This is a curated list of events relevant to the CERN community.
More events are available here: home.cern/events
Indico also shows ALL events happening today, this week and in a calendar view.
If you would like your event to appear on an upcoming Bulletin events list, please contact bulletin-editors@cern.ch
"Women and Girls in Science and Technology" – Share your passion, inspire the scientists of tomorrow!
For the ninth consecutive year, CERN, UNIGE, EPFL, and LAPP are teaming up to celebrate the International Day of Women and Girls in Science. During the week of February 10 to 14, 2025, female scientists and engineers will visit schools in the region to inspire younger generations to explore the world of science.
As science ambassadors, you’ll have the opportunity to share your journey, talk about your projects and professional experiences, and even perform small demonstrations. Our goal is to transform students’ perceptions of scientific, technical, and technological careers and make them accessible to both girls and boys. Who knows, your visit might inspire future scientists!
Every year, Women and Girls in Science and Technology Week is a great success. In 2024, over 263 presentations were delivered by 100 ambassadors to 5,836 students! We are always looking for more female scientists willing to dedicate some time to visit schools. Join the adventure and sign up!
ALICE finds first ever evidence of the antimatter partner of hyperhelium-4
Illustration of the production of antihyperhelium-4 (a bound state of two antiprotons, an antineutron and an antilambda) in lead–lead collisions. (Image: J. Ditzel with AI-assistance)
Collisions between heavy ions at the Large Hadron Collider (LHC) create quark–gluon plasma, a hot and dense state of matter that is thought to have filled the Universe around one millionth of a second after the Big Bang. Heavy-ion collisions also create suitable conditions for the production of atomic nuclei and exotic hypernuclei, as well as their antimatter counterparts, antinuclei and antihypernuclei. Measurements of these forms of matter are important for various purposes, including helping to understand the formation of hadrons from the plasma’s constituent quarks and gluons and the matter–antimatter asymmetry seen in the present-day Universe.
Hypernuclei are exotic nuclei formed by a mix of protons, neutrons and hyperons, the latter being unstable particles containing one or more quarks of the strange type. More than 70 years since their discovery in cosmic rays, hypernuclei remain a source of fascination for physicists because they are rarely found in nature and it’s challenging to create and study them in the laboratory.
In heavy-ion collisions, hypernuclei are created in significant quantities, but until recently only the lightest hypernucleus, hypertriton, and its antimatter partner, antihypertriton, have been observed. A hypertriton is composed of a proton, a neutron and a lambda (a hyperon containing one strange quark). An antihypertriton is made up of an antiproton, an antineutron and an antilambda.
Following hot on the heels of an observation of antihyperhydrogen-4 (a bound state of an antiproton, two antineutrons and an antilambda), reported earlier this year by the STAR collaboration at the Relativistic Heavy Ion Collider (RHIC), the ALICE collaboration at the LHC has now seen the first ever evidence of antihyperhelium-4, which is composed of twoantiprotons, an antineutron and an antilambda. The result has a significance of 3.5 standard deviations and also represents the first evidence of the heaviest antimatter hypernucleus yet at the LHC.
The ALICE measurement is based on lead–lead collision data taken in 2018 at an energy of 5.02 teraelectronvolts (TeV) for each colliding pair of nucleons (protons and neutrons). Using a machine-learning technique that outperforms conventional hypernuclei search techniques, the ALICE researchers looked at the data for signals of hyperhydrogen-4, hyperhelium-4 and their antimatter partners. Candidates for (anti)hyperhydrogen-4 were identified by looking for the (anti)helium-4 nucleus and the charged pion into which it decays, whereas candidates for (anti)hyperhelium-4 were identified via its decay into an (anti)helium-3 nucleus, an (anti)proton and a charged pion.
In addition to finding evidence of antihyperhelium-4 with a significance of 3.5 standard deviations, as well as evidence of antihyperhydrogen-4 with a significance of 4.5 standard deviations, the ALICE team measured the production yields and masses of both hypernuclei.
For both hypernuclei, the measured masses are compatible with the current world-average values. The measured production yields were compared with predictions from the statistical hadronisation model, which provides a good description of the formation of hadrons and nuclei in heavy-ion collisions. This comparison shows that the model’s predictions agree closely with the data if both excited hypernuclear states and ground states are included in the predictions. The results confirm that the statistical hadronisation model can also provide a good description of the production of hypernuclei, which are compact objects with sizes of around 2 femtometres (1 femtometre is 10-15 metres).
The researchers also determined the antiparticle-to-particle yield ratios for both hypernuclei and found that they agree with unity within the experimental uncertainties. This agreement is consistent with ALICE’s observation of the equal production of matter and antimatter at LHC energies and adds to the ongoing research into the matter–antimatter imbalance in the Universe.
A tale of two Higgs: CMS searches for the production of Higgs boson pairs
Event display of a candidate event for Higgs boson pair production. (Image: CERN)
Since the CMS and ATLAS experiments announced the discovery of the Higgs boson in 2012, they have been measuring its mass and interaction with other particles with ever-increasing precision. Now, researchers are setting their sights on the Higgs boson’s interaction with itself, which could provide physicists with clues to the stability of the Universe. To do this, physicists search for a much rarer phenomenon than the production of one Higgs boson: the production of Higgs boson pairs, known as di-Higgs. In a new study, using data from high-energy proton–proton collisions in Run 2 of the Large Hadron Collider (LHC), the CMS experiment has released its latest search for di-Higgs production and provided constraints on their production rate.
Higgs boson pairs can be created in two main ways. The first is called gluon–gluon fusion, where gluons – particles inside the colliding protons – interact to produce the Higgs bosons. This process allows scientists to study the interaction between one so-called intermediate-state and two final-state Higgs bosons. The second method involves quarks, also inside the colliding protons, that radiate two vector bosons. These vector bosons then interact to form Higgs bosons, enabling the study of interactions between two Higgs bosons and two vector bosons.
Physicists at CMS performed their most recent analysis by searching for multiple ways that di-Higgs could decay. These final states resulted from Higgs boson pairs decaying to bottom quarks, W bosons, tau leptons and photons. By combining these searches and analysing all the data simultaneously using sophisticated analysis techniques – including boosted decision trees and deep neural networks – the collaboration was able to extract more information than ever before.
The study allowed physicists to establish upper limits on the rates of Higgs boson pair production with a 95% confidence level. The measured limits are currently at 3.5 times the Standard Model expectation for the total production of di-Higgs, and 79 times the Standard Model expectation for its production by fusing vector bosons.
With the Run 3 data-taking era of the LHC in progress, the CMS experiment has already doubled the amount of data collected, and CMS researchers are in the process of analysing it. One of the most interesting prospects for measuring the Higgs boson self-interaction is the upcoming High-Luminosity LHC (HL-LHC), scheduled to start operation in 2030. In this new phase, the accelerator will deliver to CMS the highest luminosity ever reached at a collider. Considering projections of luminosity and systematic uncertainties, scientists have estimated that they might start to see the first evidence for di-Higgs production with around half of the HL-LHC data. The collaboration looks forward to exploring this rare and exciting phenomenon further.
A flagship CERN open science programme – the Sponsoring Consortium for Open Access Publishing in Particle Physics (SCOAP3) – celebrated its tenth anniversary in 2024. It is a one-of-a-kind partnership between CERN and more than 3000 libraries, funding bodies, research institutes and intergovernmental organisations from across the world who, through collective action, have transformed research publishing in the discipline to make it open access, without any fees for readers or authors.
Having sustained this service as a global public good for a decade, SCOAP3 now aims to foster the general advancement of open science. To this end, it has introduced a new Open Science Mechanism, which will financially incentivise participating publishers based on their adoption of open-science practices. The mechanism will begin in January 2025, coinciding with the start of the fourth phase of SCOAP3.
“By incentivising publishers, who play a key role in interfacing with researchers, we aim not only to improve the quality of their publishing services, but also to advance the community’s adoption of open-science practices,” says Kamran Naim, Head of Open Science at CERN. “This will help foster accelerated, efficient, reproducible and transparent research in particle physics.”
The Open Science Mechanism will assess the performance of publishers in delivering certain open-science-related elements in their publishing workflows, such as adopting persistent identifiers (ORCiDs and RORs) for authors and institutions; improving the availability of linked data and software related to research articles; enriching article metadata for enhanced discoverability; improving accessibility and encouraging the adoption of open peer review practices. Publishers will further be incentivised to disclose their efforts on matters related to sustainability, data privacy, financial transparency and diversity, equity and inclusion. These will be made publicly available on the SCOAP3 website.
Over the last ten years, SCOAP3 has established barrier-free open-access publishing as the disciplinary norm, and has almost doubled in size to include supporters from almost fifty countries. It has centrally funded the open-access publishing of more than 70 000 articles across 11 leading particle physics journals, and is also the principal mechanism by means of which CERN’s researchers comply with the CERN Open Access Policy, automatically funding around 50% of the Organization’s research publications.
A meeting in December 2013 before the signing of SCOAP3. (Image: CERN)
In recent years, SCOAP3 has expanded the scope of its efforts to support the availability of more than 100 relevant open-access textbooks and monographs through an ongoing books initiative. “SCOAP3 has grown significantly in both size and scope over the past decade,” continues Naim. “As any collective action is only as strong as its base of support, we hope to see the SCOAP3 community grow further in the coming years with the addition of new members across non-participating CERN Member States, Associate Member States and beyond.”
Buy your Geneva public transport tickets at the CAGI kiosk
The International Geneva Welcome Centre (CAGI) cultural kiosk at CERN is now an official point of sale for TPG, the Geneva public transport company. Conveniently located in CERN’s Main Building, the kiosk now offers the following TPG services:
Purchasing tickets and travel cards
Buying or renewing transferable subscriptions
Renewing your personal subscriptions
Reloading your TPGPay card
Please note that tickets, cards and subscriptions are sold at standard TPG prices and this service is offered exclusively in person at the kiosk, remote purchases are not available.
As well as TPG services, the kiosk also offers discounted tickets to local cultural and sporting events (which can make great gifts). It also provides information and resources about living and integrating in the local area.
For more information and offers, you can visit their website, subscribe to their weekly newsletter, or visit the CAGI kiosk at CERN, open from Monday to Friday, from 8.30 a.m. to 11 a.m., and from 11.30 a.m. to 2.30 p.m.
The test stand for the High-Luminosity LHC welcomes its first magnets
The magnets that direct and focus the beams just before the collision point are one of the jewels of the High-Luminosity LHC (HL-LHC), the major upgrade of the LHC. The first magnets will be tested on a unique test stand at CERN, known as the IT (Inner Triplet) String. This test facility, located in a building on the surface, is an exact replica of the machine segments that will be installed on both sides of the ATLAS and CMS experiments.
"The aim of the test stand is to check how these magnets behave collectively when integrated with their powering systems and their innovative cryogenic cooling, protection and alignment systems and to test the installation procedures,", explains Marta Bajko, head of the IT String project.
After the impressive installation of the power supply system in September, two magnet assemblies have recently been installed in what was a complex and delicate operation (watch the video below). The first of these assemblies consists of a superconducting quadrupole magnet made at CERN and a correction magnet. The quadrupole magnet is one of the inner triplets that will squeeze the particles together more tightly to increase the luminosity of the accelerator. It’s one of the new generation of magnets that are made of the superconductor niobium–tin instead of the niobium–titanium used for the LHC’s current magnets. These new magnets generate more intense magnetic fields of 11.3 tesla, compared with 8.6 tesla, which allows them to better focus the beams. It took many years to develop them, with their winding and the use of the superconductor posing particular challenges.
"Developing magnets that generate very high magnetic fields is one of the major challenges for the accelerators of the future. Using quadrupole magnets with niobium–tin coils in the HL-LHC for the first time marks an important milestone”, explains Susana Izquierdo Bermúdez, who is in charge of the construction of the HL-LHC superconducting magnets.
The cryostat of this quadrupole magnet also contains a correction magnet that was manufactured as part of a collaboration between CERN and CIEMAT and CDTI in Spain. "This correction magnet has a novel mechanical structure. It corrects the trajectory of the particle beams by generating a magnetic field of up to 4.1 tesla," explains Juan Carlos Perez, the CERN engineer in charge of the project.
The second cryostat installed on the test stand contains a dipole magnet known as a separation and recombination magnet. This magnet directs the beams on each side of the experiments to make them collide and then separate. Made of niobium–titanium like the dipole magnets in the LHC, it generates a field of 5.6 tesla. It was manufactured and tested at KEK in Japan.
In early 2025, an assembly of two quadrupole magnets that have been made in the United States is due to arrive at the test stand, which will be fully assembled by the summer The next step will be quality tests and cryogenic cooling to 1.9 K by the end of the year. 2026 will be a key year as the entire system will be tested in conditions equivalent to those of the tunnel.
For more information about the installation of the magnets on the HL-LHC test stand, read the article on the project website.
On 4 November, the separation and recombination dipole magnet manufactured by the Japanese institute KEK was transported to CERN and installed at the High-Luminosity LHC test facility. (Video: CERN)
Throughout 2024, CERN celebrated its 70th anniversary with a rich programme of events that took place in more than 70 cities around the world. The operation of CERN’s accelerator complex was remarkable in every respect and resulted in outstanding physics results.
The United Nations has declared 2025 as the International Year of Quantum Science and Technology, marking 100 years of research and innovation in the field. Join CERN as we celebrate the centenary, highlighting the Organization’s research into quantum effects and its enabling technologies that accelerate next-generation quantum innovations.
You can create your own personalised electronic cards by signing in with your CERN account on this site. You can choose from three background designs, as seen in the slideshow below.
CERN Community: take part in the 2024 CERN end-of-year crossword!
The LHC Lego set, available at the CERN shop. (Image: CERN)
2024 has been another busy year for CERN. If you fancy testing your knowledge, why not take part in the CERN 2024 end-of-year crossword? You could be in with a chance of winning a full LHC Lego set (worth 98 CHF), two CAGI Pathé Balexert cinema tickets (worth 16.90 CHF each) or limited edition CERN70 merchandise.
Send your answers from your CERN email address to bulletin-editors@cern.chbefore 6 January 2025. Your answers can be in the form of a completed crossword or a numbered list.
All correct entries will be entered into a prize draw. The prize winners will be announced in the first Bulletin of 2025.
Please note: you must have a CERN email address to enter the prize draw.
Good luck!
CERN 2024 END OF YEAR CROSSWORD
ACROSS
1. In September, the ATLAS and CMS experiments released results on what weird quantum phenomenon?
4. The CMS experiment released the most precise mass measurement of a Standard Model particle to date on 17 September. What was the name of the particle?
6. At the end of November, Arts at CERN launched a new arts residency programme in collaboration with the Republic and Canton of Geneva and the City of Geneva. What is the name of this programme?
7. CERN Science Gateway is among the “100 greatest places in the world”, according to which famous American magazine?
9. What do you get if you unscramble the shaded letters?
12. Which Swiss fitness initiative awarded the CERN community the prize for the best participation rate in its category?
13. This prominent scientist died earlier this year at the age of 94.
17. What is the name of the first South American country to join CERN as an Associate Member State (on 22 March 2024)?
20. Which subproject of the antimatter factory rehearsed the transportation of antimatter in October?
21. Fill in the blank: the CERN alumni network brought more than 600 people together in February for a large networking event and reunion, known as its ____ Collisions.
22. In February, the AEgIS experiment paved the way for a new set of antimatter studies by cooling positronium with what type of light?
23. In a recent result, which CERN experiment revealed a new source of atmospheric aerosol particles that could help scientists to refine climate models?
DOWN
2. To celebrate CERN70, CERN exhibitions appeared in multiple locations around Geneva, including in which major city amenity?
3. Estonia became a CERN Member State on 30 August, becoming the first Baltic country to join CERN as a full Member State. CERN now has how many Member States?
5. What is the acronym for the newly reopened former main reception, now serving the CERN community?
8. Fill in the blank: CERN’s next Director-General, who was selected by the CERN Council in November and who is set to start his mandate on 1 January 2026, is named ____ Thomson.
10. Using collisions between lead nuclei at the LHC, the ALICE collaboration measured an interference pattern similar to which physicist’s famous double-slit experiment?
11. Throughout the year, the LHCb experiment has conducted studies on a phenomenon that could help explain the asymmetry between matter and antimatter in the Universe. What is this phenomenon?
13. Spanning more than 6000 square metres, the new CERN data centre was inaugurated in February on which of the CERN sites?
14. Fill in the blank: the CERN and Society Foundation celebrated its ___ year anniversary in 2024.
15. Fill in the blank: performers at the CERN70 community event in September included “Les _____ Cernettes”.
16. CERN has signed three power purchase agreements to provide electricity from what type of renewable source from 2027?
18. Launched in January 2024, the project HORIZON-ZEN aims to ensure that a tool developed by CERN makes EU research data as findable, accessible, interoperable and reusable as possible. What is this tool called?
19. In June, which LHC experiment released the results of its most sensitive search yet for di-Higgs production using data from Run 2?
Reminder: documents required for Schengen area entry, stay and exit
When crossing a border to enter or leave the Schengen Area1, as well as when travelling from one country to another within the Schengen Area (including crossing the local borders between the canton of Geneva and the départements of Ain and Haute-Savoie), it is essential to carry a valid identity document (e.g. passport2) that is recognised by the country you are entering. Unless they are specifically exempt, all nationals of countries other than the Member States of the European Economic Area3 and Switzerland must also carry a valid residence permit (residence or settlement permit issued by a Schengen state or passport containing a Schengen visa). In the absence of these documents, entry into the country concerned may be refused.
As is the case for everyone travelling within the Schengen Area, members of the CERN personnel may be subject to an identity check and must be able to present a recognised identity document.
When leaving the Schengen Area, nationals of countries other than the Member States of the European Economic Area and Switzerland who hold those documents must check that they are valid for the duration of their stay outside the Schengen Area. If the documents have expired or you are unable to present them, you may be refused entry on your return.
In case of difficulties at the borders, immigration authorities of the Schengen area may contact:
for Switzerland, the International Security Police at Geneva Airport, tel. +41 22 427 58 30 (until midnight) or tel. n° +41 22 427 92 20 (24 hours a day);
for France, the Protocol of the Ministry for Europe and Foreign affairs, tel. +33 (0)1 53 69 30 20 (diplomatic privileges and immunities) / +33 (0)1 53 69 37 69 (consular privileges and immunities), on working days and hours.
If the the French special card or Swiss legitimation card is lost, stolen or forgotten during a stay abroad, the persons concerned are invited to contact directly either the French or the Swiss representation competent for the place of stay in order to obtain a return visa.
Future Circular Collider innovation and the economics of big science
An artist’s view of the tunnel for the FCC-ee (electron–positron collider) (Image: Polar Media)
Two events in Brussels have highlighted the potential of the Future Circular Collider (FCC) to support new innovations and strengthen Europe’s global competitiveness.
On 24 October, the final event of the FCC Innovation Study (FCCIS) celebrated the achievements of this EU Horizon 2020 project as it concluded its four-year journey that began in November 2020. Preceding this, a book launch of “The Economics of Big Science 2.0”, published as part of the project, took place on 23 October.
The Future Circular Collider Innovation Study (FCCIS) EU Horizon 2020 project analysed more than 100 placement scenarios with different layout geometries and surface sites in support of the ongoing FCC Feasibility Study. (Image: CERN)
The FCCIS supported the ongoing FCC Feasibility Study by setting up structures to enable collaboration by a worldwide community. It carried out placement studies that weighed geological and territorial constraints against machine requirements and physics performance, and made progress with beam studies, prototype development, collider and booster accelerator designs, beam dynamics evaluations and measurement techniques.
This open access book, with contributions from international researchers and policymakers, is available online for free and expands on concepts introduced in the first edition from 2021.
Speakers at the FCCIS event included José Luis Martínez, Chair of the European Strategy Forum on Research Infrastructures (ESFRI), and Alexandr Hobza, formerly Chief Economist at the European Commission’s (EC) Directorate-General for Research and Innovation and newly appointed expert in the cabinet of the EC Executive Vice-President. Both emphasised the important role that research infrastructures play in boosting European competitiveness.
The FCCIS also contributed to the development of sustainability guidelines for future particle accelerators, aligning with recommendations from the EC and ESFRI. These guidelines, due to be published in 2025, will help to evaluate the socioeconomic impact of research infrastructures. In a similar vein, the book launch of “The Economics of Big Science 2.0” underscored the potential of big science to create lasting societal benefits.
“I am proud that we have financed the feasibility study for CERN’s future circular collider. This could preserve Europe’s scientific edge, and it could push the boundaries of human knowledge even further,” said Ursula von der Leyen, President of the European Commission, referring to the FCCIS contribution to the ongoing FCC Feasibility Study in her speech at the official ceremony for CERN’s 70th anniversary.
The FCCIS project is one example of strong cooperation between CERN and the EC, which supports projects and initiatives led by research infrastructures, such as ATTRACT. This cooperation, carried out in the framework of a 2009 Memorandum of Understanding, recognises CERN’s role in elevating Europe’s standing as a leading global hub for research and innovation, and 2024 saw many valuable discussions at different levels. Strong cooperation with the EC is particularly timely and relevant in the light of the new Commission having taken office on 1 December and the publication of the strategic high-level reports “Much more than a market” by Enrico Letta in April and “The future of European competitiveness” by Mario Draghi in September, with the latter explicitly mentioning the FCC and calling for concrete support for it by the EC.
“We are striving to significantly step up the current level of cooperation with the EC,” emphasises Raphaël Bello, CERN Director for Finance and Human Resources. “We are now at a turning point in CERN’s history: without the EC, CERN’s next flagship project, whether it is the FCC or another option, may not happen. Maintaining CERN’s global leadership at a time of geopolitical competition in science and technology is a top strategic priority not just for CERN’s Member States but for the European Union as a whole.”
The conclusion of the FCCIS project marks a major step forward for the preparation of the FCC Feasibility Study final report, due in March 2025 ahead of the next update of the European Strategy for Particle Physics.
Within CERN’s archives lies a letter dated 20 December 1954 from Sir Ben Lockspeiser, the then Council chairperson to the Director General and staff of CERN:
“This is to bring you all the best wishes of Council for CERN’s First Christmas. An organisation in its early years inevitably encounters difficulties, and an organisation such as CERN which is not only new but is creating something new is bound to encounter its fair share. But enough has already been achieved to give confidence that CERN will move steadily to fulfil its purpose and grow in strength to achieve its aim. The progress of CERN has only been made possible by the devotion of all those engaged in the enterprise, and in wishing you a happy New Year the Council knows that it can count on this devotion during the coming year”
Icicles hang from the barracks next to Geneva airport in December 1954. These were the offices of some of CERN’s first employees. Read about makeshift radiators to keep warm in Franco Bonaudi’s CERN70 recollections. (Image: CERN) (Image: CERN)
See how CERN grew from that first year until now by revisiting the CERN70 feature series, full of recollections from those who were there at the time.
You can send your own wishes for the year ahead via the CERN e-card website.
Early exploration of quantum technologies – both within the scientific domain and on the wider societal level – is essential, even if it may take decades before they are ripe for everyday use. The rapid rise of artificial intelligence underlines the importance of understanding, as early as possible, the potential impact of emerging technologies. With this in mind, the United Nations International Year of Quantum Science and Technology (IYQ) in 2025 will provide a global framework to inform about, discuss and reflect on the status and future of quantum technologies, including their implications for the current global societal challenges.
The CERN Quantum Technology Initiative (QTI) began in 2018 with a workshop on Quantum Computing in High-Energy Physics. This kick-off event explored the state of the art of quantum research and identified opportunities for collaboration between academia and industry. Six years on, the QTI is now in its second phase and benefits from established partnerships. It has identified three core areas – quantum computing, networking and sensing – where future technologies are expected to make significant contributions to CERN’s scientific mission.
More recently, CERN opened its doors to the Open Quantum Institute (OQI), a multilateral platform incubated by GESDA that brings together stakeholders from academia, industry, diplomacy and education. The raison d’être of the OQI is promoting inclusive access to quantum computing and the advancement of its applications for the benefit of society.
Through initiatives like the QTI and OQI, CERN is contributing to research and fostering international collaboration, with a focus on making quantum technologies accessible to a broad audience. The participation of CERN and OQI in the IYQ underscores our commitment to exploring the applications of quantum technologies and sharing knowledge widely.
The IYQ inaugural event at the UNESCO Headquarters in Paris on 4 and 5 February 2025 will be followed by a series of initiatives and events worldwide, which will offer opportunities to learn about and engage with quantum science. At CERN, the 2025 public event season will be devoted to this quantum year. Events in CERN Science Gateway are set to include talks, performances, a film festival and more, and the programme will be available from January 2025 via visit.cern/events.
The International Year of Quantum Science and Technology aims to ensure that this transformative technology is developed and understood in a way that benefits everyone.
Front cover of the CERN 2024/2025 greeting card, celebrating 2025 as the year of quantum science and technology. (Image: CERN)
Accelerator Report: A well-deserved winter break for the accelerator complex
If experimental physicists had their way, CERN’s accelerator complex would run nonstop, 365 days a year, without a winter break. However, the machines in the accelerator complex, along with their many subsystems, require regular maintenance to stay in topnotch condition, especially as some of them are getting quite old.
Take the Proton Synchrotron (PS), for example, the oldest operational machine at CERN. On 24 November, it celebrated its 65th anniversary, an age at which many people retire, but not the PS! Instead, it will continue to play a central role in the production of nearly all the beams within the accelerator complex for years to come, thanks to the care and attention of the many people who carry out preventive and corrective maintenance to maintain good availability as well as upgrades to further enhance its performance.
An overview of the excellent availability of beam for most of the experimental facilities in the injector complex. The availabilities indicated are cumulative, which means that the figures given include the availability of the upstream machines. For example, the availability of the beam out of ELENA contains the unavailability of Linac4, PSB, PS, AD and ELENA itself. (Image: CERN)
This winter stop began gradually on 25 November, when the LHC was stopped. The same day the beam from the PS Booster (PSB) to ISOLDE was stopped, leaving the Proton Synchrotron (PS) as the PSB’s only client. However, the ISOLDE team and some of the experiments continued running for another two weeks without the PSB’s proton supply.
During this ISOLDE winter physics run, a pre-irradiated target was installed in the location where targets usually receive the proton beam from the PSB. This target has already been exposed to a substantial amount of proton beam in the past and continues to produce isotopes. These isotopes were separated and directed as usual down the transfer lines to some of the experiments, allowing ISOLDE physics to continue even without fresh protons. This 2024 winter physics run was also successfully accomplished. In 2024 the PSB delivered 1.25x1020 protons, which means that 66% of the total amount of protons accelerated by the PSB (1.9x1020) was consumed by ISOLDE.
Meanwhile, the Neutron Time-of-Flight facility (n_TOF) also concluded its physics run on 25 November, having received an impressive 1.39x1019 protons on its target in 2024. With this, the PS focused on delivering protons and lead ions to the remaining facilities – the antiproton decelerators (AD and ELENA), the East Area and the SPS – before stopping operations entirely on 2 December.
Although CERN’s accelerator complex shut down on 2 December, some systems remain active. The ELENA machine, which usually decelerates antiprotons, will continue to deliver negatively charged hydrogen ions (H⁻) to the GBAR experiment until the end of the week. Meanwhile, the BASE experiment still has its trap filled with antiprotons collected over a year ago and will carry out physics experiments during the winter shutdown. For BASE, the YETS is the ideal time for measurements, as the absence of pulsing equipment means no electromagnetic disturbances, improving the precision of their data.
While many staff will work in the tunnels during the YETS and the accelerators take their winter break, the CERN Control Centre (CCC) will remain staffed. The Technical Infrastructure team will operate 24/7 to monitor the technical systems and quickly address any issues that arise, ensuring smooth operation also throughout the annual closure.
As this time of year is perfect for sharing wishes, here are mine: if I could make a Christmas wish, it would be for another incredible run in 2025, with beam performance and availability at least matching, and preferably surpassing, the successes of 2024.
Best wishes to everyone, and don’t forget to reconnect with us in 2025 to stay updated on all the exciting developments in the accelerator complex!
Annual adjustments to financial benefits with effect from 1 January 2025
In accordance with recommendations made by the Finance Committee and decisions taken by Council in December 2024, the following financial benefits will be adjusted, with effect from 1 January 2025:
A 1.21% increase to the scale of basic salaries paid to Staff Members and the scale of stipends paid to Fellows and Graduates (Annexes R A 5 and R A 6 of the Staff Regulations).
A 0.6% increase to the subsistence allowances (Annex R A 7 of the Staff Regulations), family, child and infant allowances (Annex R A 3 of the Staff Regulations) and to payment ceilings of education fees (Annex R A 4 of the Staff Regulations).
The index of 2.24% for home leave has already been applied as of June 2024.
The new ceiling of education fees will be applied to the entire school year 2024-2025.
Other related adjustments have been implemented wherever applicable to associated members of the personnel (2025 subsistence rates).
In accordance with recommendations made by the Finance Committee and decisions taken by Council in December 2024 (CERN/FC/6866-CERN/3861), please find below the pages of the Staff Rules and Regulations which have been updated further to the modifications coming into force on 1 January 2025:
Annex R A 3 of the Staff Regulations, (Family allowances), modification of page 68
Annex R A 4 of the Staff Regulations, (Education fees), modification of page 69
Annex R A 5 of the Staff Regulations, (Monthly basic salaries of staff members), modification of page 71
Annex R A 6 of the Staff Regulations, (Stipends of graduates and fellows), modification of page 72
Annex R A 7 of the Staff Regulations, (Subsistence allowances of associated members of the personnel), modification of page 73
The complete updated electronic version of the Staff Rules and Regulations is accessible via CDS.
Composition of the Joint Advisory Appeals Board (JAAB/CPCR)
Appointed by the Director-General
Appointed by the Staff Association
Members
Valeria PEREZ REALE / TE
François DUVAL / EP
1st deputies
Joël CLOSIER / EP
Nicolas SALOMON / PF
2nd deputies
Raymond VENESS / SY
Silvia SCHUH-ERHARD / BE
Valeria Perez Reale and François Duval have drawn up the following list of staff members from among whom the Chairperson of the Board may be chosen when required:
Jan BORBURGH / SY
Pedro MARTEL / EN
François BRIARD / IR
Jesper NIELSEN / BE
Isabel FERNANDEZ GONZALEZ/ SCE
Chiara PASQUINO / SY
Silvia GRAU / EN
Laurent ROY / EP
Nils HOIMYR / IT
Jens VIGEN / RCS
Mediators [see Administrative Circular N° 6 (Rev. 1) entitled "Review procedure"] will also be selected from this list of ten staff members.
CERN Health Insurance Scheme (CHIS) – Monthly contributions as of 1 January 2025
The CHIS contribution rates are unchanged for 2025, but the contributions themselves will evolve due to the change in the relevant Reference Salary (see Chapter XII of the CHIS Rules). Thus, as of 1 January 2025, the lump-sum monthly contributions based on Reference Salary II will be as follows:
Lump-sum contributions for voluntary members
The monthly contribution for voluntary members (e.g. users and associates) with the normal health insurance will be 1 287 CHF per month, whilst for those with the reduced health insurance it will be 644 CHF.
Lump-sum contributions for post-compulsory members other than CERN pensioners
For post-compulsory members other than CERN pensioners, the monthly contribution will be 1 375 CHF in the case of former staff members awaiting a deferred pension and former spouses continuing their affiliation, whilst in the case of formerly dependent children continuing theirs it will be 550 CHF.
2024 holds special significance for CERN, as it celebrated its 70th anniversary. To mark this major milestone, the Organization held a series of public events in the CERN Science Gateway around the overarching themes: Unveiling the Universe, Exploring Farther: Machines for New Knowledge, Virtuous Circle of Knowledge and Innovation and Extraordinary Human Endeavour. It also held a CERN70 Community Event and an Official Ceremony for Heads of State and Government, along with celebrations organised in the Member and Associate Member States across the globe. The Office for Alumni Relations hosted its Third Collisions event, a major reunion that welcomed 600 alumni at CERN.
CERN’s innovations have reverberated far beyond particle physics exemplifying the Virtuous Circle of Knowledge and Innovation. CERN brought together key stakeholders in global health and one of the flagship projects known as STELLA is re-engineering radiotherapy to make it accessible for low- and middle-income countries. A collaboration with EUROfusion is driving forward innovative technologies for future colliders and nuclear fusion reactors. AI-driven projects like Edge SpAIce will help tackle marine plastic pollution, leveraging CERN’s expertise in data management, and the White Rabbit Collaboration has launched a new open-source technology to sync devices in the accelerators down to sub-nanoseconds, promising applications far beyond particle physics. The Organization also celebrated the first anniversary of CERN Venture Connect initiative, a launchpad for deep-tech startups, and the tenth anniversary of the CERN and Society Foundation.
CERN inaugurated a new data centre with integrated heat-recovery system to address the data-processing needs of the worldwide scientific community and launched the Next-Generation Triggers project to significantly increase the efficiency, sensitivity and modelling of the ATLAS and CMS experiments.
Having marked seven decades of discovery in 2024, CERN now looks forward to another 70 extraordinary years of scientific research and global collaboration and welcomes 2025, the International Year of Quantum Science and Technology.
