The Rare isotope Accelerator complex for ON-line experiment (RAON) located at the Daejeon site of the Institute for Basic Science (IBS) is the first Radioactive Isotope (RI) beam facility in Korea. The RAON facility employs an in-flight method using RI beams produced using an Isotope Separator On-Line (ISOL) method to explore unstable nuclei in uncharted regions. A high-power ISOL facility is critical for providing the required high-quality, intense RI beams. The design, construction, and installation of the ISOL system have been completed, and the beam transport line commissioning with stable isotope beams has been conducted. As a result, all requirements, such as the transmission and the mass-resolving power, for the beamlines were satisfied, and the beams from the Target Ion Source (TIS) were transported to the end of the ISOL beamline, which is the entrance to the superconducting linear accelerator system. The ISOL beamline is now ready for the transport of RI beams.

Improving Amplification Bandwidth by Combining Josephson Parametric Amplifiers for Active Axion Search Experiments at IBS/CAPP

The Center for Axion and Precision Physics Research at the Institute for Basic Science in Republic of Korea is home to multiple active axion search experiments using cavity haloscopes that operate within the frequency range of 1–6 GHz. The haloscopes convert axions to photons, resulting in an output power of about 10-24\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${^{-24}}$$\\end{document}–10-22\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${^{-22}}$$\\end{document} W. To detect such a small signal amidst noise, quantum-limited noise amplifiers and ultra-low-temperature environment (a few tenths of mK) are required for all critical readout components to minimize noise from all active and passive lossy components. Our primary objective is to achieve the highest possible scanning-frequency speed, which includes the time for maintenance and system calibration. This paper presents the development and operation of low-noise amplifiers for haloscope experiments targeting different frequency ranges and provides design, operational, and performance details of the amplifiers.

Construction of Yemilab

The Center for Underground Physics of the Institute for Basic Science (IBS) in Korea has been planning the construction of a deep underground laboratory since 2013 to search for extremely rare interactions such as dark matter and neutrinos. In September 2022, a new underground laboratory, Yemilab, was finally completed in Jeongseon, Gangwon Province, with a depth of 1,000 m and an exclusive experimental area spanning 3,000 m3. The tunnel is encased in limestone and accommodates 17 independent experimental spaces. Over 2 years, from 2023 to 2024, the Yangyang Underground Laboratory facilities will be relocated to Yemilab. Preparations are underway for the AMoRE-II, a neutrinoless double beta decay experiment, scheduled to begin in Q2 2024 at Yemilab. Additionally, Yemilab includes a cylindrical pit with a volume of approximately 6,300 m3, designed as a multipurpose laboratory for next-generation experiments involving neutrinos, dark matter, and related research. This article provides a focused overview of the construction and structure of Yemilab.

Overview of the Rare isotope Accelerator complex for ON-line experiments (RAON) project

A new rare-isotope beam (RIB) accelerator complex, RAON, is being constructed in the Institute for Basic Science (IBS) in Korea. RAON is equipped with both isotope separation online (ISOL) and in-flight fragmentation (IF) systems and ultimately combines them to provide more neutron-rich (than any single mode operation) ion beams to the users. However, due to the delay in developing high-energy superconducting cavities and cryomodules, it was decided to proceed with the RAON construction project in two phases. In the first phase, the low-energy accelerator system, ISOL, and all experimental setups will be completed by the end of 2022. In the second phase, the high-energy superconducting system will be completed by 2029 or later. In this contribution, the status of the accelerators, RIB production systems, and experimental instruments for RAON is summarized.

Performance of an ultra-pure NaI(Tl) detector produced by an indigenously-developed purification method and crystal growth for the COSINE-200 experiment

The COSINE-100 experiment has been operating with 106 kg of low-background NaI(Tl) detectors to test the results from the DAMA/LIBRA experiment, which claims to have observed dark matter. However, since the background of the NaI(Tl) crystals used in the COSINE-100 experiment is 2–3 times higher than that in the DAMA detectors, no conclusion regarding the claimed observation from the DAMA/LIBRA experiment could be reached. Therefore, we plan to upgrade the current COSINE-100 experiment to the next phase, COSINE-200, by using ultra-low background NaI(Tl) detectors. The basic principle was already proved with the commercially available Astro-grade NaI powder from Sigma-Aldrich (now Merck) company. However, we have developed a mass production process of ultra-pure NaI powder at the Center for Underground Physics (CUP) of the Institute for Basic Science (IBS), Korea, using the direct purification of the raw NaI powder. We plan to produce more than 1,000 kg of ultra-pure powder for the COSINE-200 experiment. With our crystal grower installed at CUP, we have successfully grown a low-background crystal using our purification technique for the NaI powder. We have assembled a low-background NaI(Tl) detector. In this article, we report the performance of this ultra-pure NaI(Tl) crystal detector produced at IBS, Korea.

Preface

This volume of the IOP Conference Series is dedicated to scientific contributions presented at the 20th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2021). In 2021, the motto guiding the scientific program was “AI Decoded: Towards Sustainable, Diverse, Performant and Effective Scientific Computing”. The workshop took place from November 29, 2021 to December 3, 2021 in Daejeon, Korea and virtually through teleconferencing.Due to the ubiquitous travel restrictions, most of the about 600 attendees participated virtually. ACAT is badged as a workshop, rather than a conference, because we believe discussions are a key ingredient. The significant fraction of virtual participation impacted this workshop atmosphere in 2021, despite the tremendous work that the Local Organizing Committee has invested in the successful workshop.To cater to virtual presentations, ACAT 2021 featured a highly focused scientific program with reduced session duration. Nonetheless, the scientific program was rich and varied, bringing together experts of all relevant fields from around the globe. It included fourteen invited presentations, both from High Energy and Nuclear Physics such as on “Normalizing Flows for LHC Theory” and “High Performance Analysis, Today and Tomorrow”, as well as from other fields such as the WHO.The parallel program consisted of three tracks, namely Computing Technology for Physics Research, Data Analysis – Algorithms and Tools, and Computations in Theoretical Physics: Techniques and Methods. These tracks featured 75 oral and 128 poster contributions. The posters were presented in a virtual environment that succeeded in engaging the audience.This was the last edition of ACAT that was unaffected by the Russian invasion of Ukraine and the subsequent statement of support from some Russian Federation Institutes.ACAT 2021 is co-organized by the Institute for Basic Science (IBS), the Korea Institute of Science and Technology Information (KISTI), and Soongsil University. IBS is supported by Grant No. IBS-R016-D1 and Soongsil University is supported by the National Research Foundation (NRF) of Korea Grant No. 2016R1D1A1B02012900. ACAT 2021 would like to thank for the support by the Asia Pacific Center for Theoretical Physics (APCTP), the Daejeon International Marketing Enterprise (DIME), the Korean Physical Society (KPS), Brookhaven National Laboratory, Fermi National Accelerator Laboratory, Thomas Jefferson National Accelerator Facility, and Micron Technology, Inc.List of Local Organizing Committee, Scientific Programming Committee, International Advisory Committee, Co-organizers, Sponsors are available in this Pdf.

Chemotherapy delivery time affects treatment outcomes of female patients with diffuse large B-cell lymphoma.

Chronotherapy is a drug intervention at specific times of the day to optimize efficacy and minimize adverse effects. Its value in hematologic malignancy remains to be explored, in particular in adult patients. We performed chronotherapeutic analysis using two cohorts of diffuse large B cell lymphoma (DLBCL) patients undergoing chemotherapy with a dichotomized schedule (morning or afternoon). The effect of a morning or afternoon schedule of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) on survival and drug tolerability were evaluated in a survival cohort (n = 210) and an adverse event cohort (n = 129), respectively. Analysis of ~14,000 healthy subjects was followed to identify the circadian variation in hematologic parameters. Both progression-free survival (PFS) and overall survival (OS) of female, but not male, patients were significantly shorter when patients received chemotherapy mostly in the morning (PFS hazard ratio [HR] 0.357; P = 0.033 and OS HR 0.141; P = 0.032). The dose intensity was reduced in female patients treated in the morning (cyclophosphamide 10%; P = 0.002, doxorubicin 8%; P = 0.002 and rituximab 7%; P = 0.003). This was mainly attributable to infection and neutropenic fever: female patients treated in the morning suffered from a higher incidence of infections (16.7% vs 2.4%) and febrile neutropenia (20.8% vs 9.8%) as compared to those treated in the afternoon. The sex-specific chronotherapeutic effects can be explained by the larger daily fluctuation of circulating leukocytes and neutrophils in females than in males. In female DLBCL patients, R-CHOP treatment in the afternoon can reduce the toxicity while it improves the efficacy and the survival outcome.

Science and technologies in targets for laser accelerators

<p indent="0mm">Laser plasma acceleration (also referred to as laser acceleration) employs ultra-strong electric fields generated when an ultra-intense laser pulse interacts with the plasma to accelerate charged particles. As a promising novel acceleration method, its acceleration gradient can be 10³–10⁶ times that of conventional accelerators. Laser accelerators based on the laser acceleration process can not only generate ultra-short pulse particle/photon beams for fundamental research, but also provide high-energy protons/heavy ions for tumor radiotherapy devices, benefiting people’s lives and health. Under the strong national investment around the world, basic and applied research related to laser accelerators has developed rapidly in recent years. Unlike conventional accelerators, which use macroscopic electromagnetic fields to accelerate particles in a vacuum, the laser acceleration process is realized by shooting targets with laser pulses. The scientific and technical problems related to the “target” are the core problems of the laser accelerator. In order to build an accelerator that can stably output high-energy particle beams, on the one hand, developing new target systems and deeply studying laser acceleration physics is highly necessary. On the other hand, overcoming a large number of key technical issues related to the preparation and characterization of targets and shooting is also very crucial. This paper gives an introduction to the key problems in the science and technologies for laser accelerators and highlights the progress in this field made by our team at the Institute of Heavy Ion Physics of Peking University. By exploiting nanotechnology and nanomaterials, we developed novel targets made of carbon nanotubes, which can serve as long-awaited perfect near-critical-density (NCD) targets. With such targets, we observed the laser focusing and pulse steepening in NCD plasmas for relativistic laser pulses for the first time. We also successfully achieved cascaded ion acceleration scheme by designing and building double-layer CNT targets, which solves the long-standing dilemma between the ionization and long-time acceleration of heavy ions acceleration. By collaborating with the Institute for Basic Sciences (IBS, Korea), we generated record-breaking <sc>580 MeV</sc> carbon ions and <sc>1.2 GeV</sc> Au ions in experiments. Recently, we numerically and experimentally studied how an ultra-intense femtosecond laser pulse interacts with a nanowire array target and eventually creates a high-energy-density plasma. The generation of soft-X-rays/EUV radiations and fusion neutrons from such a plasma were measured and studied in detail. Micro-channel targets are very interesting targets for us as well. We revealed how a laser pulse propagates through a micro-channel, peels off and accelerates electrons to GeV level, and produces corpus gamma rays with very small divergence angles. Experiments collaborating with the China Academy of Engineering Physics confirmed our prediction. Besides the above breakthroughs in acceleration sciences, we solved many key technical problems in laser ion accelerators. For example, we developed some mass-preparation methods for high-quality targets, including nanometer-thin diamond-like-carbon foils and metal foils, measured the target damage thresholds of a majority of existing targets in laser plasma experiments, figured out how to precisely locate transparent targets with high-precision. For non-stop running of the laser ion accelerators, we recently developed liquid sheets, which is highly promising to realize continuous beam delivery for weeks.

Impetuses and constraints in the policy formation process of the International Science and Business Belt in Korea

PurposeKorea’s Institute for Basic Science (IBS), the first research institute dedicated to basic science in Korea, started ten years ago as part of a science policy called the Science Belt. It is noteworthy that Korea, with a short history of basic science, established such a research institute exclusively for basic science within a short period of time and made it one of the representative institutions of basic science in Korea. This paper aims to uncover the impetuses and constraints surrounding the policy of Science Belt, centering on the IBS.Design/methodology/approachKingdon’s stream theory is used to clarify the factors that acted as impetuses or constraints for the Science Belt. For the analysis, in-depth interviews with the active policy participants were conducted in addition to the thorough literature review. The interviews enabled an in-depth understanding of the underlying factors for the Science Belt and the actual procedures of the policy decision.FindingsThis study found that the most powerful impetus in the Science Belt policymaking process was the President and a small group composed of a few scientists who played a leading role in the political stream. The constraint of the Science Belt was that the participation of scientist experts and governmental officials, the so-called invisible participants of Kingdon, was insignificant. In particular, there was no system in place to select policy alternatives for basic science through discussion between scientists and governmental officials.Research limitations/implicationsThe temporal scope of this study was limited to policy formation, that is, until the establishment of IBS. Therefore, future studies shall conduct a research on the implementation of the actual policy, IBS’s achievements and IBS’s impact of Korea’s basic science community.Originality/valueThis study applied both a theoretical framework and in-depth interviews along with the literature overview to understand a policymaking process from various angles.

From carbon superbases to superacids

Florian Mulks studied chemistry at Heidelberg University, where he obtained his doctorate with Stephen Hashmi in 2014. He spent his postdoctoral time in a variety of chemical disciplines with Shirin Faraji (University of Groningen), Eva Hevia (University of Strathclyde and University of Bern), Mu-Hyun Baik (Institute for Basic Science and Korea Advanced Institute of Science & Technology), and Guy Bertrand (University of California, San Diego). In early 2022, he founded a research group funded by the Alexander von Humboldt Foundation and Fonds der Chemischen Industrie at RWTH Aachen University to investigate molecular carbon chemistry and steric measurements.

Strong Formulations for Distributionally Robust Chance-Constrained Programs with Left-Hand Side Uncertainty Under Wasserstein Ambiguity

Distributionally robust chance-constrained programs (DR-CCPs) over Wasserstein ambiguity sets exhibit attractive out-of-sample performance and admit big-M–based mixed-integer programming reformulations with conic constraints. However, the resulting formulations often suffer from scalability issues as problem size increases. To address this shortcoming, we derive stronger formulations that scale well with respect to the problem size. Our focus is on ambiguity sets under the so-called left-hand side uncertainty, where the uncertain parameters affect the coefficients of the decision variables in the linear inequalities defining the safety sets. The interaction between the uncertain parameters and the variable coefficients in the safety set definition causes challenges in strengthening the original big-M formulations. By exploiting the connection between nominal chance-constrained programs and DR-CCP, we obtain strong formulations with significant enhancements. In particular, through this connection, we derive a linear number of valid inequalities, which can be immediately added to the formulations to obtain improved formulations in the original space of variables. In addition, we suggest a quantile-based strengthening procedure that allows us to reduce the big-M coefficients drastically. Furthermore, based on this procedure, we propose an exponential class of inequalities that can be separated efficiently within a branch-and-cut framework. The quantile-based strengthening procedure can be expensive. Therefore, for the special case of covering and packing type problems, we identify an efficient scheme to carry out this procedure. We demonstrate the computational efficacy of our proposed formulations on two classes of problems, namely stochastic portfolio optimization and resource planning. Funding: This work was supported by the DARPA Lagrange Program [Grant N660011824020], the National Science Foundation [Grant 1740707], the Office of Naval Research [Grant N00014-19-1-2321], and the Institute for Basic Science [Grants IBS-R029-C1 and IBS-R029-Y2].

Test Score Algorithms for Budgeted Stochastic Utility Maximization

Motivated by recent developments in designing algorithms based on individual item scores for solving utility maximization problems, we study the framework of using test scores, defined as a statistic of observed individual item performance data, for solving the budgeted stochastic utility maximization problem. We extend an existing scoring mechanism, namely, the replication test scores, to incorporate heterogeneous item costs as well as item values. We show that a natural greedy algorithm that selects items solely based on their replication test scores outputs solutions within a constant factor of the optimum for the class of functions satisfying an extended diminishing returns property. Our algorithms and approximation guarantees assume that test scores are noisy estimates of certain expected values with respect to marginal distributions of individual item values, thus making our algorithms practical and extending previous work that assumes noiseless estimates. Moreover, we show how our algorithm can be adapted to the setting in which items arrive in a streaming fashion while maintaining the same approximation guarantee. We present numerical results, using synthetic data and data sets from the Academia.StackExchange Q&amp;A forum, which show that our test score algorithm can achieve competitiveness and in some cases better performance than a benchmark algorithm that requires access to a value oracle to evaluate function values. Funding: This research was supported, in part, by the Institute for Basic Science [Grants IBS-R029-C1, IBS-R029-Y2].

Out-of-equilibrium chemical logic systems

Seoyeon Choi is currently a final-year integrated MS-PhD student at the Pohang University of Science and Technology (POSTECH) and the Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS) in South Korea, working under the guidance of Prof. Kimoon Kim. Her current research focuses on systems chemistry and supramolecular self-assemblies operating under out-of-equilibrium conditions. She aims to design functional supramolecular systems with emergent properties for mimicking natural non-equilibrium processes and developing artificial life-like systems.

Electromagnetic Investigation on a Sextupole HTS Magnet for RAON

The rare isotope accelerator complex for online experiments (RAON) is a heavy-ion accelerator equipped with an in-flight fragment separator (IF) system and isotope separation online technique in South Korea. Six quadrupole and a sextupole high-temperature superconducting (HTS) magnets are installed in the hot cell of the IF system, which is a high radiation region, to arrange the ion beams and correct the chromatic aberrations of the ion beams. The magnets are developed and installed for RAON at the Institute for Basic Science (IBS), South Korea. Superconducting magnet systems should be capable of a stable operation against high radiation heating and thermally and electromagnetically robust in the intense radioactive hot cell region. In this paper, we describe the design, fabrication, and evaluation of a sextupole HTS magnet. Electromagnetic designs are conducted considering the position of the HTS magnets and the angle of the yoke pole tip <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> The required design specifications are proposed as a part of RAON of IBS considering the following electromagnetic performance: 1) a magnetic field gradient of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \geq $</tex-math></inline-formula> 3.9 T/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , 2) magnetic field uniformity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ &lt; $</tex-math></inline-formula> 0.5%, 3) effective length of 450 ± 1 mm, and 4) operating temperature of ∼ 45 K.

Introducing our 2022 Early Career Advisory Board Members

Introducing our 2022 Early Career Advisory Board Members

First Results from an Axion Haloscope at CAPP around 10.7 μeV.

The Center for Axion and Precision Physics Research at the Institute for Basic Science is searching for axion dark matter using ultralow temperature microwave resonators. We report the exclusion of the axion mass range 10.7126-10.7186 μeV with near Kim-Shifman-Vainshtein-Zakharov (KSVZ) coupling sensitivity and the range 10.16-11.37 μeV with about 9 times larger coupling at 90%confidence level. This is the first axion search result in these ranges. It is also the first with a resonator physical temperature of less than 40mK.

A New Era

A New Era

Development of ultra-pure NaI(Tl) detectors for the COSINE-200 experiment

The annual modulation signal observed by the DAMA experiment is a long-standing question in the community of dark matter direct detection. This necessitates an independent verification of its existence using the same detection technique. The COSINE-100 experiment has been operating with 106 kg of low-background NaI(Tl) detectors providing interesting checks on the DAMA signal. However, due to higher backgrounds in the NaI(Tl) crystals used in COSINE-100 relative to those used for DAMA, it was difficult to reach final conclusions. Since the start of COSINE-100 data taking in 2016, we also have initiated a program to develop ultra-pure NaI(Tl) crystals for COSINE-200, the next phase of the experiment. The program includes efforts of raw powder purification, ultra-pure NaI(Tl) crystal growth, and detector assembly techniques. After extensive research and development of NaI(Tl) crystal growth, we have successfully grown a few small-size (0.61–0.78 kg) thallium-doped crystals with high radio-purity. A high light yield has been achieved by improvements of our detector assembly technique. Here we report the ultra-pure NaI(Tl) detector developments at the Institute for Basic Science, Korea. The technique developed here will be applied to the production of NaI(Tl) detectors for the COSINE-200 experiment.

A facility for mass production of ultra-pure NaI powder for the COSINE-200 experiment

COSINE-200 is the next phase of the ongoing COSINE-100 experiment. The main purpose of the experiment is the performance of an unambiguous verification of the annual modulation signals observed by the DAMA experiment. The success of the experiment critically depends on the production of a 200 kg array of ultra-pure NaI(Tl) crystal detectors that have lower backgrounds than the DAMA crystals. The purification of raw powder is the initial but important step toward the production of ultra-pure NaI(Tl) detectors. We have already demonstrated that fractional recrystallization from water solutions is an effective method for the removal of the problematic K and Pb elements. For the mass production of purified powder, a clean facility for the fractional recrystallization had been constructed at the Institute for Basic Science (IBS), Korea. Here, we report the design of the purification process, material recovery, and performance of the NaI powder purification facility.

Growth and development of pure Li2MoO4 crystals for rare event experiment at CUP

The Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) is searching for the neutrinoless double-beta decay (0νββ) of 100Mo in the molybdate crystals of the AMoRE experiment. The experiment requires pure scintillation crystals to minimize internal backgrounds that can affect the 0νββ signal. For the last few years, we have been growing and studying Li2MoO4 crystals in a clean-environment facility to minimize external contamination during the crystal growth. Before growing Li2100MoO4 crystal, we have studied Li2natMoO4 crystal growth by a conventional Czochralski (CZ) grower. We grew a few different kinds of Li2natMO4 crystals using different raw materials in a campaign to minimize impurities. We prepared the fused Al2O3 refractories for the growth of ingots. Purities of the grown crystals were measured with high purity germanium detectors and by inductively coupled plasma mass spectrometry. The results show that the Li2MoO4 crystal has purity levels suitable for rare-event experiments. In this study, we present the growth of Li2MoO4 crystals at CUP and their purities.