Subscribe to RSS - News feed
Updated: 2 hours 2 min ago

CERN’s accelerators gear up for action after the winter maintenance break

Wed, 21/02/2024 - 12:32
CERN’s accelerators gear up for action after the winter maintenance break

As winter bids farewell, the recommissioning of CERN’s accelerator complex gathers pace, with the scientific community eagerly awaiting particle beams in their experiments. Following the traditional winter break (called the “year-end technical stop” (YETS)), the Linear accelerator 4 (Linac4) is the first machine to resume beam operation, followed by the downstream machines: the Proton Synchrotron Booster (PSB), Proton Synchrotron (PS), Super Proton Synchrotron (SPS) and Large Hadron Collider (LHC).

Beam entered Linac4 on 5 February, and the PS Booster a few days later. This week, the first beam was injected into the PS, which is now preparing the first beam for the SPS beam commissioning, scheduled to start on 1 March. The first particle beams will reach the LHC on 11 March.

The expectations for 2024 are high. In the LHC, the focus is on luminosity production with proton–proton collisions. The luminosity is an important indicator of the performance of an accelerator: it is proportional to the number of collisions that occur in the experiments in a given amount of time. The higher the luminosity, the more data the experiments can gather to allow them to observe rare processes.

The 2024 LHC run will conclude with lead–lead ion collisions; the first lead ions will be injected into the LHC on 6 October. The 2024 run is scheduled to end on 28 October.

The resumption of operation of the accelerator complex heralds a new year of physics, surely leading to important physics results. As the countdown to 11 March continues, the operations and other expert teams are working diligently to prepare the machines and the beams for another successful physics run.

anschaef Wed, 02/21/2024 - 11:32 Byline Rende Steerenberg Publication Date Thu, 02/22/2024 - 09:31

CMS collaboration explores how AI can be used to search for partner particles to the Higgs boson

Tue, 20/02/2024 - 14:21
CMS collaboration explores how AI can be used to search for partner particles to the Higgs boson Event display showing two collimated bursts of light. (Image: CMS collaboration)

As part of their quest to understand the building blocks of matter, physicists search for evidence of new particles that could confirm the existence of physics beyond the Standard Model (SM). Many of these beyond-SM theories postulate the need for additional partner particles to the Higgs boson. These partners would behave similarly to the SM Higgs boson, for example in terms of their “spin”, but would have a different mass.

To search for Higgs partner particles, scientists at the CMS collaboration look for the signatures of these particles in the data collected by the detector. One such signature is when the particles decay from a heavy Higgs partner (X) particle to two lighter partner particles (φ), which in turn each decay into collimated pairs of photons. Photon signatures are ideal to search for particles with unknown masses as they provide a clean, well-understood signature. However, if the φ is very light, the two photons will significantly overlap with each other and the tools usually applied for the photon identification fall apart.

This is where artificial intelligence (AI) comes in. It is well known that machine learning computer vision techniques can differentiate between many faces, and now such AI methodologies are becoming useful tools in particle physics.

The CMS experiment searched for the X and φ partners of the Higgs boson using the hypothetical process X→φφ, with both φ decaying to collimated photon pairs. To do this, they trained two AI algorithms to distinguish the overlapping pairs of photons from noise, as well as to precisely determine the mass of the particle from which they originated. A wide range of masses was explored. No evidence for such new particles was seen, enabling them to set upper limits on the production rate of this process. The result is the most sensitive search yet performed for such Higgs-like particles in this final state.

How can the scientists test the AI’s effectiveness? It is not as easy as verifying AI facial differentiation, where you can simply check by looking. Thankfully, the SM has well-understood processes, which CMS physicists used to validate and control the AI techniques. For example, the η meson, which also decays to two photons, provided an ideal test bench. Scientists at CMS were able to cleanly identify and reconstruct the η meson when searching for its decay into photons when they applied these AI techniques.

This analysis clearly shows that AI algorithms can be used to cleanly identify two-photon signatures from the noise and to search for new massive particles. These machine learning techniques are continuously improving and will continue to be used in unique analyses of LHC data, extending CMS searches to even more challenging cases.

Read more here



ndinmore Tue, 02/20/2024 - 13:21 Byline CMS collaboration Publication Date Wed, 02/21/2024 - 09:30

AEgIS experiment paves the way for new set of antimatter studies by laser-cooling positronium

Fri, 16/02/2024 - 15:50
AEgIS experiment paves the way for new set of antimatter studies by laser-cooling positronium

AEgIS is one of several experiments at CERN’s Antimatter Factory producing and studying antihydrogen atoms with the goal of testing with high precision whether antimatter and matter fall to Earth in the same way. In a paper published today in Physical Review Letters, the AEgIS collaboration reports an experimental feat that will not only help it achieve this goal but also pave the way for a whole new set of antimatter studies, including the prospect to produce a gamma-ray laser that would allow researchers to look inside the atomic nucleus and have applications beyond physics.

To create antihydrogen (a positron orbiting an antiproton), AEgIS directs a beam of positronium (an electron orbiting a positron) into a cloud of antiprotons produced and slowed down in the Antimatter Factory. When an antiproton and a positronium meet in the antiproton cloud, the positronium gives up its positron to the antiproton, forming antihydrogen.

Producing antihydrogen in this way means that AEgIS can also study positronium, an antimatter system in its own right that is being investigated by experiments worldwide.

Positronium has a very short lifetime, annihilating into gamma rays in 142 billionths of a second. However, because it comprises just two point-like particles, the electron and its antimatter counterpart, “it’s a perfect system to do experiments with”, says AEgIS spokesperson Ruggero Caravita, “provided that, among other experimental challenges, a sample of positronium can be cooled enough to measure it with high precision”.

This is the feat accomplished by the AEgIS team. By applying the technique of laser cooling to a sample of positronium, the collaboration has already managed to more than halve the temperature of the sample, from 380 to 170 degrees kelvin. In follow-up experiments the team aims to break the barrier of 10 degrees kelvin.

AEgIS’ laser cooling of positronium opens up new possibilities for antimatter research. These include high-precision measurements of the properties and gravitational behaviour of this exotic but simple matter–antimatter system, which could reveal new physics. It also allows the production of a positronium Bose–Einstein condensate, in which all constituents occupy the same quantum state. Such a condensate has been proposed as a candidate to produce coherent gamma-ray light via the matter-antimatter annihilation of its constituents – laser-like light made up of monochromatic waves that have a constant phase difference between them.

“A Bose-Einstein condensate of antimatter would be an incredible tool for both fundamental and applied research, especially if it allowed the production of coherent gamma-ray light with which researchers could peer into the atomic nucleus.” says Caravita.

Laser cooling, which was applied to antimatter atoms for the first time about three years ago, works by slowing down atoms bit by bit with laser photons over the course of many cycles of photon absorption and emission. This is normally done using a narrowband laser, which emits light with a small frequency range. By contrast, the AEgIS team uses a broadband laser in their study.

“A broadband laser cools not just a small but a large fraction of the positronium sample,” explains Caravita. “What’s more, we carried out the experiment without applying any external electric or magnetic field, simplifying the experimental set-up and extending the positronium lifetime.”

The AEgIS collaboration shares its achievement of positronium laser cooling with an independent team, which used a different technique and posted their result on the arXiv preprint server on the same day as AEgIS.

Further material:
Video collection
Photo collection 1
Photo collection 2

About AEgIS:
The AEgIS collaboration is composed of several research groups from CERN, Istituto Nazionale di Fisica Nucleare (units of Milano, Pavia and the Trento Institute for Fundamental Physics and Applications), the University of Oslo, the Universite Paris-Saclay and the Centre National de la Recherche Scientifique, the University of Liverpool, the Warsaw University of Technology, the University of Trento, the Jagiellonian University of Krakow, the Raman Research Institute of Bangalore, the University of Innsbruck, the University and the Politecnico of Milan, the University of Brescia, the Nicolaus Copernicus University in Torun, the University of Latvia, the Institute of Physics of the Polish Academy of Sciences and the Czech Technical University of Prague.

sandrika Fri, 02/16/2024 - 14:50 Publication Date Thu, 02/22/2024 - 16:30

Accelerator Report: The accelerator complex gears up for action after the yearly winter maintenance break

Thu, 15/02/2024 - 11:11
Accelerator Report: The accelerator complex gears up for action after the yearly winter maintenance break

The symbolic key to resume LHC operations will be handed over from the ACE (Accelerator Coordination and Engineering) group in the Engineering department to the Operations group on Friday, 16 February, kicking off the 2024 “particle season”.

As winter bids farewell, the recommissioning of the accelerator complex gathers pace, with the scientific community eagerly awaiting particle beams in their experiments. Following the year-end technical stop (YETS), Linac4 is the first machine to resume beam operation, followed by the downstream machines: the PS Booster, PS, SPS and LHC.

Beam entered Linac4 on 5 February, two days ahead of schedule – extra time welcomed by the Linac team. During the YETS, work was done on the chain of accelerating cavities, requiring a re-phasing – a challenging and often time-consuming task. To do so, the acceleration of the particle beam is optimised as the beam goes down the Linac: the voltage waves in the cavities are timed correctly as the beam passes by, ensuring optimum acceleration in each of the cavities and bringing the energy to 160 MeV at the end of the Linac.

This week, the beam was then sent to the PS Booster. The operations team has one week to prepare for the first beam to be injected into the PS on 21 February. The PS will then have to prepare the first beam for the SPS beam commissioning, scheduled to start on 1 March. The first particle beams will reach the LHC on 11 March, initially with one to a few bunches at most.

Before injecting particle beams, the hardware recommissioning coordinators of each machine and the many equipment experts have the task of meticulously recommissioning and validating all the subsystems. They run the machine “as if” particle beams were being accelerated, but without particles. They go through checklists, validating and ticking off thousands of tests, to give the green light for beam commissioning.

The expectations for 2024 are high. Firstly, in the LHC, the focus is on luminosity production with proton–proton collisions, aiming at an unprecedented accumulation of luminosity of up to 90 fb-1. This, together with the accumulation of luminosity forecast for the 2025 run, should provide a sizeable analysis data set to keep physicists busy during Long Shutdown 3. The 2024 LHC run will conclude with lead–lead collisions; the first lead ions will be injected into the LHC on 6 October. The 2024 run is scheduled to end on 28 October.

The injector chain has an ambitious year ahead as well: the injectors have a busy fixed-target programme and will provide beams to all the experimental facilities. The first fixed-target physics will start in the PS East Area on 22 March, followed by the PS n_TOF facility on 25 March. Physics in ISOLDE, downstream of the PS Booster, will start on 8 April, followed by the SPS North Area on 10 April. The antimatter factory is set to start delivering antiprotons to its experiments on 22 April. The AWAKE facility, behind the SPS, will run for ten weeks in total (in blocks of two or three weeks) until the middle of September, when the dismantling of the no-longer-used CERN Neutrinos to Gran Sasso (CNGS) target facility will start, to allow for a future extension of the AWAKE facility. The SPS HiRadMat facility will see four 1-week runs.

Beyond this busy physics programme, many machine development studies and tests are planned in all the machines. One of these tests will take place between mid-March and early June to configure the Linac3 source to produce magnesium ions, which will be accelerated in Linac3, injected into LEIR, and possibly even into the PS. This test will help assess the feasibility and performance of magnesium beams in the accelerator complex, for potential future applications in the LHC and the SPS North Area.

The resumption of operation of the accelerator complex heralds a new year of physics, surely leading to important physics results. As the countdown to 11 March continues, the operations and expert teams are working diligently to prepare the machines and the beams for another successful physics run.

anschaef Thu, 02/15/2024 - 10:11 Byline Rende Steerenberg Publication Date Thu, 02/15/2024 - 10:08

Happy hundredth Herwig!

Wed, 14/02/2024 - 13:11
Happy hundredth Herwig! Learn from a lifetime of physics, come to the 1 March event.

Join in a rousing chorus of “Happy Birthday” on Friday 1 March, as CERN celebrates the 100th birthday of Herwig Schopper, CERN Director-General from 1981 to 1988.

Herwig has made landmark contributions to nuclear and particle physics and to related technologies. In his early career, he played a key role in shaping today’s physics research landscape in Germany, establishing laboratories and institutions before going on to leadership roles at DESY and CERN.

After retirement, not content to rest on his laurels, Herwig embarked on a new career: as a science diplomat. In this capacity, he played a leading role in the establishment of the SESAME laboratory in Jordan, a synchrotron light facility for the Middle East and neighbouring regions.

Over his remarkable career, Herwig has rubbed shoulders with the giants of the field, counting many as friends. Few have had the opportunity to witness the evolution of particle physics from such a privileged vantage point.

Now is your chance to hear this history first hand. On Friday 1 March from 2 p.m. in the Main Auditorium, current and former CERN directors, eminent scientists and Herwig himself will speak, before participants are invited to raise a glass at a drinks reception. Full details are available here.

Register now to join the celebration of Herwig’s life and achievements to date.

(Video: CERN)

katebrad Wed, 02/14/2024 - 12:11 Publication Date Thu, 02/15/2024 - 09:30

Computer Security: Bull**** Bingo

Tue, 13/02/2024 - 15:50
Computer Security: Bull**** Bingo

There are many mantras and claims floating around about cybersecurity. Some of them leave no room for doubt, like “defence in depth”, which suggests deploying protective means at every level of the hardware and software stack, or “KISS ─ keep it simple, stupid” to avoid over-complication and too many deviations from the “standard” cybersecurity system. Other, more unfortunate statements also hold true. For example, “convenient, cheap, secure ─ pick two” makes “secure” always the least attractive option, as it brings no immediate benefits. However, some other mantras and claims are simply not true. Plain wrong. Or, excuse my language, “bull****”.

Indeed, computer security is never straightforward. Often, there is no single solution, but a series of complementary solutions is needed, like how our xorlab ActiveGuard solution works together with the Microsoft SPAM filter. Often a holistic solution cannot be found, for example when the quick fix of having two-factor authentication (2FA) for the new CERN SSO was deployed, which meant that the old SSO was left to die, and the non-holistic solutions we are looking at for how to deploy 2FA to LXPLUS and Windows Terminal Servers in the future. Generally, computer security requires the aforementioned “defence in depth”: individually, multiple protective layers, each with a defined (implementation) scope, a limited coverage and holes are insufficient. But together, they provide adequate overall protection to the Organization that is pragmatic, balanced and efficient. Combined, they keep the cybersecurity risks and threats to the Organization under control.

So, while we acknowledge that there is no single solution to “cybersecurity”, there are many wrong solutions. Wrong statements. Wrong mantras. Bull****. In order to give you an idea of what we mean, let’s play “Bull**** Bingo”. Below are 25 statements we have heard in the past about cybersecurity, best security practices and cybersecurity implementation, some even from esteemed colleagues. Can you spot where they went wrong?  








There is no malware for Apple devices

Software from the Google Play Store is harmless

Security is everyone’s responsibility

SSH on port 2222/tcp is more secure

SPAM and malware filtering is 100% effective


2FA is a big step forward for account protection

Emails from “” are legitimate

I'm personally not a target as I'm not interesting to attackers

Back-ups cannot be altered

I have nothing to hide


I would never fall for phishing

Only the link behind a text/QR code reveals its truth

CERN’s technical network is secure

A password written on a post-it is a good idea

QR codes always link to legit sites


A (free) VPN service protects me

Password protection on my laptop protects its data

My browser’s password manager is secure

CERN is not interesting to attackers

CERN’s anti-malware software is free for you to download


Using “https” means the website is secure

CERN’s outer perimeter firewall keeps all threats away

Cloud services cannot be hacked

Encryption is easy; key management is complicated

WiFi is always secure


The first three people to send  the five true statements to will win a bottle of Coca-Cola, as well as a “Hawaiian” pizza from CERN’s Restaurant 2.

Want to learn more about computer security incidents and issues at CERN? Read our monthly reports ( For more information, questions or advice, check out our website ( or contact us at

ndinmore Tue, 02/13/2024 - 14:50 Byline Computer Security team Publication Date Tue, 02/13/2024 - 14:46

Science Gateway welcomes its 100 000th visitor

Tue, 13/02/2024 - 15:39
Science Gateway welcomes its 100 000th visitor

On Tuesday, 6 February, CERN Science Gateway welcomed its 100 000th visitor.

Bavo Lens and Nicky Morren came from Hasselt to Geneva on a city break and said “visiting CERN is a must”.

“For me, as an engineer, it was great to be able to see high-tech machines like the Synchrocyclotron and ATLAS,” Lens said. “Congratulations to the guide who was able to explain the very complex material in understandable language. The reception building is very beautiful and offers wonderful exhibitions that explain how particle research works very clearly, even for those who are not gifted in science. We ended our visit in the restaurant, where we enjoyed the vegetarian options!”

Since the opening of CERN Science Gateway on October 8 2023, an average of 1000 visitors per day have enjoyed this new facility. The centre offers activities for all ages, including inviting young visitors from five years old to play and “see the invisible” while building up an interest in and connection to science and technology.

Having reached this milestone, the Visits service would like to send a big “thank you” to all its active guides. None of this would have been possible without the enormous dedication of each and every one of them, volunteering day after day to ensure that our visitors have an inspiring experience. 

For those who have not yet found the time to become a guide: take the first step and become part of this new era of outreach and education at CERN. The first step is usually the biggest, but the team will be there to support you at every stage of the journey.

ndinmore Tue, 02/13/2024 - 14:39 Publication Date Tue, 02/13/2024 - 14:37

CERN Council reviews progress of feasibility study for a next-generation collider

Tue, 13/02/2024 - 11:48
CERN Council reviews progress of feasibility study for a next-generation collider

After three years of work, mobilising the expertise of scientists and engineers around the world, the Feasibility Study for the Future Circular Collider (FCC) - a particle collider with a circumference of 90.7 km that could potentially succeed the High-Luminosity LHC in the mid-2040s – has now reached the half-way mark. The Feasibility Study is expected to be completed in 2025.

The CERN Council reviewed the work undertaken in a fruitful meeting on 2 February 2024. It congratulated and thanked all the teams involved in the study for the excellent and significant work done so far and for the impressive progress, and looks forward to receiving the final report in 2025.

Particle colliders have played a crucial role in elucidating the fundamental laws of nature and constituents of matter. The Feasibility Study for the FCC was launched in response to a recommendation from the 2020 update of the European Strategy for Particle Physics, whereby Europe, in collaboration with the worldwide community, should undertake a technical and financial feasibility study for a next-generation hadron collider at the highest achievable energy, with an electron-positron collider as a possible first stage.

If approved by CERN’s Member States in the coming years, the construction of the first stage, an electron-positron collider (FCC-ee), could start in the early 2030s and operate in the mid-2040s. The facility would operate for some 15 years, during which time the high-field magnet technology needed for the second stage, a proton-proton collider operating at an unprecedented collision energy of around 100 TeV (FCC-hh), could be developed and industrialised.

Accelerator, detector, and physics studies continue within the global FCC collaboration, spanning 150 institutes in 30 countries.

Relevant links:

abelchio Tue, 02/13/2024 - 10:48 Publication Date Tue, 02/13/2024 - 10:39

Quadrupoles are red, dipoles are blue…

Mon, 12/02/2024 - 17:22
Quadrupoles are red, dipoles are blue…

CERN community: this Valentine’s Day we’re asking you to compose an ode to technology.

Send us your CERN-related Valentine’s poem, written in English or French, and we’ll publish our favourites in the next Bulletin. We’ll also give a prize to the poem that we like the best. Poems must be a maximum of 20 lines, and the more CERN-specific the better. 

Here are our attempts to get you started:

Quadrupoles are red
Dipoles are blue
CERN’s magnets are cool
They’re attractive too

Protons are red,
Electrons are blue,
There’s neutrons as well
But you are my glu(on)
There once was an experimentalist,
Who was a great friend of a theorist.
She said to him:
“I give thee this ring”
And LHC made them their happiest.

Send your poem to by midnight CET on Sunday, 25 February. Please note that you must have a CERN email address to enter.

By taking part in this competition, you accept that your poem may be published in the next CERN Bulletin. If you wish, you can request that we publish it anonymously.

(Video: CERN)

katebrad Mon, 02/12/2024 - 16:22 Byline Internal Communication Publication Date Wed, 02/14/2024 - 09:09

Record participation in the 2024 "Women and Girls in Science and Technology" event!

Mon, 12/02/2024 - 16:24
Record participation in the 2024 "Women and Girls in Science and Technology" event!

From 5 to 9 February, more than eighty female ambassadors from CERN, the University of Geneva, EPFL and LAPP spoke to 5800 local pupils, giving over 260 presentations in the space of a week! Their goal: to get children excited about science and break down gender stereotypes about scientific jobs.

The Women and Girls in Science and Technology event has been an annual fixture since 2017, marking the International Day of Women and Girls in Science, which is celebrated on 11 February. The event’s eight editions have met with increasing success, thanks to an ever-expanding cohort of ambassadors eager to share their passion. In total, more than 24 500 pupils aged between 7 and 15 from the local region have seen for themselves that careers in science, technology, engineering and mathematics are equally accessible to girls and boys.

Are you a teacher who would like to take part in the 2025 event? Sign up for our education newsletter to find out what we offer and when registration will be open!

Would you like to take part in the 2025 event as a volunteer? Contact the CERN events team to find out about our upcoming calls for volunteers!

Update on the “25 by ’25” strategy

(Image: CERN)

In spring 2021, the Diversity & Inclusion programme launched the “25 by ’25” strategy, an aspirational target-based initiative to boost the gender and nationality diversity of CERN’s staff and fellows population (MPEs) by the end of 2025. Objective: to reach 25% of women among MPEs by the end of 2025.

The latest statistics (see graphic) are very encouraging: CERN is only 1.3% away from its target!


The International Particle Physics Outreach Group (IPPOG) has engaged communities in particle physics for more than 25 years. IPPOG also holds dedicated International Masterclasses for girls and women on the occasion of International Day of Women and Girls in Science and Technology.

anschaef Mon, 02/12/2024 - 15:24 Byline Mélissa Samson Publication Date Mon, 02/12/2024 - 15:18

Hearing the sound of quark–gluon plasma

Thu, 08/02/2024 - 12:44
Hearing the sound of quark–gluon plasma

Neutron stars in the Universe, ultracold atomic gases in the laboratory, and the quark–gluon plasma created in collisions of atomic nuclei at the Large Hadron Collider (LHC): they may seem totally unrelated but, surprisingly enough, they have something in common. They are all a fluid-like state of matter made up of strongly interacting particles. Insights into the properties and behaviour of any of these almost perfect liquids may be key to understanding nature across scales that are orders of magnitude apart.

In a new paper, the CMS collaboration reports the most precise measurement to date of the speed at which sound travels in the quark–gluon plasma, offering new insights into this extremely hot state of matter.

Sound is a longitudinal wave that travels through a medium, producing compressions and rarefactions of matter in the same direction as its movement. The speed of sound depends on the medium’s properties, such as its density and viscosity. It can therefore be used as a probe of the medium.

At the LHC, the quark–gluon plasma is formed in collisions between heavy ions. In these collisions, for a very small fraction of a second, an enormous amount of energy is deposited in a volume whose maximum size is that of the nucleus of an atom. Quarks and gluons emerging from the collision move freely within this area, providing a fluid-like state of matter whose collective dynamics and macroscopic properties are well described by theory. The speed of sound in this environment can be obtained from the rate at which pressure changes in response to variations in energy density or, alternatively, from the rate at which temperature changes in response to variations in entropy, which is a measure of disorder in a system.

In heavy-ion collisions, the entropy can be inferred from the number of electrically charged particles emitted from the collisions. The temperature, on the other hand, can be deduced from the average transverse momentum (i.e. the momentum transverse to the collision axis) of those particles. Using data from lead–lead collisions at an energy of 5.02 trillion electronvolts per pair of nucleons (protons or neutrons), the CMS collaboration has measured for the first time how the temperature varies with the entropy in central heavy-ion collisions, in which the ions collide head on and overlap almost completely.

From this measurement, they obtained a value for the speed of sound in this medium that is nearly half the speed of light and has a record precision: in units of the speed of light, the squared speed of sound is 0.241, with a statistical uncertainty of 0.002 and a systematic uncertainty of 0.016. Using the mean transverse momentum, they also determined the effective temperature of the quark–gluon plasma to be 219 million electronvolts (MeV), with a systematic uncertainty of 8 MeV.

The results match the theoretical expectation and confirm that the quark–gluon plasma acts as a fluid made of particles that carry enormous amounts of energy.

abelchio Thu, 02/08/2024 - 11:44 Byline CMS collaboration Publication Date Fri, 02/16/2024 - 11:41

Stories from CERN's women in science

Wed, 07/02/2024 - 11:46
Stories from CERN's women in science

Each year, on 11 February, CERN celebrates the International Day of Women and Girls in Science by shedding light on the variety of career paths for women in STEM. This year, we asked nine female scientists to share their stories with us and tell us what inspired them to pursue a STEM career and what are their favourite memories involving science.

Sorina, physicist at the CMS experiment

Sorina is a Romanian research physicist at the CMS experiment, working on heavy-ion research.

“My favourite thing about my job is the data analysis, as well as detector development and installation. I am very happy when I can work with the students. The most rewarding part of it is when I see their careers as physicists evolve.”

Jenny, PhD student at the ATLAS experiment

Jenny is a Norwegian doctoral student at the University of Oslo. She’s currently working on upgrading the pixel detector for the ATLAS experiment.

Science was her favourite class in school, which inspired her to pursue a career in STEM. “My curiosity for science started with what we can see in our everyday lives, for example how yeast makes bread dough rise, how a candle flame goes out if it loses access to oxygen, or how nature changes with the seasons.”

Pinelopi, PhD student with the Medipix collaboration

Pinelopi is a PhD student with the Medipix collaboration. Medipix chips developed for pixel detectors at the LHC are now used in a variety of fields, including medical imaging.

It was her family and her secondary school experiences that inspired Pinelopi to pursue a career in STEM. “My mother studied physics, so I wanted to become like her, while my father loves to explore ideas and think outside the box. As a secondary school student, I visited CERN with my class, and I was amazed by everything. My dream was to one day return as a physicist.”

Federica, PhD student at the LHCb experiment

Federica is an Italian doctoral student in particle physics, working on heavy-ion physics at the LHCb experiment. She is currently involved in putting the VELO detector into service.

Federica has always been curious about science and knew from an early age that she was going to pursue a STEM career. Her favourite memory involving science goes back to secondary school, when two CERN physicists visited her class to give a masterclass. “They built a hand-made cloud chamber for us, with things you could find in the kitchen, to detect the particles from cosmic rays. And I fell in love with particle physics!” remembers Federica.

Joni, physicist at the ATLAS experiment

Joni, a Vietnamese physicist from the University of Melbourne, focuses mainly on data analysis for heavy-ion collisions at the ATLAS experiment. She’s also involved in the operation of the ATLAS detector.

Joni is passionate about science communication and education activities, especially for the young generation. Her passion for science was triggered by her curiosity to explore – in her own words – “worlds that are physically unreachable and invisible to the naked eye, like atoms and subatomic particles”.

Joni shared with us a glimpse of one of her first big moments at CERN: “When I started working as a run control shifter, I was very nervous, but the shift leader, Clara Nellist, was very kind and supportive of the whole crew. Now that I've become a shift leader myself, I'm truly grateful to Clara and everyone I've had a chance to work with at CERN, who constantly encouraged me to move beyond my comfort zone.”

Livia, post-doc at the ALICE experiment

Livia, an Italian physicist, oversees the operation of the muon spectrometer of the ALICE experiment. She’s also doing research and development on silicon detectors for the upcoming ALICE detector upgrade.

Since secondary school, Livia has always been enthusiastic about science. The experiments in her school’s laboratory and her passion for research convinced Livia to pursue a STEM career.

When we asked Livia about her favourite moments at work, she didn’t hesitate: “The amazing and fun time I spent in the ALICE control room, waiting for the LHC beam to arrive, while preparing the detectors for data taking. The most fun for me is doing R&D on particle physics detectors, building them from scratch and then seeing them installed in the experiment caverns.”

Tetiana, physicist at the ATLAS experiment

Tetiana is a Ukrainian physicist from the Annecy Particle Physics Laboratory in France, working on the ATLAS experiment. She works on the upgrade of the electronics for an ATLAS calorimeter. She’s also searching for phenomena beyond the Standard Model.

When we asked what inspired her to pursue a STEM career, Tetiana told us that it was an obvious choice for her, as everyone in her family was either a scientist or an engineer. “I decided to do a PhD in physics and mathematics when I was 10 years old.”

Her favourite memory involving science from her childhood is growing “beautiful blue crystals from copper sulphate. They were growing on the kitchen windowsill in my home in Kharkiv next to jars of green onions.”

Deepti, engineer for the North Area Consolidation project

Deepti is an Indian scientist working on the project to consolidate CERN’s North Area experiment facility.

Deepti was always intrigued by the basic principles of science and their everyday utility. Her affinity for STEM kept growing over the years and she decided to pursue a career in mechanical engineering.

“During my childhood, I was fascinated by buoyancy, gravity, density and water displacement as I watched paper boats float on water. When I was a young child, I learned to make paper boats and put them on running water during the monsoon season in India.”

Alicia, PhD student in the accelerator field

Alicia is a Spanish doctoral student working on developing an ultra-fast generator for special magnets used in CERN’s accelerators.

During her engineering studies, she enjoyed being in the lab the most, which inspired her to choose this path.

“When I was still living in Madrid, I used to go to a secondary school that was very close to the Residencia de Estudiantes [student housing] and I loved that place: the buildings are beautiful, the garden that surrounds it, everything. And then I read a discreet sign that said that this was also a historical site of the European Physical Society. Marie Curie had been there, Einstein too… That may have had an influence on my choice of a degree!” says Alicia.

cmenard Wed, 02/07/2024 - 10:46 Byline Bianca Moisa Publication Date Wed, 02/07/2024 - 10:23

Introducing CERN’s robodog

Mon, 05/02/2024 - 18:19
Introducing CERN’s robodog

Building 937 houses the coolest robots at CERN. This is where the action happens to build and programme robots that can tackle the unconventional challenges presented by the Laboratory’s unique facilities. Recently, a new type of robot called CERNquadbot has entered CERN’s robot pool and successfully completed its first radiation protection test in the North Area.

“There are large bundles of loose wires and pipes on the ground that slip and move, making them unpassable for wheeled robots and difficult even for humans. We carried out a proof-of-concept survey with the Radiation Protection group in this area. There were no issues at all: the robot was completely stable throughout the inspection,” said Chris McGreavy, a robotics engineer in CERN’s Controls, Electronics and Mechatronics (CEM) group.

(Right to left) CERNquadbot with its counterpart, CERNBotNA – where NA stands for North Area. Together, these robots have completed a successful radiation protection survey inside CERN’s largest experiment area. (Image: M.Struik/CERN)

Until today, CERN’s family tree of robots included the modular CERNbot in different sizes and configurations, such as the CERNbotSPS, as well as the Train Inspection Monorail (TIM) and CRANEbot. They can carry heavy payloads like robotic arms and other tools but are limited when it comes to entering cluttered areas and moving over unstructured surfaces and on steps.

The team is now developing tools and advanced control algorithms for the robodog and its successors for long-term deployment in the experiment caverns, such as that of the ALICE detector, which are complex environments with metal stairs and narrow corridors designed for humans or, well, robots with legs. In collaboration with the Experimental Physics R&D department, the CEM group is developing this four-legged robot that will soon be able to manoeuvre throughout almost the entire cavern. These robodogs will be able to monitor the state of the caverns and their environmental conditions regularly. They can identify water or fire leaks and other incidents, such as false alarms, in a timely manner, all of which can significantly impact the operation of the machines in the caverns and tunnels.

Each robot developed at CERN is carefully crafted to meet unique challenges and to complement each other. For example, there are rails attached to the ceiling running along the 27-kilometre tunnel of the Large Hadron Collider (LHC). The TIM monorail robot uses these rails to move around the tunnel. While it is great for monitoring and interacting with the tunnels from above, CERN’s new small robodog can perform activities on the ground, especially under the beamline, where no robot could tread before so easily. It is envisaged to be integrated with the four monorail robots currently in operation in the LHC.

“The TIMs are used for monitoring the large distances of the LHC from above and can travel long distances without recharging. They can deploy the quadbots in local areas to get more information about specific places that the TIM cannot easily access,” explains McGreavy.

The robodog will be able to enter new dimensions of the caverns, unlike the previous wheeled, tracked or monorail robots – expanding the range of environments that CERN robots can navigate. The Beams department continues to dream up robots for CERN and engineer them into reality.

Watch CERN’s robodog at work:

ckrishna Mon, 02/05/2024 - 17:19 Byline Chetna Krishna Publication Date Tue, 02/06/2024 - 09:00

HiLumi News : protéger les composants du futur accélérateur du CERN

Wed, 31/01/2024 - 12:53
HiLumi News: protecting the components of CERN’s future accelerator

A major upgrade of the collimation system of the Large Hadron Collider (LHC) began during the first long shutdown of CERN’s accelerator complex (LS1, 2013–2015) and continued during LS2 (2019–2021), in preparation for the High-Luminosity LHC (HL-LHC). As its name suggests, the HL-LHC will surpass the LHC in terms of luminosity, i.e. the number of collisions that take place within the LHC experiments. The accelerator’s equipment therefore requires enhanced protection, which is where the collimation system comes in.

What is a collimator?
Collimators are movable blocks made of materials that can absorb particles. Shaped like jaws, they close tightly around the beam to clean up particles that stray from their path. The materials used for these jaws and their various components are capable of withstanding extremes of pressure and temperature, as well as high levels of radiation.

Why do beams need cleaning?
Particles that stray from the beam path could collide with sensitive accelerator components, such as superconducting magnets, and interfere with their operation or, in the worst case, damage them. To prevent this from happening, collimators are placed at strategic locations around the LHC ring, where they either absorb stray particles or deflect them towards beam dumps. Protection is particularly crucial in the vicinity of the experiments, where the beam size is reduced to increase the chances of collision.

The new collimators are double-beam collimators (here you can clearly see the two beam apertures side by side). This optimised configuration enables both beams to pass through the same vacuum chamber, thus freeing up space for the collimators' jaws. (Image: CERN)

The LHC currently has 118 collimators of different kinds. The future HL-LHC will have 126 collimators, including brand new models custom made at CERN. Recently, two new prototypes (TCLPX and TCTPXH) have been successfully developed and tested, under the supervision of François-Xavier Nuiry, engineer in charge of the HL-LHC collimator production. Destined for LHC interaction points 1 (ATLAS detector) and 5 (CMS detector), they are double-beam collimators. This optimised configuration enables two beams (circulating in opposite directions) to pass through the same vacuum chamber, thus freeing up space for the collimators’ jaws, which are thicker and more powerful in this location.

“These two prototypes are innovative in several ways,” explains Dylan Baillard, a mechanical engineer in CERN’s Targets, Collimators and Dumps section. “They are fitted with a remote alignment and levelling system, which helps reducing the radiation dose received by the teams working on them. The collimator flanges can be connected and disconnected more easily thanks to integrated connection tools. Finally, ion pumps are used to ensure an excellent vacuum quality because the collimators, which are close to the beams, always operate in a vacuum and must not disrupt the circulation of the beams.”

The final tests were successfully completed in December, and series production of the two new types of collimator should begin this year. Twelve double-beam collimators will be installed in the machine during Long Shutdown 3 (LS3, 2026–2028).

anschaef Thu, 02/01/2024 - 11:46 Byline Anaïs Schaeffer Publication Date Wed, 01/31/2024 - 11:49

HiLumi News: cool kickers for the HL-LHC

Wed, 31/01/2024 - 12:35
HiLumi News: cool kickers for the HL-LHC Installation of the MKI-Cool during the 2022–23 year-end technical stop. (Image: CERN)

Kicker magnets are an important part of the LHC accelerator complex. Installed at the intersection of the LHC ring and the SPS transfer lines, they give each injected beam a “kick” at the right time to put it into orbit in the LHC.

The higher luminosity of the HL-LHC will pose a challenge for these magnets, as increased heat load could result in a miskick of the injected beam. To avoid this, engineers in CERN’s Systems department have developed a new version of the kicker magnet for the HL-LHC, called an “MKI-Cool”. One such magnet was installed in the LHC one year ago, replacing a standard kicker magnet. Measurements during its first year of operation, with high-intensity beam, show that the temperature rise of the MKI-Cool is less than one-fifth of that of the other seven kicker magnets in the LHC. This confirms that no heating issues should occur for the MKI-Cool kicker magnets with HL-LHC beams.

“Based on this excellent result, all the kickers will be sequentially upgraded to MKI-Cools,” says Mike Barnes, senior engineer in CERN’s Systems department. “The full upgrade of the MKIs will be completed during Long Shutdown 3.”*

Unlike other magnets in the accelerator, kicker magnets cannot be fully shielded from the beam. Shielding would interfere with the fast magnetic field pulse that they provide to kick the beam. In addition, the high-voltage pulse required prevents the magnets from being water-cooled, which is a serious hurdle as the ferrite they are made from loses its magnetic properties above the temperature of 125 °C. Under these conditions, the MKIs would miskick the injected beams, causing the downstream magnets to lose their superconductivity.

Following years of research and development, the team came up with a new design. The MKI-Cool design works by moving most of the beam-induced heating from the ferrite yoke to a so-called RF damper, which contains a ferrite cylinder and is mounted just upstream of the magnet. The beam-induced heat is then removed from the RF damper using a water-cooling circuit.

“The concept of moving the heat was demonstrated in computer simulations, but it was very challenging to prove this in lab-based measurements,” Barnes continues. “Hence, to fully prove the concept, a prototype with an RF damper, which was not cooled, was installed in the LHC in 2018 and measurements of temperature, with circulating LHC beam, proved that the RF damper concept worked effectively.”

To measure the difference in the beam-induced heat load between the MKI-Cool and the old kicker magnets, the team used temperature sensors attached to a nearby metal side plate. It was not possible to directly measure the temperature of the ferrite because it is pulsed to a very high voltage during the beam injection.

“During 2023 LHC operation with the MKI, the measured temperature of both the RF damper and the side plate remained relatively low,” Barnes continues. “Based on these temperature measurements and simulations, no heating issues are expected for the MKI-Cool in the HL-LHC era.”

*Mike Barnes retired at the end of 2023: Giorgia Favia is now responsible for the MKI kicker magnets and will oversee the full upgrade to MKI-Cools.

ndinmore Wed, 01/31/2024 - 11:35 Byline SY department Publication Date Wed, 01/31/2024 - 11:32

The CERN Accelerator School celebrates 40 years

Wed, 31/01/2024 - 12:32
The CERN Accelerator School celebrates 40 years

The CERN Accelerator School (CAS) celebrated its 40th anniversary in the sunshine last September and with its contributors this January.

Back in the 1980s, a group of CERN scientists and engineers saw the need for an educational training programme in the rapidly evolving field of accelerator physics and technology. Textbooks on accelerator physics were sparse at the time, and courses at universities were practically non-existent. As Herwig Schopper, then CERN Director-General, put it: “An enormous amount of expertise is stored in the brains of quite a number of people […]. However, very little of this knowledge has so far been documented or published in book form.” It was into this landscape that the CERN Accelerator School was born in 1983.

The success of CAS in Europe quickly caught the attention of the global accelerator community, leading to a surge in demand for its courses. To accommodate this growing interest, CAS began organising courses outside Europe, in Asia and the Americas, from 1985, in collaboration with other institutions and organisations working in accelerator physics.

Over its 40-year-long history, more than 6000 participants from across the globe have been trained.

Find out more about the history, impact and future of the CERN Accelerator School in the latest CERN Courier:

anschaef Wed, 01/31/2024 - 11:32 Byline CERN Accelerator School Publication Date Wed, 01/31/2024 - 11:29

Accessible by design: how CERN Science Gateway exhibitions are tailored to people with visual impairments

Wed, 31/01/2024 - 10:43
Accessible by design: how CERN Science Gateway exhibitions are tailored to people with visual impairments A visitor from ABA testing the Discover CERN: Accelerate exhibition with her guide. (Image: CERN)

Since opening in October, CERN Science Gateway has welcomed almost 100 000 visitors. Among these was a group of around 50 people from the Association pour le Bien des Aveugles et malvoyants (ABA), the reference association in Geneva for blind and visually impaired people, who toured the exhibitions on 28 November. ABA has worked with the CERN exhibitions team since 2019 and this was the chance for its members, including some visually impaired members, to see the fruit of this collaboration.

At the event, Emma Sanders, head of the CERN exhibitions team, and Bernard Jost, ABA’s accessibility project manager, explained how they had developed the exhibitions with accessibility and inclusivity at the forefront.

“We learnt very early on that making content more accessible usually benefits more than one kind of audience group,” Emma explained. “Tactile content is great for people who are blind or who have visual impairments, but it is also appreciated by many children. Wheel-chair accessible furniture is also good for parents pushing kids in buggies.”

“The idea came from CERN,” says Jost. “While the law requires cultural sites in Geneva to be as accessible as possible, what’s praiseworthy about CERN Science Gateway is that they made a point of taking accessibility into account from the beginning. We haven't created a parallel accessible exhibition: it's the same exhibition with some additional accessible features.”

The exhibition Our Universe: Back to the Big Bang features a tactile timeline of the Universe. (Image: CERN)

The permanent Science Gateway exhibitions comprise three parts: Discover CERN, Our Universe and Quantum World. Many installations incorporate an audio description and many also include tactile features, where visitors can touch and explore to interpret the content for themselves.

“One of the exhibitions that impressed me the most was Discover CERN, where I was able to go around the tunnel that the particles pass through and, thanks to the guide's description, experience the entire journey they take. It was impressive,” says Anne Gaugaz, one of the ABA visitors with visual impairments. “I also liked, in Back to the Big Bang, being able to touch the planets of the solar system that were in relief. That helped me to understand how big they were.”

A visitor from ABA touring the ​​​​Discover CERN: Collide exhibition with his guide and guide dog. (Image: CERN)

“Thanks to the guided tour, I enjoyed my visit to the Science Gateway exhibitions, in particular the accelerator exhibition and the part that takes us back in time to the Big Bang. It was very interesting and informative,” says Bertram Paul, a blind member of the ABA group who also worked with the exhibitions team to advise on the audio descriptions.

While the visit in November was a success, there is still work to be done. “Of course, it’s an evolving process,” Jost continues. “Some more alterations need to be made, so we will keep in touch.”

Content designed for people with visual impairments is just one aspect of Science Gateway’s effort to be accessible to all. And to complement the exhibitions, there is now a new CERN guides course focusing on accessibility, which is run by another local group, Culture Accessible. Visit this link to find out how you can become a Science Gateway guide.

For colleagues across CERN who are interested in making their work more accessible, the exhibitions team can share more about the process. As Emma recommends, “It’s always easier to ensure accessibility when you build it in from the start of your project. Working together with the community is essential: it brings creative and sometimes unexpected solutions that often work better for everyone.”

ndinmore Wed, 01/31/2024 - 09:43 Byline Naomi Dinmore Publication Date Wed, 01/31/2024 - 09:33

Computer Security: 300 computer security articles and counting

Tue, 30/01/2024 - 12:03
Computer Security: 300 computer security articles and counting

We begin the year by celebrating the 300th Bulletin article focusing on various computer-security-related topics. Three hundred hopefully informative articles about the cybersecurity situation at CERN. About best practices, guidelines and useful tools. About risks, threat scenarios and attack vectors. About new or established means of mitigation. About the workings of the Computer Security team, the services and tools it’s providing and the complexity of its detection infrastructure. About policies and dos and don’ts. Three hundred articles trying to raise your awareness and help you improve your approach to computer security – the security of your laptops, smartphones and tablets, of your accounts and passwords, of your email inbox and web browser, of software programming and system development – both at CERN and at home.

While some articles were published a long time ago – the first ones were released in 2008 – they’ve never lost their relevance. Sometimes it’s useful to delve into the past and dig out information from them; often these articles also provide guidelines for us when advising users. So for this 300th anniversary, we have updated our compilation of all the articles published so far. This compilation covers a plethora of topics, sorted into the notorious themes of “computer security”, i.e. the literal cybersecurity of computers, “mobile and cloud security”, “network and data centre security”, “account and password security”, “control systems and IoT (Internet of Things)”, “secure software development”, “data protection and privacy”, “copyrights”, “rules and policies” and more. Giving a deeper insight into the computer security landscape, these articles complement our Monthly Reports, which usually depict the operational side of what’s currently happening at CERN.

You can download this compilation here. It’s public – published under CC-BY-NC-SA. So please feel free to share it with your colleagues, family and friends in order to spread the word, raise awareness and help them improve the security and protection of their own digital assets and resources!


Do you want to learn more about computer security incidents and issues at CERN? Follow our Monthly Report. For further information, questions or help, check our website or contact us at

anschaef Tue, 01/30/2024 - 11:03 Byline Computer Security team Publication Date Tue, 01/30/2024 - 11:00

CERN software to become central hub for EU research

Tue, 23/01/2024 - 10:49
CERN software to become central hub for EU research (Image: Zenodo)

What is the link between particle physics, the study of biodiversity and historical linguistics? The thirst for knowledge? Yes, but also the tool researchers are using to store all their findings and make them available to their peers: Zenodo. For more than ten years, this CERN-born data repository has been evolving to store scientific data for ever more research communities and to adapt to the needs of more scientific disciplines. Notably, it was a key player in the COVID-19 response, providing a platform for researchers to efficiently share results, data sets and software to help the international scientific community respond to the pandemic. Today, it is used by more than 8000 research organisations worldwide.

This success story is about to take an even more ambitious turn with a new project: HORIZON-ZEN. Since its inception in June 2023, it has become the latest in a series of projects funded by the European Union to make the data collected by European research more findable, accessible, interoperable and reusable (FAIR). Since 2021, making research data as FAIR as possible has become a requirement for all projects funded by the European Commission.

What does it mean to make data FAIR in practice? Today, this is still difficult for researchers to navigate, because FAIR are generic principles rather than verifiable criteria. “With HORIZON-ZEN, we are striving to make being FAIR simpler and more streamlined for researchers, and we are working with scientific communities to tailor Zenodo for their specific domain,” explains Lars Holm Nielsen, Section Leader in Open Science Repositories in CERN’s IT department.

As part of the project, Zenodo will be updated with a bespoke “European Commission” user interface. (Image: CERN)

Zenodo was born out of the need for a simple, easy-to-use storage solution for all types of research output: papers, theses, presentations, protocols, images, videos, data sets, software, etc. Generally, Zenodo is the ideal tool for researchers without a dedicated research infrastructure, for communities with a large network of institutes or for small institutes that have the necessary knowledge but not the tools. “Zenodo is the brainchild of the EU's open science policy. The European Commission has high hopes for this service, which could eventually become one of the EU's main repositories for research data,” Nielsen continues.

To make this possible, Nielsen and his team are putting a special, community-driven effort into the user experience, making it is easy for communities to customise their space, curate their content and build their online domain. “We are taking advantage of the 10 000 communities and the 300 currently running European-funded projects using Zenodo to co-design our tools. We encourage scientific communities to get a tailor-made Zenodo experience by becoming early adopters.”

Zenodo owes its success to the scientific community’s confidence in CERN, to ten years of continuous support by the European Commission and to the remarkable services provided by the tool. Above all, it is the result of the hard work of a small team at CERN who are eager to maximise the impact of CERN technologies.

The HORIZON-ZEN project is funded by the European Union under Grant Agreement No. 101122956.



ndinmore Tue, 01/23/2024 - 09:49 Byline Antoine Le Gall Publication Date Tue, 01/23/2024 - 09:39

BioDynaMo: cutting-edge software helps battle cancer

Tue, 16/01/2024 - 12:54
BioDynaMo: cutting-edge software helps battle cancer

Choosing the right cancer treatment is a massive undertaking involving multiple stages, high experimental complexity and significant costs. Currently, two main methods are used to find the best possible treatment solutions: in vitro testing and clinical trials. However, predicting the drug effects on each individual patient remains the Holy Grail of personalised medicine.

Born from CERN openlab in the CERN IT department, BioDynaMo is an innovative tool for “in silico” testing, i.e. experimentation carried out on a computer. Based on mathematical models, it creates and runs complex 3D computer simulations that help understand cancer progression and identify the most effective treatment strategies for specific tumour cases.

In a recent scientific publication, scientists affiliated with CERN, the Technical University of Munich and the University of Texas at Austin demonstrated the significant potential of advancing medical therapy with the help of BioDynaMo. The model successfully replicates medical data on recorded tumour growth and the effects of two anti-cancer drugs, Doxorubicin and Trastuzumab. By fitting the BioDynaMo models to the available pre-clinical data, scientists proved the platform’s ability to simulate different levels of efficacy of various drugs, treatment combinations and dosage regimens.

BioDynaMo is an open source project that strives to provide the most efficient and performant simulation platform for agent-based models. It accommodates a diverse range of use cases and can address research questions in oncology, neuroscience, epidemiology and many more disciplines. With its ability to simulate almost two billion agents (or cells), BioDynaMo is a powerful tool for analysing many different complex systems. Since 2015, BioDynaMo's consortium of scientists has been working on developing and optimising the engine, improving its performance and usability. For more information, click here.

The BioDynaMo project is funded with the support of CERN’s budget for knowledge transfer for the benefit of medical applications and of the CERN and Society Foundation. Find out how you can support the BioDynaMo project here.

ndinmore Tue, 01/16/2024 - 11:54 Byline Marina Banjac Publication Date Tue, 01/16/2024 - 11:43