Cern Exclusive: Behind the Scenes With the LHC’s Control Centre Physicist

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By Lianna Brinded | December 4, 2012 12:53 AM EST

Life size replicator of CMS (Photo: Lianna Brinded)

The European Organization for Nuclear Research (Cern) provides a nucleus for global scientific discovery, and a nexus for the world's most daring and critical research. It is the birthplace of the worldwide web, and the epicentre of the ongoing search for the Higgs Boson particle, also dubbed the 'God Particle,' which could provide categorical proof of the origins of the universe.

Cern's newest facility, the Large Hadron Collider (LHC), will attempt to recreate in its experiments the conditions that prevailed in the universe during the split seconds after the Big Bang, in order to advance our understanding of the building blocks of matter. One of the first things it will do is to find out whether an elementary particle, the 'God particle,' exists or not.

The LHC is set in a 27km underground tunnel crossing the border between France and Switzerland near Geneva. Thousands of scientists, a succession of interconnected accelerators and a Super Computing Grid (SCG) are all working around this subterranean monolith to discover the elusive particle.

At the nerve centre of this gargantuan operation is Dr Barbara Holzer, an accelerator physicist in the Cern Control Centre (CCC).

The CCC combines the control rooms of the laboratory's eight accelerators, as well as the piloting of cryogenics and technical infrastructures, and is the epicentre of operations. It is manned 24 hours a day, seven days a week.

Speaking exclusively to IBTimes UK, Holzer took us on a journey through the importance of the project, the machines and the incredible life of a physicist at CERN. 

Barbara Holzer, accelerator physicist at CERN (Photo: Lianna Brinded)

Holzer completed her degrees and diplomas from the University of Technology Vienna and lives on the Suisse side of Cern, after securing a student placement at the lab.

When Holzer started to work on accelerators at Cern,  the Antiproton Decelerator (AD), the CCC or the LHC had not even been built.

"I worked on this machine for four or five years and I was there when we commissioned the machine; it was a very interesting time as that's where I learned accelerator physics. My education is in particle physics and my time at Cern before working in accelerator physics has been in particle physics," she said.

The 46-year-old Proton Synchrotron (PS), which is the oldest accelerator in service at Cern in the CCC, prepares beams for the LHC while feeding the AD and other facilities with various particles, and is an integral part of the wider cycle as it decelerates particles in order to study it for a long time.

"It takes something like a minute for one cycle to go through and what's happening is that when the protons hit the target (the protons come from another machine), a whole bunch of other particles and among them the anti-protons are produced. They are then trapped by a magnetic horn and are then fed into the vacuum chamber of the anti-proton decelerator, which is big because the particles have a big spread," said Holzer.

"This magnetic cycle also shows you the energy of the particles. In contrast to the other machines, the particles get decelerated because we want to use the anti-protons very slow. People even trap them in magnetic traps and they can study the same particle for a long time. It's a tricky process and that's why it takes so long," she said when talking about beam cooling and deceleration.

However, after first being placed on the AD, she moved from particle physics to accelerator physics.

"I have my degrees and diplomas from the University of Technology in Vienna but I did my PhD and my diploma thesis here at Cern. So I was here on a student placement and worked on a high energy experiment. I became really intrigued by the accelerators and after my PhD, I changed to accelerator physics," she said

"Changing disciplines doesn't happen that often, but it does happen. We have a few colleagues in accelerator physics that started out as particle physicists. If you saw the beauty in the machines, then you'd understand why we changed over," she added.

The LHC Control Centre (Photo: Lianna Brinded)

Being in the nerve centre for the LHC, her career has notably encompassed most of the disciplines and projects that make up the CCC.

After working on the AD, she moved through a number of other areas, which highlighted the diverse number of skills physicists needed to work in the nerve centre, which has 39 control consoles.

"In between moving over to another one of the projects, I worked on some studies and a machine that is still in the study phase. I also worked on electron cooling for a year, which is actually one of the cooling techniques in the AD. I also worked on a cooling technique for this machine study, called the 'Neutrino Factory' but it has not been demonstrated yet, so it is all theoretical work. At the moment there is an experiment going on trying to demonstrate it," she said.

"And then afterwards I worked on Beam Loss Monitoring (BLM) for the LHC. You have to be very careful how many particles you lose out of your beam because they can damage your equipment and at the LHC, it is full of super conducting magnets and only a small amount of heat into a super conducting magnet can cause a quench (that is when a superconducting magnet changes into the state of normal conduction, resulting in an abnormal termination of magnetism). This could lead to the machine being stopped and for the magnet to be cooled again and that takes a long time and so we absolutely want to avoid that. So this is why the machine protection, and beam loss monitoring is so important and to know exactly how and how many particles are lost."

With some 13 operators working on any one shift, not counting the many experts responsible for assisting them, 3600 monitors are in use on the project, and each of them can abort the beam in the LHC. However, despite the huge role played by artificial intelligence, Barbara, who spent years helping to create the abort thresholds, notes how important the human element is to the entire operation.

"You can't really write a computer programme that tells you the right answers. Although you need to use a lot of computer programmes, in the end the judgement is on the human and that makes it difficult. You can make errors, so we always have two people cross-checking the data to get it right," she said.

Barbara Holzer in the LHC Control Centre (Photo: Lianna Brinded)

The symbiotic nature of tasks being completed, projects being created and maintained, as well data being processed at any given second, certainly raises a huge number of challenges along the way.

However, indicative of how people pose more of a hurdle than machines, one of Barbara's most tricky challenges has actually been in the human side of project management rather than even the hugely challenging technical aspects.

"Every project has its own challenge but after a while you figure out how to deal with that. For example when I was responsible for the design of these beamloss monitors, we needed mass production and at that stage, I was responsible for the mass production. I had not supervised a lot of people before that and now I had to make sure that everyone was doing what I wanted, what I needed them to do and kept to the schedule and that the rights things were delivered. At the beginning I found it difficult, but after a year it was really easy. It's a learning process," said Barbara.

"I was not much in the control room the week leading up to the LHC being switched on but for me it was quiet because we had installed our system (the BLM system), the thresholds and checked them, so we continued to check. The machine was closed, so we couldn't go into the machine anyway, all was done and prepared.

"However, it is not like we go from 0-100; the [beamloss monitors] came on in stages. As the beam intensity was increased gradually, also the protection level only needed to be increased in stages. So how tight we set the protection came on in stages and the stages lasted over half a year. The switching on of the LHC was calm, everything was prepared very well in advance and checked thoroughly before switching on the machine. There was no panic or no last minute actions," she added.

No one day is the same for physicists at Cern. For Holzer, days can start exceptionally early in order to prepare for the 0830 CET presentations, which requires hours of sifting through the night's data logs and notes from colleagues. Furthermore, determining who is working on what tasks for the day also takes time.

"Every day is different but if you are in coordination, 12 hours isn't unheard of but then we only do it for one week and then have a break. It really depends what's happening with the machine and if everything is going fine then of course," she said.

In addition, like a number of other physicists, Holzer teaches a number of students placed at CERN, who will be the next influx of bright minds to the lab.

Cern's super computing grid (Photo: Cern)

Cern is not just about discovery, it is also about creation.

With the nurturing and development of the next generation of scientists and the innovation of society-changing technology, such as the web and now the SCG, Cern is at the forefront of R&D. As with most of the inventions from Cern, the original innovative equipment, techniques or discoveries have a positive consumer knock-on effect years down the line.

"Like the web, it wasn't intended like that but just look at how it changed my life, my work life, my personal life, all our lives!  I find it amazing because when I was a student at university, when you wanted to find some literature, you had to go to the library and just hope they have what you want. However, now we just type it in and find the paper what you want. In Japan they are scanning a lot of old papers, so you can even find 50-year-old papers in a database in Japan."

Holzer notes that there are a number of inventions or discoveries at Cern that will have a positive effect on wider society in about a decade's time.

"The Computing Grid and cloud computing and large scale data analysis will make an impact on consumer society in years to come. Also medical equipment will continue to profit from Cern developments, such as particle detectors, like crystal scintillating detectors for PET scanners or wire chambers for radiography.  Then of course cancer treatment facilities, with proton and ion therapies, where more and more facilities are being built and this is very much on the cutting edge of science," she enthuses.

"There is currently a project to test ions for cancer treatment, which is not so much used in cancer therapy just yet, as there is no complete validation what ions or what beam characteristics to use; beam energy is given by tumour location. For example, how intense the ion beams should be as biologically there is a different effect if you deliver the same dose in a short time or a long time and there is an investigation into whether there could be a facility at Cern to study these effects systematically and to link more to medical people to study the biological effect."

With current European Commission (EC) chiefs looking to slash science and innovation budgets across the board to buoy the flagging European economy, scientists, including the Cern director general, have voiced concerns over what it will mean for economic recovery.

As with most of the physicists at Cern, Barbara highlighted the wide impact technology and innovation created at the lab has on industry and wider society, and one particular story brought this home.

"Some 10-15 years ago in Japan when the economy was first sinking into a recession, I was working with a lot with people from Japanese institutes. Once I went there for work but in a central park there were lots of people living in the park in tents because of the recession and I was really shocked. However at the same time, Japan was always pouring money into fundamental science, as well as applied science, and the government was still granting scholarships and funding for big experiments and accelerator complexes because they strongly believe that by doing that they would help their industry and bring the country out of recession," she said.

"When you look at the budget of Cern, a lot goes back into the industry in a variety of ways. We buy components to make the machines, the infrastructure, the maintenance of the networks and we collaborate with industry to invent and bring new technology to the wider world. For example, we needed certain complex cables to deliver very small signals over long distances without accumulating noise and with a company we developed this and of course paid for it. In turn, the company has Cern technology and can sell on the product in the wider industry. Unfortunately, we  also have a big electricity bill!"

With such a diversity of projects and potential in a Cern physicist's career path, it's a wonder that they are able to have any free time at all. However Holzer told us that, despite the number of tasks and servicing her hectic career, she always finds time for social life.

"It is very important for me to have personal life and I have a lot of interests that are connected to vitality. I like cooking, gardening and yoga and it is very important to me to move enough. I also did tai chi and pilates and on the weekends I cycle with my husband on an electric bike on his 60 km bike rides," said Barbara.

But what does the future hold for Holzer and what would she do if she wasn't working at Cern?

"It's so difficult to predict how the future will pan out as because after every project I move onto another one that is always just as fascinating as the last. For instance, when one project was becoming less time consuming, I became really interested in the coordination side and after asking to do it, I was amazed that within only two months I was actually doing it," she said.

"If I wasn't an accelerator physicist, there are so many areas that I have always been interested in, such as alternative technologies, energy saving in the building industry, when I was a student not much was going on in the building sector but now there are lots of developments. Fluid dynamics also fascinated me because of the beautiful mathematics," she said.

For the latest coverage on Cern, don't forget to check out our special coverage:

CERN and Science Budget Cuts Are Bad for EU Economic Recovery

CERN: LHC Behind-The-Scenes [SLIDESHOW]  

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