5th CERN Baltic Conference (CBC 2025)

14 Oct 2025, 09:00 → 16 Oct 2025, 19:00 Europe/Vilnius

Kaunas University of Technology, LITHUANIA

About the event

The CERN Baltic Conference (CBC) is an annual event hosted by a higher education or research institution from the CERN Baltic Group (CBG). Its aim is to connect and strengthen the scientific community in the Baltic states and other countries involved in CERN-related research.

The fifth edition of the CBC 2025 will be hosted by Kaunas University of Technology (KTU) in Kaunas, Lithuania.

Scope and scientific topics

The scope of CBC 2025 includes the presentation of the most recent results of the Baltic scientific community in CERN-related fields of research, as well as dedicated sessions for the discussion of national and regional level scientific policy, higher education and industry engagement topics.

The scientific topics include, but are not limited to:

• Particle physics: experiment
• Particle physics: theory
• Accelerator physics
• Accelerator and particle detector technologies
• Scientific and quantum computing

• Particle physics for medical applications

Objectives

The main objectives of CBC 2025  are to unite the global scientific community and share updates on the latest achievements of its members engaged in CERN-related research.

The aims of the event are:

• To connect and strengthen the scientific community in CERN-related research fields across the Baltic region and beyond.

• To stimulate the development of scientific research and higher education ecosystems in the Baltic states.

• To inform and engage policymakers across the region on the benefits of a strong research community and the requirements for its further growth.

• To involve various stakeholders, including higher education institutions and industry representatives, in shaping the scientific ecosystem in the Baltics.

The spirit of the event is rooted in the core principles of the CERN Baltic Group (CBG): transparency, honesty, sharing, and collaboration.

Target audience and participants

Researchers, engineers, and students, along with national and regional industry representatives and relevant policymakers are invited to participate.

Expert speakers from CERN and CBG member institutions will contribute to the scientific program of the conference.

Registration and important dates

• 30 April: Opening of the abstract submission and registration for the CERN Baltic Conference. To register for the event, please fill out the registration form.To submit an abstract, please complete the abstract submission form.

• 11 September: Deadline for abstract submission has been EXTENDED!

• 14 September: Deadline for notification of abstracts acceptance or rejection. 
• 30 September (by 17:00 CET): Final deadline for registration and payment of the registration fee. The abstract will be included in the electronic book of abstracts if the registration fee is paid.

Programme committee

Dr. Ramūnas Aleksiejūnas (VU, LT)

Dr. Erika Korobeinikova (LSMU, LT)

Dr. Brigita Abakevičienė (KTU, LT)

Dr. Gediminas Stankūnas (LEI, LT)

Dr. Saulius Mickevičius (VDU, LT)

Dr. Jonas Venius (NVI, LT)

Dr. Kārlis Dreimanis (RTU, LV)

Prof. Mārcis Auziņš (UL, LV)

Dr. Jevgenijs Proskurins (RSU, LV)

Dr. Jesus Alberto Cazares Montes (VIRAC, LV)

Dr. Sanita Kecko (DU, LV)

Prof. Fjodor Sergejev (TalTech, EE)

Prof. Veronika Zadin (UT, EE)

Prof. Mario Kadastik (NICPB, EE)

Local organising committee

Dr. Brigita Abakevičienė (Kaunas University of Technology)

Dr. Mantas Sriubas (Kaunas University of Technology)

Dr. Erika Korobeinikova (Lithuanian University of Health Sciences)

Dr. Gediminas Stankūnas (Lithuanian Energy Institute)

Giedrė Urkė (Kaunas University of Technology)

Mindaugas Ilickas (Kaunas University of Technology)

Augustinas Zinkus (Kaunas University of Technology)

Kristupa Šeškauskaitė (Kaunas University of Technology)

 

For further information you can contact the conference secretariat via cbg@ktu.lt.

The Conference is organized by the CERN Baltic Group, a collaboration of fourteen higher education and research institutions from the Baltic states, and is endorsed by CERN. 

General sponsors

   

Sponsors

 

Poster_CERN Baltic Conference.pdf

Tuesday 14 October

09:00 → 10:00 Registration

10:00 → 10:20 Conference Opening

Conveners: Dr Brigita Abakevičienė, Dr Karlis Dreimanis

10:00 Welcome by the Chair and Deputy Chair of the CERN Baltic Group

Speakers: Dr Brigita Abakevičienė (Kaunas University of Technology (LT)), Dr Karlis Dreimanis (Ryga Technical University | CERN)

10:10 Welcome by the Rector of Kaunas University of Technology

Speaker: Prof. Eugenijus Valatka

10:20 → 11:00 Policy

Convener: Dr Brigita Abakevičienė

10:20 Address from Lithuania: Mr. Artūras Malysis, Ministry of Education, Science and Sport of Lithuania

Speaker: Mr Artūras Malysis (Ministry of Education, Science and Sport of Lithuania)

10:28 Address from Latvia: Ms Liene Levada, Higher Education, Science and Innovation, Ministry of Education and Science of Latvia

Speaker: Ms Liene Levada

10:36 Address from the Baltic Assembly: Mr Saulius Čaplinskas, Vice Chair of the Health, Welfare and Family Committee of Lithuania

Speaker: Mr Saulius Čaplinskas

10:45 Welcome by the CERN Director for International Relations

Speaker: Charlotte Lindberg Warakaulle (CERN)

11:00 → 12:00 Baltic and National activities

Convener: Dr Brigita Abakevičienė

11:00 CERN - Latvia: State-of-play

The roots of scientific cooperation between Latvia and CERN stretch as far back the early 1990s, when researchers from the University of Latvia (UL) Institute of Solid-State Physics (ISSP) contributed to the scintillating crystal studies for the electromagnetic calorimeter of the Compact Muon Solenoid (CMS) experiment. In the following two decades sporadic yet significant cooperation continued with ISSP contributing to CERN’s Crystal Clear Collaboration, UL joining the ISOLDE collaboration and Riga Technical University signing an institutional cooperation agreement and joining the Future Circular Collider (FCC) project.
Since then, Latvia has substantially strengthened its scientific cooperation with the Laboratory, culminating in the accession to the status of an Associate Member State of CERN on august 2nd, 2021. Since then, work has been on-going to ensure a strong growth of the field of high-energy particle physics (HEP), as well as other relevant fields of research in the country, with the aim to attain to the status of a Full Member State of CERN as soon as possible.
In this contribution we discuss the current state of Latvia’s scientific and other collaboration with CERN, the recent milestones achieved, as well as the future plans.

Speaker: Dr Karlis Dreimanis (Riga Technical University (LV))

20251014_LV_SOP.pdf

20251014_LV_SOP.pptx

LATVIA - CERN: state-of-play

11:20 CERN - Estonia: State-of-play

Speaker: Prof. Fjodor Sergejev (Tallinn University of Technology (EE))

11.20_Fjodor.pdf

11.20_Fjodor.pptx

CERN-Estonia: State-of-play

11:40 CERN - Lithuania: State-of-play

Lithuanian scientists began their collaboration with CERN in 1993 by joining research on radiation-induced defects in semiconductors and their impact on the performance of silicon detectors. Since then, the scope and scale of Lithuania’s participation in CERN experiments have grown substantially. This progress was significantly facilitated, first, by Lithuania becoming an Associate Member State of CERN in 2018, and second, by the establishment of the Lithuanian Consortium for Particle Physics (LCPP) in 2022, tasked with coordinating efforts and allocating resources.
Today, as Lithuania enters the second half of its second five-year membership term, Lithuanian scientists contribute to data analysis and upgrade tasks of the LHC CMS and LHCb experiments. They are also active in DRD programs 1, 3, and 6, with plans to join DRD 5 and 7, and participate in nTOF, software development, and other activities. In Lithuania, considerable efforts are devoted to outreach, particularly targeting schoolteachers and pupils. Special attention is also given to developing ongoing and launching new medical research projects.
This presentation aims to provide a comprehensive overview of CERN-related activities in Lithuania—both from an internal perspective and as reflected in the most recent report of the International Advisory Board.

Speaker: Prof. Ramūnas Aleksiejūnas (Lithuanian Consortium for Particle Physics (LT))

RA_CBC_talk_2025-10.pdf

12:00 → 12:30 Advanced Particle Therapy Center for Baltic States: status report and next steps

Convener: Dr Brigita Abakevičienė

12:00 Advanced Particle Therapy Center for Baltic States: status report and next steps

Since 2022, with the active work of CERN Baltic Group in close collaboration with Next Ion Medical Machine Study (NIMMS) group of the European Organization for Nuclear Research (CERN), an initiative has been started for the development of an innovative particle therapy center in the Baltic States - “Advanced Particle Therapy center for the Baltic States” (APTCB). A dedicated working group was developed within the framework of CERN Baltic Group, which has evolved into “APTCB: Feasibility Study Strategy Group”. Proposed initiative would foster broad, multi-disciplinary research programme development, enable access to advanced cancer treatment modalities, contribute to breakthrough innovation development and cross-sectoral economic growth in the region, while strengthening integration of the Baltic States in a broader European scientific research network
Concept for the proposed facility was developed in Spring of 2022, followed by active engagement with political, scientific and medical community stakeholders, resulting in a workshop in 2023 “Particle therapy - future for the Baltic States? State-of-play, synergies and challenges”. Workshop outcomes, discussions with stakeholders and experience of similar projects has shown a need for a multi-disciplinary Feasibility Study as the next step of investigation for the future of the initiative.
This work aims:

• to present the status of the initiative, most recent stakeholder
  engagement activities and outline the developments of core
  technology.
• to present the development of Proposal for Feasibility
  Study Implementation Plan, focusing on the detailed
  multi-disciplinary working plan.
• to present brief overview of
  initial data collection study of radiotherapy practices in the Baltic
  States as relevant for the Feasibility Study development.

Main focus is given towards the future of the initiative – the Feasibility Study – outlining the motivation of the facility, proposed organizational structure of the investigation and detailing the working plan. In the preparation of the Feasibility Study, initial data collection study has been performed on radiotherapy practices in the Baltic States, with relevant finding presented in this work.
Looking forward, a detailed Feasibility Study investigation is an essential next step towards the development of such an ambitious infrastructure as APTCB due to multi-disciplinarity, high complexity and necessary costs, as well as relatively broad scope. Envisioned pathways for the launch of the Feasibility Study are presented in the conclusion.

Speakers: Erika Korobeinikova (Lithuanian University of Health Sciences (LT)), Kristaps Palskis (Riga Technical University (LV))

14_10_2025_CBC_APTCB_Status.pptx

Advanced Particle Therapy Center for Baltic States: status report and next steps

APTCB_Executive_summary_full.pdf

12:30 → 14:00 Lunch

14:00 → 14:30 Industry engagement: Doing Business with CERN: ILOs Report

Convener: Dr Karlis Dreimanis

14:00 Doing Business with CERN: ILO Report

Speakers: Ms Alise Pika-Ozola (Industrial Liaison Officer for Latvia), Ms Aušrinė Krištopaitytė (Innovation Agency Lithuania), Mr Raimondas Pučka (Innovation Agency Lithuania), Mr Robert Aare (Estonian Business and Innovation Agency)

Dosanjh-Overview of Particle Therapy-current status and future developments-14.10.2025.pdf

Dosanjh-Overview of Particle Therapy-current status and future developments-14.10.2025.pptx

14:30 → 15:20 Industry engagement: Industry

Convener: Dr Karlis Dreimanis

14:30 RIANA: Research Infrastructure Access in Nanoscience & Nanotechnology

The RIANA project, funded by Horizon Europe and coordinated by German Electron Synchrotron DESY, is designed to advance nanoscience and nanotechnology research. At its heart is the ARIE (Analytical Research Infrastructures in Europe) network, which consists of seven European networks of top-tier research infrastructures.
RIANA offers a single-entry point for researchers to access 69 advanced infrastructures. These facilities provide comprehensive support for nanofabrication, processing, characterization, analysis, and simulation. The project supports both curiosity-driven research with open-ended questions for long-term impact and challenge-driven research with targeted questions for short- to mid-term impact.
The project is geared toward both new and experienced users from academia and industry, helping them to develop promising ideas and advance them to higher TRL (Technology Readiness Levels). RIANA is flexible and can adapt to emerging scientific topics and needs by offering access to additional infrastructures both inside and outside of Europe. Drawing on four years of experience, the RIANA consortium will also develop a roadmap for the future of nanoscience and nanotechnology at European research infrastructures.
RIANA covers the complete process of nanoscience and nanotechnology research. This includes everything from the initial targeted simulation of nanomaterials and structures to their synthesis and manufacturing, and finally to expert-supported material characterization and analysis. RIANA provides a streamlined pathway to access some of Europe's most advanced research infrastructures (RIs).
Expert Support for Researchers. To ensure you get the most out of your time at the RIs, RIANA provides comprehensive Science Service support. A team of 21 junior scientists, supervised by senior scientists at each facility, is available to assist you with every stage of your research, including: selecting the right techniques from the RIANA network, running your experiments at the facilities, analyzing your data, preparing your reports and publications.
Innovation and Industry Collaboration. The Innovation Service is designed to help you unlock the potential for innovation that comes from accessing these RIs. It focuses on supporting industry-oriented access, with a special emphasis on small and medium-sized enterprises (SMEs). The goal is to help these companies: mature their technology, increase their Technology Readiness Level (TRL), scale up their production processes.

Speaker: Dr Andrius Žutautas (Kaunas University of Technology, Institute of Materials Science)

14.30_Andrius.pdf

14.30_Andrius.pptx

RIANA: Research Infrastructure Access in Nanoscience & Nanotechnology

14:50 AI: A Journey Through Time – Yesterday's Dreams, Today's Reality, Tomorrow's Horizon

Artificial Intelligence has transformed from a theoretical concept to an indispensable force shaping our world. This presentation will embark on a comprehensive journey through AI's rich history, exploring its foundational milestones and the visionaries who paved the way. We will then examine the current landscape of AI, highlighting its diverse applications and the profound impact it has on various industries, particularly its capacity to significantly boost productivity and drive innovation. Finally, we will delve into the practical implementation of AI within a real-world context, showcasing how Hostinger leverages cutting-edge AI technologies to enhance operations, improve user experience, and secure future growth.

Speaker: Dr Mantas Lukauskas (Hostinger, Kaunas University of Technology)

15:20 → 17:15 Particle therapy

Convener: Dr Erika Korobeinikova

15:20 Overview of Particle Therapy: Current Status and Future Developments

The battle against cancer remains a top priority for society, with an urgent need to develop therapies capable of targeting challenging tumours while preserving patient’s quality of life. Hadron Therapy (HT), which employs accelerated beams of protons, carbon ions, and other charged particles, represents a significant frontier in cancer treatment.

The potential of protons was first recognized by Wilson in 1946. The first patient was treated with proton therapy in 1954 in Berkley. Following this, research accelerators at numerous physics laboratories were adapted for radiotherapy with protons and, to a smaller extent, heavier particles. Advances in particle radiotherapy were rooted in the physics and radiobiology of using ion beams to target tumours with minimal damage to surrounding normal tissues.

The progression from laboratory to hospital was aided by translational pre-clinical radiobiology and early clinical research, which continued at the Lawrence Berkeley Laboratory in California and at the Svedberg Laboratory/University of Uppsala in Sweden, where the first patient in Europe was treated in 1956.

Carbon ion facilities were built and started to operate in the 1990s, like the Heavy-Ion Medical Accelerator (HIMAC) at the NIRS in Chiba, Japan in 1994 and the pilot heavy-ion therapy facility at the Gesellschaft Helmholtzzentrum für Schwerionenforschung (GSI) in Darmstadt, Germany (1993–1997). Based on the GSI experience, in 2005 the first European hadron therapy centre—the Heidelberg Ion Beam Therapy (HIT) centre—opened in Heidelberg, Germany, and HIT set up the world’s first isocentric gantry for carbon beams in 2007. A few years later, based on the PIMMS/TERA study at CERN, the Italian CNAO centre was built in Pavia and started treating patients in 2011. Similarly, the MedAustron synchrotron facility in Wiener Neustadt, Austria, completed in 2012, treated its first proton patient in 2013 and its first carbon patient in 2019.

Although there are around 110 proton and 15 carbon facilities, HT is a relatively young field. More research, as well as novel, cost-effective and compact accelerator technologies, are needed to make this treatment more widely available.

HT is gaining ground and, even after 70 years, the particle therapy field continues innovating for the benefit of patients globally. Developing technologies that are affordable and easy to use is key and would allow access to more patients. Advances in Boron Neutron Capture Therapy (BNCT), image-guided hadron beam delivery, clinical trials, immunotherapy, and FLASH therapy—an experimental ultrahigh-dose-rate approach—are examples of innovations that may expand access worldwide.

Speaker: Prof. Manjit Dosanjh (University of Oxford, United Kingdom)

Dosanjh-Overview of Particle Therapy-current status and future developments-14.10.2025.pdf

Dosanjh-Overview of Particle Therapy-current status and future developments-14.10.2025.pptx

Overview of Particle Therapy: Current Status and Future Developments

16:11 Towards the last millimetres in helium ion therapy: developing dedicated range verification methods

Introduction: Due to steep dose gradients of the Bragg peak, proton and ion beam therapy is more sensitive to treatment uncertainties compared to conventional radiotherapy. With overall range uncertainty of ~3 – 5%, ensuring robustness of treatment delivery reduces dose conformality – hindering full potential of these modalities.
Apart from conventional strategies, range verification methods could be used: Bragg peak localization via detection of secondary particles or dedicated anatomical imaging for relative stopping power evaluation. Such approaches could enable proper range assessment before and during treatment, delivered dose verification in-vivo and real-time identification of unexpected delivery inaccuracies - crucial in hypofractionation and novel modalities as FLASH therapy.
With helium ion therapy as promising future modality, studies on specifically adapted range verification methods are lacking, though would be beneficial for implementation in technical designs of dedicated delivery systems.

Aim of the Work: To investigate and quantitatively evaluate methods for range verification to ensure required precision and accuracy in high dose helium ion therapy by anatomical imaging or Bragg peak localization.

Methods: Presented work is based on Monte Carlo simulations performed in Geant4 (v. 11.0.1.), using computational resources of RTU High Performance Computing centre. Following range verification methods were quantitatively evaluated, considering technical design parameters of CERN NIMMS HeLICS synchrotron: high energy proton radiography, helium-3 ion radiography, mixed helium-deuteron beam radiography, positron emission tomography-based verification and prompt gamma photon signal enhancement by 18O contrast agent.
Several image quality metrics (spatial resolution, CNR, imaging dose, WEPL accuracy and others) were quantitatively evaluated for the radiography modalities. For Bragg peak localization methods, correlation with absorbed dose distribution, achievable range sensitivity and impact of primary beam intensity was assessed.

Results and Conclusions: For pre-treatment patient position verification, helium-3 ion radiography and 330 – 500 MeV proton radiography would enable sufficient image quality for full-body imaging.
Mixed helium-deuteron beams with fluence ratio 1:100 could be used for range monitoring, while 1:10 – for 2-dimensional imaging during treatment delivery.
Direct Bragg peak localization in helium-4 ion therapy could be feasible via detection of unique fluorine-17 and fluorine-18 beta(+) decay patterns. Another approach could be prompt gamma photon signal enhancement by 18O contrast agent – increased emission yields and unique spectral lines for spectroscopic monitoring.

Speaker: Kristaps Palskis (Riga Technical University (LV))

CBC_2025_Range_verification_Palskis.pptx

Towards the last millimetres in helium ion therapy: developing dedicated range verification methods

16:53 Dose-per-Pulse and pH Dependence of Radical Yields under FLASH Irradiation

The FLASH effect is a promising advance in radiation therapy, reducing normal tissue toxicity without compromising tumor control when ionizing radiation is delivered at ultra-high dose rates (UHDRs) [1]. Preclinical studies support this benefit, yet mechanisms remain incompletely understood. Proposed explanations include radiolytic oxygen depletion, radical–radical recombination, and differences in tissue metabolism and microenvironment [2], with altered reactive oxygen species (ROS) generation considered central. To investigate how physicochemical processes differ between FLASH and conventional (CONV) irradiation, we quantified ROS production in aqueous solutions across irradiation conditions.
Experiments used a modified clinical Varian TrueBeam linear accelerator delivering 6 MeV electron beams [3]. FLASH irradiation was applied at mean dose rates of 12, 48, and 96 Gy/s with pulse doses of 2 or 4 Gy, whereas CONV irradiation was delivered at 0.15 Gy/s. Total doses up to 32 Gy were assessed. ROS formation was measured using the fluorescent probe dihydrorhodamine 123 (DHR123), and solution pH (6, 7, 8) varied to mimic physiological, tumor-like conditions.
ROS yields increased linearly with dose under both irradiation modes, but absolute ROS levels were consistently ~4-fold higher under CONV compared with FLASH across all doses. Within FLASH conditions, dose-per-pulse and mean dose rate influenced ROS production, with pulse dose having the stronger effect: increasing from 2 Gy to 4 Gy reduced ROS by ~30%, while raising the mean dose rate from 12 Gy/s to 96 Gy/s reduced ROS by 10–20%. Slope analysis indicated slower ROS formation at higher dose rates, consistent with enhanced radical–radical recombination at elevated instantaneous radical concentrations.
ROS generation under FLASH also depended on pH: yields decreased with increasing pH, highest at pH 6 and lowest at pH 8, whereas CONV irradiation showed no pH dependence, consistent with hydrogen peroxide stability [4].
In conclusion, FLASH irradiation fundamentally alters radical chemistry compared to conventional dose rates. Suppression of ROS, modulation by pulse structure, and pH sensitivity support a mechanism in which UHDR irradiation promotes radical recombination, protecting normal tissues while maintaining tumor damage. These findings strengthen the mechanistic basis of the FLASH effect and highlight the importance of microenvironmental factors such as pH in optimizing FLASH radiotherapy protocols [1–4].

Funding: Research Council of Lithuania (LMTLT), agreement No. S-MIP-24-134.

References
1. Favaudon V. Sci Transl Med, 2014;6(245)
2. Esplen N. Phys Med Biol, 2020;65(23)
3. Šlėktaitė-Kišonė A. Med Phys Balt States 16, 2023, p. 92–95
4. Roth O., LaVerne J. A. J Phys Chem A, 2011;115:700–708

Speaker: Mr Mindaugas Džiugelis (National Cancer Center)

16.53_Mindaugas.pdf

16.53_Mindaugas.pptx

17:15 → 18:45 Poster session: Poster session + Refreshments

Conveners: Arnoldas Solovjovas (Vilnius University (LT)), Benjaminas Togobickij (Lithuanian Energy Institute (LT)), Dairis Rihards Irbe (Riga Technical University (LV)), Eliza Holvoet (Vilnius University (LT)), Erika Rajackaitė (Kaunas University of Technology (LT)), Ilze Baumgarte (Riga Technical University (LV)), Jevgenij Pavlov (Vilnius University (LT)), Kestutis Zilinskas (Vilnius University (LT)), Kristupa Šeškauskaitė (Kaunas University of Technology (LT)), Laimonas Deveikis (Vilnius University (LT)), Meda Paulaviciute (Vilnius University (LT)), Mikas Iršėnas (Vilnius University (LT)), Neilas Beniusis (Vilnius University (LT)), Rimantas Naina (Vilnius University (LT)), Rostislavs Rostovskis (University of Latvia (LV)), Simona Breidokaitė (Lithuanian Energy Institute (LT)), Sophia Pennuttis (Vilnius University (LT)), Tomas Čeponis (Vilnius University (LT)), Vytautas Rumbauskas (Vilnius University (LT))

Wednesday 15 October

09:30 → 12:08 Particle Physics Theory

Convener: Dr Torben Lange

09:30 Searching for the Clue to our Existence

When antimatter and matter annihilated themselves shortly after the Big Bang, a tiny amount of matter was leftover. This is what all planets, stars and galaxies of the known universe are made of. While processes are known for decades that violate the symmetry between matter and antimatter, they are by far insufficient to explain what happened in the early universe. The talk will discuss studies of antimatter from cosmic sources to the world’s largest accelerator. A wide range of ongoing and planned experiments in the coming one to two decades have the potential of identifying signals of particles beyond the current Standard Model of particles physics. These may point to new sources of matter-antimatter asymmetries and thus ultimately to a clue to our existence.

Speaker: Prof. Marco Gersabeck (University of Freiburg, Germany)

Lecture slides_Marco Gersabeck.pdf

Searching for the Clue to our Existence

10:21 Renormalization of the quark mixing matrix and W boson decay into quarks

Renormalization of mixing matrices is still a rather open question in particle physics. Previously, we have devised a renormalization scheme which satisfies all the mixing renormalization requirements (UV finiteness, gauge-independence, etc.) trivially. In this presentation we showcase our renormalization scheme of mixing matrices by computing the hadronic $W$ decay widths in the Standard model with a trivial CKM mixing matrix counterterm. We also present preliminary numerical results comparing our scheme with other schemes found in the literature.

Speaker: Mr Simonas Draukšas (Vilnius University (LT))

CBC5_SDrauksas.pdf

Renormalization of the quark mixing matrix and W boson decay into quarks

10:42 QCD and multiplicity fluctuations

An improved perturbative QCD approach is developed that addresses
the pattern of hadron multiplicity fluctuations in quark and gluon jets produced in e+e- annihilation, LHC and elsewhere.
Two seemingly unrelated puzzling phenomena recently observed by ATLAS and CMS experiments may have a common origin (RSE, the rattlesnake effect).

Speaker: Prof. Yuri Dokshitzer

QCD and multiplicity fluctuations

Slides_Yuri Dokshitzer.pdf

11:03 Path integral dualities: Maxwell, Proca, Kalb-Ramond and more

A careful study of the physical content of field dynamics reveals that different field content might actually correspond to the same physical system. This is the basic case for dualities between different theories. Some recent results are reviewed, with the emphasis that this situation corresponds to simple path integral identities. This holds true for the S-dual in Maxwell-Chern-Simons theory, just as it holds true in (vacuum) Proca-Kalb-Ramond: in turn, any modification, such as self-interactions, can easily spoil this correspondence. But to build new physics, exactly this kind of spoiling is required. Some cases of degenerate potentials as permitting multiple constitutive law phases are considered, but it can be shown that such extensions do not appear viable for internal gauge theory alone. Nevertheless, some further adventurous exploration of such potentials remains well-motivated.

Speaker: Priidik Gallagher (University of Tartu)

Gallagher_Kaunas2025.pdf

Path integral dualities: Maxwell, Proca, Kalb-Ramond and more

11:24 Decay rates of neutrinos in the Grimus-Neufeld model

We present the decayrates of neutrinos in the Grimus-Neufeld model as a background to the question, in which sense the model is still consistent with Cosmological observations.

Speaker: Thomas Gajdosik (Vilnius University (LT))

CBC_2025_tg.pdf

Decay rates of neutrinos in the Grimus-Neufeld mode

11:45 Baryonic Bound States in the Non-Local NJL Model

Baryons, as the fundamental building blocks of nuclear matter, are less investigated than mesons, as they have a more complex substructure. They are classified according to the quark model, which explains their properties based on quark content and interactions. Baryons are composite subatomic particles made up of three quarks. The Faddeev approach is a mathematical model to describe the baryons. In this model, a baryon is treated as a bound state of a diquark and a third (so-called spectator) quark. This approximation reduces the complexity of solving the three-body problem by considering effective interactions between a diquark and a single quark.
The primary aim of this talk is to describe what the Faddeev approach is, how to make use of and solve the Bethe--Salpeter equations for the baryons in the Faddeev approach, and finally, how we aim to make use of this approach in our project.

Speaker: Arpan Chatterjee

11.45_Arpan.pdf

Baryonic Bound States in the Non-Local NJL Model

12:08 → 13:00 Lunch

13:00 → 14:30 Particle Physics Experimental I

Convener: Dr Tomas Gajdosik

13:00 Overview of the LHCb Experiment at CERN and Recent Results

The LHCb (Large Hadron Collider beauty) experiment at CERN is a dedicated detector designed to study the decays of heavy-flavor hadrons containing bottom and charm quarks. Operating at the Large Hadron Collider, LHCb provides unique sensitivity to processes involving flavor physics, CP violation, and rare decays, enabling precise tests of the Standard Model and searches for physics beyond it. Over the past years, the experiment has delivered a wide range of significant results, including improved measurements of CKM matrix parameters, observations of rare decays mediated by flavor-changing neutral currents, studies of exotic hadrons such as tetraquarks and pentaquarks, and precision tests of lepton flavor universality. These achievements have been made possible through the combination of a highly specialized forward spectrometer, advanced trigger systems, and large datasets collected during Runs 1 and 2 of the LHC. With the ongoing Run 3 data-taking period and a major detector upgrade, LHCb is entering a new phase of precision measurements and enhanced discovery potential, paving the way for deeper insights into the fundamental structure of matter.

Speaker: Dr Mindaugas Sarpis (Vilnius University (LT))

Overview of the LHCb Experiment at CERN and Recent Results

13:22 Measurement of boosted top quark mass at CMS experiment

As the heaviest particle in the Standar Model (SM) and due to its large Yukawa coupling, the top quark plays a crucial role in the electroweak sector of the SM. Beyond direct measurements of the top quark mass, which depend on precise modelling of the parton shower and hadronization process, and cross-section measurements, sensitive to various sources of uncertainty, an alternative approach can be pursued: determining the top quark mass from the jet mass in Lorentz-boosted top quark events. At high energies, the well-known decay products merge into a single large-radius jet.

In the lepton+jets channel of $t\overline{t}$ production, the leptonic $W$ boson decay provides a clean signature while suppressing the backgrounds from events with light-flavour and gluon jets. At the same time, the hadronic decay enables the full reconstruction of the top quark within a single large-radius jet. To improve this reconstruction, we employ the XCone reclustering algorithm, which ensures the desired number of jets and allows us to separate the two top quark decays of the $t\overline{t}$ system into different "fat-jets".

We will present the progress and current status of this study, the main goal of which is to determine the top quark mass at the detector level by analysing Run3 data, exploiting the jet mass observable, and applying the XCone algorithm during the reclustering phase.

Speaker: Conrado Munoz Diaz (Riga Technical University (LV))

Measurement of boosted top quark mass at CMS experiment

Measurement of boosted top quark mass at CMS experiment CBC25_v5.pdf

13:44 Study of the b-fragmentation function and the dead cone effect in bottom quark jets from $t\bar{t}$ decays in proton–proton collisions at $\sqrt{s} = 13.6$ TeV at the CMS experiment

We present a measurement of the substructure of bottom quark jets originating from $t\bar{t}$ decays in proton--proton collisions at the CMS experiment. In particular, we study the $b$-fragmentation function and the dead cone effect using dilepton $t\bar{t}$ events from Run 3 data collected at $\sqrt{s}=13.6$ TeV. The $b$-fragmentation function, which describes how a $b$ quark fragments into a bottom hadron, is essential for precision measurements of the Higgs boson and the top quark, for studies involving heavy flavour, and for searches for new physics. It also plays a significant role in the reconstruction and identification of $b$-jets.

These analyses exploit jets reconstructed with the anti-$k_{t}$ algorithm and apply a ParticleNet neural network, trained with the Weaver framework, to Particle Flow candidates inside $b$-jets. This approach enables the reconstruction of the charged $B$ hadron and its momentum within the jet. The $b$-fragmentation function is then extracted as the ratio of the transverse momentum of the reconstructed $B$ hadron to that of the associated $b$-jet.

Jet substructure observables studied are also sensitive to the dead cone effect, a fundamental prediction of QCD whereby gluon radiation is suppressed within a characteristic angular region around a heavy quark. To probe this phenomenon, we employ iterative declustering techniques that trace the branching history of $b$-jets and measure the angular distribution of emissions relative to the $b$ quark.

The results provide input for the tuning of fragmentation and hadronization models, benefiting a wide range of CMS measurements involving heavy-flavour jets. In addition, sensitivity to the dead cone effect complements related CMS studies and offers important prospects for precision tests of QCD at the High-Luminosity LHC.

Speaker: Dimitrios Sidiropoulos Kontos (Riga Technical University (LV))

Presentation_CERN_Baltic_Conference_2025.pdf

Presentation_CERN_Baltic_Conference_2025.pptx

Study of the b-fragmentation function and the dead cone effect in bottom quark jets from decays in proton–proton collisions at TeV at the CMS experiment

14:06 Di-Higgs searches with the CMS Experiment

Since the discovery of the Higgs boson in 2012 by the CMS and ATLAS collaborations, many properties of this once elusive particle and key component of the Standard Model of particle physics (SM) have since been measured. One of the remaining properties still to check is the self coupling of the Higgs boson deeply linked to the Higgs mechanism and the underlying Higgs potential.
Double Higgs (HH) searches provide one of the most direct ways to prove this coupling while simultaneously offering us a chance to look for a multitude of beyond Standard Model signals when studying the same signatures.
With sensitivity to the SM coming within reach, HH has become one of the hot topics of the high energy physics community.
Our Institute and the Baltics as a whole have been very active on this front, and this talk is going to highlight these contributions, the overall state of the HH field as well as the future ahead.

Speaker: Torben Lange (National Institute of Chemical Physics and Biophysics (EE))

CBC2025_TorbenLange.pdf

Di-Higgs searches with the CMS Experiment

14:30 → 14:50 Coffee break

14:50 → 16:45 Particle Physics Experiment II

Convener: Dr Andrius Juodagalvis

14:50 What’s Next in Particle Physics? – Experimental Perspective

Over the last five decades, many outstanding questions in particle physics have been answered, leading to the Standard Model (SM) and its spectacular confirmation with the discovery of the Higgs boson in 2012, which would supply the heart to this theory. Now the hunt is for a deeper theory of reality. To answer this question, Europe, Japan, the US and China have proposed plans for building new particle colliders focused on studying the Higgs boson. Higgs’ legacy will be the experimental particle physics programme of the 21st century. The open questions of today are just as profound as they were a century ago. However, there appears to be many more of them. Recent discoveries of the Higgs boson and Gravitational waves required increasingly sophisticated instrumentation and have created an exceptionally positive environment in society. Thus, we have a “virtuous cycle” which must remain strong and un-broken – laws of nature enable novel detector and accelerator concepts, which in turn lead to a greater physics discoveries and better understanding of our Universe.

Particle physics is now entering a new era. As the scale and the cost of the frontier colliders increases, while the timescale for projects is becoming longer, fewer facilities can be realized. Moreover, several high-energy physics (HEP) laboratories are becoming multi-purpose ones. The pursuit of ever-higher energies will surely be one of the future directions of particle physics; the course will depend on whether one can continue to contain the cost of future colliders in the current worldwide environment. We must take a holistic view of particle physics - whether we find Beyond Standard Model physics at the LHC or not - and select the path to follow in a prudent manner, while maintaining HEP accelerator laboratories and expertise in all regions. Our culture and management structure must evolve to confront these challenges.

Speaker: Prof. Maxim Titov (CEA Saclay, Irfu, France)

2025_10_KAUNAS_LITHUANIA_5th-CERN-BALTIC-CONFERENCE_WHAT's-NEXT-PARTICLE-PHYSICS_EXPERIMENTAL-PERSPECTIVE_15102025.pdf

2025_10_KAUNAS_LITHUANIA_5th-CERN-BALTIC-CONFERENCE_WHAT's-NEXT-PARTICLE-PHYSICS_EXPERIMENTAL-PERSPECTIVE_15102025.pptx

What’s Next in Particle Physics? – Experimental Perspective

15:41 Mighty-SciFi for LHCb Upgrade II

The LHCb Upgrade II (“Mighty” upgrade) pushes operation to an order-of-magnitude higher luminosity and demands a downstream tracker that withstands extreme hit rates, radiation, and continuous 40 MHz streaming while maintaining high efficiency and resolution. This challenge is met by the Mighty Tracker that adopts a hybrid layout: radiation-hard silicon pixels in the innermost, highest-occupancy region and large-area scintillating-fibre (SciFi) modules in the outer acceptance.
Building on Run-3 experience, the design prioritizes fine granularity, minimal material, and cold, stable operation tightly integrated with LHCb’s triggerless, real-time reconstruction. The outer Mighty-SciFi targets ≥99 % per-layer efficiency and ~70–100 µm single-hit precision with few-percent occupancies, robust 40 MHz performance, and radiation tolerance via cryogenic SiPMs in low-mass cold boxes, while scaling production and maintenance to tens of square metres at controlled cost. R&D is focused on faster, radiation-tolerant fibres to improve light yield, timing, and lifetime.
Materials diagnostics like confocal photoluminescence (PL) mapping and time-resolved PL spectroscopy—provide spatially resolved and temporal/spectral fingerprints of fibre quality and aging. Sub-100 µm confocal scans can expose dopant gradients, glue ingress, micro-scratches, and stress as intensity/lifetime contrasts, guiding QA to avoid local occupancy spikes and hit-residual biases. Time-resolved PL quantifies the scintillation decay τ and emission spectrum to validate SiPM PDE matching and to set front-end thresholds and clustering; shifts (slower τ, red-shift, broadening) flag self-absorption and quenching. These measurements close the loop between materials R&D and detector design, helping ensure the Mighty-SciFi meets HL-LHC timing/efficiency goals within mass and power budgets.

Speaker: Mr Augustas Vaitkevičius (Vilnius University (LT))

15.41_Vaitkevicius.pdf

Mighty-SciFi for LHCb Upgrade II

16:02 Status of the CMS MIP Timing Detector for the HL-LHC Upgrade

In preparation for the CMS Phase-2 upgrade targeting the High-Luminosity LHC (HL-LHC), significant progress has been made in the production and assembly of the MIP Timing Detector (MTD). The goal of this sub-system is to provide the CMS detector with precise 4D vertexing capability, enabling time resolution of $\sigma \sim 35\,\text{ps}$ for charged tracks, thus helping mitigate the effects of high pileup expected during HL-LHC operation. The MTD sub-detector is composed of the Barrel Timing Layer (BTL) and the Endcap Timing Layer (ETL). BTL is based on LYSO crystals read out with SiPMs, arranged in trays mounted on the BTL-Tracker Support Tube (BTST). ETL employs Low-Gain Avalanche Diodes (LGADs) and will be installed in the high-$\eta$ regions of CMS – placed on the face of the end-cap in front of the HGCAL sub-detector. Tray assembly for the BTL is progressing well across all assembly centers, with readout and cooling tests ongoing at CERN. For ETL, good progress has been achieved in testing hybrid bump-bonding of LGAD sensors, and test beams at the SPS are used to validate ETL modules. This contribution will provide an overview of the MTD sub-detector and highlight the latest advancements in its development.

Speaker: Dace Osite (Riga Technical University (LV))

Osite_Status_of_CMS_MTD.pdf

Status of the CMS MIP Timing Detector for the HL-LHC Upgrade

16:23 Prospects for Drell-Yan Precision Measurements with the CMS Phase-2 Detector at the HL-LHC

The High-Luminosity Large Hadron Collider (HL-LHC) will provide a dataset much larger than in previous runs, but it will also create more challenging conditions for detectors. To prepare for this, the CMS detector will undergo a Phase-2 upgrade, which will improve tracking, muon, and calorimeter performance.

The Drell-Yan production of lepton pairs is an important process for testing the Standard Model and understanding parton distribution functions. The precision of such measurements depends strongly on how well the detector can reconstruct leptons (electrons and muons). With the CMS Phase-2 upgrade, better resolution is expected for key observables.

In this study, we use a custom Monte Carlo simulation to compare the expected performance of Drell-Yan measurements in Run 2 and in the HL-LHC era (Run 4). We focus on single-lepton variables (such as transverse momentum and pseudorapidity) and dilepton variables (such as invariant mass and transverse momentum). The results show that the upgraded CMS detector improves the resolution of all these observables, with the clearest improvement in the muon transverse momentum and dimuon mass. A more detailed overview of these findings will be provided during the presentation.

Speaker: Marijus Ambrozas (Vilnius University (LT))

16.23_Ambrozas.pdf

Prospects for Drell-Yan Precision Measurements with the CMS Phase-2 Detector at the HL-LHC

18:30 → 22:30 Conference dinner

Thursday 16 October

09:20 → 10:20 Accelerator Technologies and Computing

Convener: Dr Mindaugas Šarpis

09:20 A novel approach to quench protection and detection of superconducting magnets

Quenches are a major issue for superconducting magnets because of their high current density which translates to high stored magnetic energy and eventually heat dissipation that may cause irreversible damage if left unadressed. The objective of this work is to describe the experimental demonstration of a novel quench detection and protection principle, combining a superconducting coil with a co-wound normal-conducting secondary coil. Similar to a co-wound voltage tap, the presence of the secondary coil allows for inductive noise suppression, thus facilitating low-noise quench detection. After quench detection, discharging the superconducting coil over an energy extractor featuring diodes and resistors gives rise to a very quick initial discharge of the superconducting coil. Following the quench-back principle, the induced currents in the secondary coil quickly heat up the cold mass and trigger a homogeneous quench. A major benefit of this rapid quench transformation principle is that, compared to quench protection configuration featuring energy extraction without quench-back, the needed voltage over the energy extractor is reduced by more than one order of magnitude.
To experimentally show the principle, a demonstrator magnet consisting of co-wound Nb-Ti and Cu conductors with an open warm bore size of 400 mm was assembled and tested inside a LHe bath. During testing,the magnet was ramped to nominal current of 200 A without training quenches while producing a B-field of 0.8 T at center of the bore. The operational parameters were measured and agree with calculated results. The detection threshold voltage of quenches is verified at common electromagnetic noise-inducing frequencies by an inductively coupled pick-up coil paired with a signal generator.
Following the experimental demonstration of the rapid quench transformation principle, a redesign of the magnet cooling system from using a LHe bath to operating with a cryo-cooler was made. This involves implementing thermal shields, REBCO + Cu current leads to enable cryo-cooled operation of the Nb-Ti magnet. The objective is to minimize the main sources of heat in this system: Joule heating in the current leads, conductive heat load onto the cold mass & thermal radiation. Efforts for assembling an experimental setup for the cryo-cooled Nb-Ti magnet with REBCO current leads are ongoing.

Speaker: Eino Johannes Tiirinen (CERN)

A novel approach to quench protection and detection of superconducting magnets

Development of a Nb-Ti solenoid demonstrator for RQT and conduction cooling_final.pdf

Development of a Nb-Ti solenoid demonstrator for RQT and conduction cooling_final.pptx

09:40 Accelerator projects, activities and progress with AM by RTU

Accelerator projects aimed at enhancing technological innovations are a necessity for the accelerator community to build the future machines for research and industrial applications. Additive manufacturing (AM), as a promising tool to provide larger design freedom than conventional manufacturing techniques, has been explored already several years. Riga Technical University (RTU) experience, activities, achievements and lessons learned with AM in the Innovation Fostering in Accelerator Science and Technology (I.FAST) project, that are closing to the end and challenges for further developments in the next projects.

Speaker: Andris Ratkus (Riga Technical University (LV))

Accelerator projects, activities and progress with AM by RTU

AT__CERN_AM_16.10.2025__full_2.pdf

AT__CERN_AM_16.10.2025__full_2.pptx

10:00 Status of the Latvian WLCG Tier 2 site

Fundamental research in high-energy physics (HEP) requires the distribution, processing and storage of a truly huge amount of data collected by the large experiments situated at the Large Hadron Collider (LHC) at CERN. Furthermore, the statistical nature of this research requires an equally vast amount of Monte-Carlo (MC) sample generation. To cope with the immense computing resource demands of HEP, a dedicated network of data processing sites, the World-wide LHC Computing Grid (WLCG), was established. WLCG is structured in multiple tiers, with individual universities and research institutions usually contributing at the Tier-2 level.

Latvia established its own Tier-2 site dedicated to processing data and MC for the Compact Muon Solenoid (CMS) experiment at CERN. The site currently comprises 9 worker nodes with a total of over 500 CPU cores and more than 4 TB of RAM, and operates using ARC-CE + SLURM batch systems, backed by xRootD storage endpoint.
In this contribution, we discuss the aims for establishing the Tier-2 site, its status and performance, as well as the future plans.

Speaker: Igors Makarkins (Riga Technical University (LV))

CBC2025 CERN CMS TIER2 Project-20251016 (1).pptx

CBC2025 CERN CMS TIER2 Project-20251016 (2).pdf

Status of the Latvian WLCG Tier 2 site

10:20 → 10:40 Coffee break

10:40 → 12:00 Atomic, Nuclear & Detector Physics

Convener: Dr Karlis Dreimanis

10:40 Laser Photodetchment Threshold Spectroscopy of Negative Ions

In this report I’ll tell about our activities within a project supported from Latvian Council of Sciences “Laser Photodetchment Threshold Spectroscopy of Negative Ions“. Within our project the participation in 3 different experiments from the list of active experiments on ISOLDE. Firstly Electron Affinity measurements on Clorine [1], and Polonium [2] as next. And latr we joined the parity non conservation studies on negative ions [3].
Due to our expertise in isotope shift measurements in electron affinities of Chlorine [4] we were invited to join the MIRACLS group [5] working on trapping the Chlorine anions during summer 2022. In early 2024 experiments were continued on GANDALPH [6]. I have to mention that the results recently were submitted in Nature Communication and will be published there in nearest future.
Finally, I’ll report on our experimental facility in the lab at University of Latvia, and I will reveal my vision for our future experiments.

Acknowledgment.
Project is supported by Fundamental and Applied Research Project (Nr. lzp-2023/1-0199): “The Laser Photodetachment Spectroscopy on Negative Ions”, from Latvian Science Council.

References:
1. Hanstorp D./ Wellander J., Measurement of shifts in the electron affinities of chlorine isotopes IS643, P515 https://isolde.web.cern.ch/active-experiments.
2. Nicols M./ Hanstorp D., Measuring the electron affinity of polonium IS728, P654 https://isolde.web.cern.ch/active-experiments.
3. Garcia Ruiz, R. / Flanagan, K.Study of RaF− anions at CRIS. IS758, P701 https://isolde.web.cern.ch/active-experiments.
4. U. Berzinsh, et.al., (1995)., “Isotope shift in the electron affinity of chlorine,” Phys. Rev. A 51, 231)4. Sels S., et al (2020), Nucl.Instrum. Meth. B, Vol 463 310-314 5. https://isolde.cern/index.php/miracls
6. Rothe S., et al (2017), J. Phys. G: Nucl. Part. Phys. 44 1040032

Speaker: Dr Uldis Bērziņš (Institute Of Atomic Physics And Spectroscopy, University of Latvia)

10.40_Uldis.pdf

Laser Photodetchment Threshold Spectroscopy of Negative Ions

11:00 Spectrosocpy of radioactive 221Fr and RaF- in ISOLDE facility at CERN

*On behalf of CRIS collaboration

Isotope Separator On Line DEvice (ISOLDE) at CERN is a unique source of low-energy beams of radioactive nuclides. Collinear Resonance Ionization Spectroscopy (CRIS) is one of the ongoing experiments located at the ISOLDE facility and one of the frontiers in the search for physics beyond standard model.
Francium, (particularly its 7S1/2 → 6D3/2,5/2 transitions) is a promising object of study for atomic parity violation. 221Fr+ was produced from a pre-irradiated uranium carbide source and was neutralized in a charge exchange cell. 9P1/2,3/2, 10P1/2,3/2 and 6D3/2,5/2 states in 221Fr were characterized via laser spectroscopy and a novel, background-free detection scheme was successfully implemented for the first time.
Radioactive molecules are extremely exciting prospect of study to explore major questions about the universe, but so far, they have not been extensively studied due to technical difficulties of their production and measurement. RaF ions were produced from the same uranium carbide source, whereafter it was fluorinated. The initially produced RaF+ ions were converted to RaF- by double charge exchange. Photodetachment of a radioactive molecule (RaF-) was succesfully demonstrated in ISOLDE facility for the first time. In future studies, it is planned to use the photodetachment of negative molecular ions to produce neutral molecules with controlled excitation levels. This would enable much more precise probing of energy states, compared to molecules produced directly from a hot source, or charge exchange cell, where the population is distributed over many energy levels.

Speaker: Janis Snikeris (Gothenburg University (SE))

11.00_Snikeris.pdf

Spectrosocpy of radioactive 221Fr and RaF- in ISOLDE facility at CERN

11:20 Studies of Novel Si n-Type Low Gain Avalanche Detectors Irradiated with High-Energy Protons

Low Gain Avalanche Detectors (LGADs) are the technology of choice for the timing detectors of the upcoming ATLAS and CMS upgrades at the High-Luminosity Large Hadron Collider (HL-LHC) due to their good timing resolution and signal-to-noise (S/N) ratio. Their performance, however, is limited for low-penetrating particles in p-type devices, since the charge multiplication mechanism differs for electrons and holes. A novel approach based on n-type LGADs, developed at Centro Nacional de Microelectrónica (IMB-CNM, Spain), addresses this limitation and shows potential for applications such as low-energy particle and soft X-ray detection. Although mainly intended for non-High-Enegy Physics (HEP) fields, these devices are also relevant for HEP R&D, allowing direct comparison with conventional p-type LGADs.

In this work, electrical and charge collection studies of n-LGADs and PiN structures fabricated at IMB-CNM are presented. Devices were irradiated with 23 GeV protons to fluences up to $\Phi = 2.5 \times 10^{15}\ \text{p/cm}^2$, including stepwise irradiation of one sample up to $\Phi = 1 \times 10^{13}\ \text{p/cm}^2$. Results from capacitance-voltage (C–V), current-voltage (I–V), Transient Current Technique (TCT), and edge-TCT measurements are reported and compared.

Speaker: Margarita Biveinyte (Vilnius University (LT))

M. Biveinyte nLGAD CBC2025.pdf

Studies of Novel Si n-Type Low Gain Avalanche Detectors Irradiated with High-Energy Protons

11:40 Selective Laser Etching for the Electrodes of Glass-based Micro-pattern Gaseous Detectors

In this work, we report the experimental results of studies aimed at producing electrodes for glass-based micropatterned detectors, employing selective laser etching. Femtosecond laser technologies allow for achieving multi-photon absorption in optically transparent materials such as fused silica (glass) due to their extremely high peak power and short pulse durations. The laser-affected region of glass transforms at an atomic level, making it selectively etchable. This is enabled by laser pulses of 290 fs duration and 515 nm wavelength with a 50 kHz repetition rate and average power of 200 mW. This laser microfabrication enables the creation of complex three-dimensional microstructures in the laser-modified volume of via selective laser-assisted chemical etching [1]. This technology was applied in producing the electrodes for Electron Multiplier (GEM), which is a type of fast timing and high-gain Micro-Pattern Gaseous Detector (MPGD), that is used in particle physics for ionizing radiation detection. We demonstrate that the electrodes are compatible with microelectronic structures in which the distance between the anode and cathode is on a millimeter or sub-millimeter scale. Such ionization detectors can be operated in aggressive radiation environments such as CERN's Large Hadron Collider (LHC) experiment [2]. Using subtractive and additive manufacturing, we constructed a prototype of GEM-type MPGD that is composed of a stack of several compactly packed single amplification stages assembled into a single detector, with the readout electronics at the bottom. Multiple amplification stages of such a detector provide a higher total gain of the signal, as all subsequent stages multiply the signal further. Each amplification electrode is realized as a dielectric substrate covered by a conductive film (copper) from both sides and patterned in a dense array of microscopic through-holes, integrated into the readout structure [2]. As a GEM detector achieves avalanche ionization through the concentration of electric field lines due to the cylindrical symmetry of holes in the amplification electrodes, we show that a thin glass substrate can serve as an efficient electrode with the performance of the detector determined by the shape of the holes [3]. We expect that selectively etched cylindrical holes will provide more stable detector operation, avoiding discharges between the anode and cathode that are usually recorded at high gains.

References:
[1] A. Butkute et al., 3D selective laser glass etching, 2020.
[2] F. Sauli, Gas electron multiplier (GEM), 2016.
[3] H. Takahashi et al., Glass GEM development, 2013.

Speaker: Ms Ugnė Lukaševičiūtė (Kaunas University of Technology)

11.40_Ugne.pdf

Selective Laser Etching for the Electrodes of Glass-based Micro-pattern Gaseous Detectors

12:00 → 12:10 Conference close