Advancements in proton therapy cause for celebration

October 21, 2011 | 9:43 am

This article first appeared in Fermilab Today on Oct. 21, 2011.

In 1946, founding Fermilab director Robert Wilson was one of the first to tout the benefits of proton therapy. The cancer treatment has since been lauded as a way to minimize damage to healthy tissue while focusing a finely calibrated beam directly on the tumor – an impossibility for radiation treatments based on X-rays or gamma rays. Yet protons were not used within a hospital facility until 1990 with Fermilab’s construction of a particle accelerator at Loma Linda University Medical Center. Since then, the industry has grown and the technology has evolved. Worldwide, 37 centers use proton therapy and more than 73,000 patients have been treated.

The ProCure facility in nearby Warrenville, Ill., one of only nine centers in the U.S., is completing its first year of proton therapy. The facility uses an accelerator called the Cyclotron to administer the proton therapy. One distinction that sets the Cyclotron apart from other accelerators is that the particles are sped up to just 230 MeV, an energy high enough to treat tumors as deep as 32 cm within a patient.

The proton therapy process begins with the transformation of hydrogen gas into plasma. The Cyclotron speeds up the particles and isolates the protons along a curve of magnets that lead to one of four rooms within the treatment center. With the aesthetics of a set piece from “2001: A Space Odyssey,” a large gantry device rotates the beam line on a track and the patient, lying on a platform, is precisely positioned by a large robotic arm similar to ones used in automotive manufacturing. Here the proton beam is slowed to an energy that will reach the tumor and be absorbed by the cancer cells but go no further, while a brass aperture on the nozzle narrows the beam into the shape of the tumor. For the beam to be a precise match to the tumor, the aperture is designed for each individual patient.

Mingcheng Gao worked with DZero as the detector went operational and is thrilled to use the skills he gained at Fermilab as a senior medical physicist at the ProCure facility.

“The technology is advancing quickly,” he said.

The price of building and running each proton therapy center has been the field’s greatest hindrance for decades. After 22 months of construction, the ProCure center ultimately cost $150 million to build. Yet with the increasing demand for proton therapy, Gao sees proton treatments playing a larger role in fighting cancer.

“The cost will definitely go down in the future,” he said.

Brad Hooker

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Accelerator soup: Scientists to mix elements in LHC to study recipe for heavy-ion collisions

October 20, 2011 | 9:29 am

Superman may have superpowers, but Batman has the ingenuity to be just as heroic with the help of gadgets. Scientists at CERN are channeling the Dark Knight to try to make their biggest gadget, the Large Hadron Collider, perform a feat that counters its very design principles but may give them a better understanding of the early universe. They’ll have about 40 hours total to make it work.

Instead of colliding two beams of protons or two beams of much heavier lead ions, as the LHC usually does, operators will try to collide one of each in the coming weeks. On October 31, they will test the process for 16 hours, and two weeks later they’ll get another 24. That’s all the time they decided they could take from the precious month of data-collecting they will give the experiments during the upcoming lead-lead run. If it works, a proton-lead ion research program could be in place for November 2012.

The scientists undertaking the task of colliding protons and lead want to collect benchmark information about single beams of lead ions to get a better picture of what’s going on in lead-lead collisions. For that, the tiny proton acts as a probe of the more massive lead ion.

Theorist Urs Wiedemann explained that it’s a bit like making soup. A meticulous chef wants to know exactly what happens at each step of a recipe. This includes both the initial state of the individual ingredients – onions sautéed or raw? – as well as the final outcome inside the pot. Otherwise the chef can’t make informed changes. Similarly a physicist needs to know the individual properties of both of the elements he or she wants to collide, as well as what their smashing produces, in order to get the full picture for analysis.

After years of experiments, the quarks and gluons in the proton are well characterized; those in the lead ion are not. So, in a proton-lead ion collision, all unexpected effects can be attributed to the lead ion. With this knowledge, scientists will be able to make predictions about lead-lead collisions. “I can only test my theory of ion collisions if I know what is collided,” Wiedemann said. Colliding a proton with a heavy ion serves to “switch off the confounding factors,” he said.

Colliding protons and lead ions also gives scientists the potential to discover new physics phenomena, Wiedemann said. For this reason, all the experiments around the ring are interested in taking data during the collisions.

Scientists still need to test whether the technique will work in the LHC, said accelerator physicist John Jowett. The machine was built with a 2-in-1 magnet design: Both beams are controlled with the same magnetic field. This helps keep everything inside the ring symmetric when the beams inside match. Collisions and kicks, when one beam’s electromagnetic field pushes the other beam slightly off course, happen in the same place on each turn, a fundamental principle of stability for circular accelerators.

Protons and lead ions have different masses and charges, so they are not equally affected by the same magnetic field. The biggest challenges in this type of run are to inject and then control the beams as they ramp up from low to high energy. At lower energies, a beam of protons makes one extra lap around the LHC every 15 seconds. Since a proton beam makes about 11,000 laps per second, this discrepancy is small. But it is still enough to shift where the proton and lead-ion beams kick each other with every turn. As energy in the accelerator increases to its peak of 3.5 TeV and the beams get closer to light speed, however, relativity makes the 15 seconds stretch out little by little. At some point the difference between the beams becomes small enough that it can be overcome with a minor adjustment in their orbits – essentially the proton ends up going just a bit farther than the lead does, so they both take the same time to make one revolution.

To further complicate things, the more intense the beams get, the worse the effects each beam has on the other. The need to reach a certain level of intensity, roughly a measure of the amount of particles in a beam, puts a limit on how much data the experiments can extract. So, even if researchers can manage to inject two different beams in the accelerator, they will also need to make them with enough intensity for the method to be considered feasible.

The accelerator does have built-in flexibility despite having only one magnetic field: It has independent RF systems for each beam. These adjust electromagnetic frequencies inside a special cavity at one point around the ring, which controls each beams’ speed and orbit length. The LHC also has a powerful automatic feedback system that reacts to effects in the pipe by serving counter-kicks. This helps to keep the beams stable.

The LHC physicists plan to take baby steps – but fast ones, given the strict time constraints. First, they will simply try and inject two different elements into the LHC. If that works, they’ll try accelerating the beams. Only after that would they consider attempting actual proton-lead ion collisions.

“I hope it all works and we’re not prevented by mundane effects” such as a power outage, Jowett said. “In a month from now we should know the answer.”

Amy Dusto

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Mirrors harness X-rays for science

October 17, 2011 | 9:09 am

SLAC first published this article on Oct. 11, 2011.

Up close, they look simple as can be: a pair of metal bars, each with one side polished to a brilliant shine. One bar faces up, the other to one side.

They’re known as K-B mirrors, sophisticated X-ray focusing tools that have a pedigree going back to the very birth of X-ray microscopy. The shiny sides can be within a nanometer of being perfectly smooth, are exquisitely shaped into a barely perceptible curve of an ellipse, and may have one or more atomically precise coatings of exotic elements like platinum or rhodium.

The “B” in K-B mirrors stands for Albert Baez, father of folk singer Joan Baez, who helped invent this ingenious focusing system in the late 1940s while a graduate student at Stanford University. The “K” is for his Ph. D. advisor and co-inventor Paul Kirkpatrick, then head of the physics department.

Their invention signaled the beginning of X-ray optics – the ability to manipulate X-rays, an energetic, penetrating form of light. Today, thousands of scientists worldwide use X-ray beams to examine the material world in atom-by-atom detail, fueling advances in energy production, electronics, environmental cleanup, new materials, nanotechnology, medicine and many other fields.

“All these years later, K-B mirrors have become an essential tool for focusing X-rays to the tiny spots that scientists need for their experiments,” said Piero Pianetta, Stanford Synchrotron Radiation Lightsource deputy director. “Between SSRL and the Linac Coherent Light Source, we have about a dozen of these mirror systems here at SLAC.”  The world’s most accurate K-B mirror system currently in use, which was recently installed at LCLS, cost $1.2 million, when all of its alignment and stability aids are figured in.

For more than 50 years after Wilhelm Röntgen discovered X-rays in 1895, no one had figured out a way to focus this mysterious, penetrating form of light. Röntgen himself had proclaimed that it would be impossible to focus X-rays with lenses. In 1922, Arthur Compton reflected X-rays from polished surfaces at “grazing” or “glancing” angles of one degree or less. There matters sat for more than two decades, when Kirkpatrick began to explore the possibility of using Compton’s technique to focus X-rays.

Reflecting light with a single curved mirror produces a severe astigmatism, focusing rays from a point source to a line. “It was Kirkpatrick’s idea that a second curved mirror placed at a right angle to the first would ‘squeeze’ that line down to a point,” Baez said later in several retrospective articles and talks. He had been teaching calculus at Stanford and also working as a lab assistant in the Physics Department when Kirkpatrick asked if he’d like to work under him as a graduate student to develop this idea.

“I jumped at the chance,” Baez recalled.

In a historic 1948 paper, Kirkpatrick and Baez introduced their mirror pair as part of the world’s first X-ray microscope. But it would be another quarter century before three other developments enabled scientists to use the mirrors productively: In the mid-1970s, machining, polishing and metal-coating techniques improved enough to make ultra-smooth surfaces that could reflect X-rays without significant scattering. Second, James Underwood, an X-ray optics pioneer who later worked at Stanford, showed how to flex the mirrors precisely into the elliptical shapes that eliminated unwanted optical aberrations. Thirdly, new X-ray sources called synchrotrons produced intense beams of X-rays for probing and unlocking the secrets of molecules and materials.

With more than 70 synchrotron light sources now operating or under construction around the world, K-B mirrors are made by six manufacturers: two in France and one each in Germany, Japan, the United Kingdom and United States. There are several other ways to focus X-rays, but these mirrors are popular because unlike technologies based on diffraction or refraction, they reflect most  X-ray energies approximately uniformly.

Despite their simple design, crafting K-B mirrors has become much more complicated over the years. The first K-B mirrors were made of glass or quartz coated with a reflective metal film. Today’s mirrors are typically made from silicon crystals polished to near-atomic smoothness and then coated with ultra-thin layers of hard silicon carbide or dense metals. The shorter the X-ray wavelength being focused, the more precise the mirror surface must be.

“The mantra for X-ray mirror designers is ‘figure and finish,’” said Underwood. “Figure is the shape of the mirror and finish is its surface roughness. Many innovations over the years have improved our ability to make more accurate focusing figures and smoother mirror finishes.”

The mirror surface must be formed – or flexed – into the correct curved shape to focus the beam. This can be done in several ways. Most often, the mirror surface is polished while flat and then positioned in the beamline, supported on both ends. Then, an actuator motor applies a bending force near each end of the mirror, flexing the mirror into an ever-so-slight concave shape. Controlling the placement and amount of the force, as well as the mirror block’s shape and its supports, determines the resulting curve.

“For point-to-point focus you need an elliptical mirror shape,” said SSRL engineering physicist Tom Rabedeau. “Focusing a collimated beam to a point or vice versa requires a parabolic mirror shape.”

The mirror has to keep that shape despite being pummeled with intense high-energy X-rays. Although the X-rays are supposed to reflect off the mirror at a glancing angle, some of their energy is inevitably absorbed by the mirror, and the resulting heat buildup can warp or otherwise distort it.

The high energies of the X-ray laser pulses at the LCLS can also cause ablation, ejecting atoms from the mirror surface and reducing focus quality. Coatings can help minimize such damage. And while the mirrors are usually held in a vacuum, stray molecules owing to imperfect vacuum may stick to the mirror surface,  degrading its focus.

Temperature fluctuations can deflect the mirrors’ focal point. And when using long mirrors, designers even have to account for sagging between the mirror’s end supports due to gravity, said Nicholas Kelez, LCLS mechanical engineer. Jitter in the actual location of the X-ray beam also affects its ultimate focus.

“K-B optics are nice, since you can adjust one axis at a time,” Rabedeau said. But even a tiny error in the adjustment can throw the beam’s focus way off. For a one-meter-long mirror, “a one-micron mirror deflection means a huge 60-micron move in the focus spot 30 meters distant,” he added. Increasingly, researchers are using automatic sensor-feedback “servo” controls to fine-tune the positions of the mirrors to keep the X-rays focused accurately onto their target.

“All in all, K-B mirrors give you much better control of the focused spot shape than other X-ray focusing methods,” said Dan Harrington, SSRL engineering physicist.

The world’s best K-B mirror system currently in use is in LCLS’ Coherent X-ray Imaging (CXI). Its $300,000 mirrors were made in Japan using a precision liquid-jet method to shape the desired elliptical figure directly into the silicon, avoiding the need for mirror-bending apparatus. Each of the 350 mm-long reflecting surfaces are smooth to better than 1 nanometer surface roughness over their entire length.

A German company then built the mirrors’ enclosure, alignment system and 6-ton granite base, bringing the total price tag of $1.2 million. It can focus to a one-micron spot, and its focal plane can be moved by about half a meter to accommodate the needs of various experiments, said Sebastien Boutet, CXI instrument scientist.

CXI’s current K-B system won’t be the star of the show very much longer, however. A near-twin of that system, designed to focus the LCLS pulses down to much smaller 0.1-micron-diameter spots, has been built in Japan and is being commissioned now in Germany. Installation should begin at CXI next month.

- Mike Ross

 

Guest author

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Tevatron operations: A way of life

September 30, 2011 | 10:38 am

Editor’s note: This afternoon, Sept. 30, Fermilab will shut down the Tevatron for the last time. A broadcast of the event will begin at 2 p.m. CDT and will be available online. Fermilab Director Pier Oddone will host the broadcast, which will feature the shutdown in the Main Control Room, and the CDF and DZero control rooms. Fermilab Today published this story to honor the operators – the men and women who have kept the accelerators running 24 hours a day, seven days a week, 365 days a year.

A steady, consistent beep is the soundtrack of the Main Control Room in Fermilab’s accelerator complex. The metronomic resonance, not unlike a submarine, is reassuring to those who know it best: The operators. The regular tone signals that all is well with the 10 accelerators maintained, and often improved, by the Accelerator Division at Fermilab. But when the monotonous pitch is interrupted by any one of several alerts, the operators leap into action – even in the middle of the night.

Operators – the men and women who keep the accelerators running – work 24 hours a day, seven days a week, 365 days a year. Four crews rotate through three shifts every weekday, with two 12-hour shifts on Saturday and Sunday. The weekday shifts are split into day, evening and owl. Every shift is different.

At the basic understanding of their job, operators run the accelerators. But it goes further than that. Not only do they send beam to whichever experiment needs it at the moment, they also provide constant care for the accelerators. The accelerators can be brought down by storms, heat, electrical surges and even frogs.

Operators work in unique conditions. They’re often the first to know that there’s a problem with an accelerator, and they’re often the first to propose a solution.

“We’re the first line of defense, the skin,” Duane Newhart, the Deputy Head of Accelerator Operations, said. “We have to logically respond to problems, while dealing with a variety of personalities, often in the middle of the night.”

In the 15 years that Newhart has worked in Operations at Fermilab, he said not a day has been the same. He recalled how one operator handled a particularly difficult mystery.

“Duane Plant once investigated this TeV ramp trip that kept happening, but it’d move forward 3 to 5 minutes every week,” Newhart said.

Plant found that a service van would drive by around that time. The sun reflected off of the van’s windows, bounced to the service building, hit the photocell on the dump switch, and then the switch would open, causing the ramp to trip off.

“Not only is it amazing to see how people solve these problems, but it’s also incredible to see all of these different people working together,” said Michael Backfish, Operator II. “I’ve seen people on all sides work together for science.”

The pressure can be intense, but the operators know how to alleviate their stress with a little good-natured fun.

“We played a few practical jokes back in the day,” Paul Czarapata, the Deputy Division Head and former Meson Crew Chief, said. “There was a tech who was crazy about keeping his tools secure and had a desk with an elaborate locking mechanism.”

One day, several operators jimmied the lock, removed the tools and put on innocent faces.

“The guy was flustered,” Czarapata said. “He thought it was funny, too, once we pointed out his tools sitting safely in the corner.”

They have fun playing pranks on each other, but the operators can become very serious, very quickly.

“We have fun, but it just takes one alarm to make everyone focus,” Newhart said. “We go from laughing to serious in a second.”

Despite the strange hours and unpredictable work day, or in some cases it’s because of these things, there’s an excitement in operations.

“You get to watch what happen,” said Bob Mau, the former Operations Department head. He’s now retired. “You get to go everywhere and see a little bit of everything.”

All of that on-the-job training gives operators exposure to the rest of the laboratory and the variety of jobs therein. Mau said that a former operator can be found in nearly every division and section.

“Most operators are hired right out of school. They’re trying to figure out what they want to do,” Mau said. “In operations, they learn the complex. It’s a great spring board for people to find what they’re really interested in.”

Regardless of where they end up, operations becomes a part of who they are.

On July 23, hundreds of Fermilab operators gathered to celebrate the 40th anniversary of Operations. Current employees, retirees and their spouses and children shared stories over a potluck picnic and barbeque. “There are people here that I haven’t seen in 15 or 20 years,” Mau said. “It’s nice to see that these people thought enough of their early jobs to travel all this way.”

“In operations, you become a bit of a family,” Jim Morgan, an engineering physicist, said. “Everyone is always in each other’s face, and we take all of the good and all of the bad. We’re close.”

There are often differences that need to be navigated, but operators are tied together in pursuit of the common goal to make the accelerators work.

“Operations is our opportunity to contribute to something bigger,” Dave Capista, an engineering physicist with the Main Injector Department, said. “It’s our chance to contribute to science.”

Ashley WennersHerron

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Fermilab’s Antiproton Source: A rich history and an exciting future

September 29, 2011 | 1:04 pm

Fermilab Today first published this story on Sept. 29, 2011.

Fermilab’s Antiproton Source has long produced the antimatter that makes Fermilab’s particle collisions possible. While the Antiproton Source will shut down along with the Tevatron on Sept. 30, there are plans for its future.

The facility that houses the Antiproton Source will be reconfigured for two proposed experiments: Muon g-2 and Mu2e. Instead of creating antiprotons, both experiments will use the reconfigured facility to generate intense muon beams. While each would produce exciting and interesting data, they are both very different from the Antiproton Source’s original mission.

Fermilab’s Antiproton Source came out of an upgraded design of a similar machine that was housed at CERN.

Fermilab’s first antiprotons were produced in the Tevatron’s first collider run in 1988. At that time, it took more than an hour to make 10¹⁰ antiprotons. Now, the Antiproton Source can make 30×10¹⁰antiprotons an hour.

“The antiproton production rate in those early days now seems like an incredibly slow pace,” said Steve Werkema, deputy head of the Antiproton Source. “I think we would’ve been amazed by the production number now.”

The Antiproton Source was upgraded in the mid-1990s, before collider Run II. Improved accelerator optics and upgraded stochastic cooling systems aided in the jump of antiproton production. The rate of antiprotons produced jumped significantly during this time, due to the combined efforts of improved accelerator complex components.

“We really have to recognizethe efforts by the operators,” Werkema said. “There are long periods of routine running, and the operators are not happy to merely sit and watch the beam. They get to work tuning the machine. I think a good part of the improvements are due to the amazing things they’ve done.”

More than tuning is necessary to convert the Antiproton Source facility into an area appropriately equipped to house the Muon g-2 and Mu2e experiments. Fermilab’s muon program is a strong component of the laboratory’s new direction. The laboratory will use muon beams to study fundamental laws of physics. Both of these experiments are possible, in large part, because of the cost savings that comes from reusing the Antiproton Source infrastructure.

These muon experiments will be at the cutting-edge of high-energy physics for Fermilab’s push into the Intensity Frontier in the coming decade. Both experiments are currently in their design stage, with scientists and engineers finalizing conceptual designs. Muon g-2, the smaller of the two experiments, is aiming to start construction in 2013 and begin taking data in early 2016. Mu2e expects to finalize their conceptual design this year and is working toward a construction period that would allow for data production toward the end of the decade.

“There’s a lot of work to do moving forward,” Werkema said. “We’re sad to see the Antiproton Source go, but we’re going to be busy.”

Muon g-2 is the newest generation of a similar experiment performed at Brookhaven National Laboratory in 2001, which found a disagreement in the data value and the Standard Model prediction of the gyromagnetic ratio “g” of the muon.

“We’re doing the same type of experiment, but with higher precision,” said Chris Polly, project manager for Muon g-2. “The Antiproton Source infrastructure plays a key role in getting to that higher precision. By building a 1,000 meter long beam line at Fermilab, the muon beam will have a much higher quality than what could be achieved with the 80 meter beamline used at Brookhaven.”

The Antiproton Source was not designed to employ the high beam intensities needed for these experiments. However, the scientists see a lot of potential in the current facility.

“The Antiproton Source rings makes Fermilab the ideal place to do the Mu2e experiment,” said Bob Bernstein, the Mu2e co-spokesperson. “Their length happens to be just right for our physics needs.”

The Mu2e experiment will increase the intensity of muons stopping in their target by four orders of magnitude over any prior experiment. The discovery potential and the techniques developed for Mu2e will pave the way for future possibilities with Project X, a proposed high-intensity proton accelerator that would generate high-intensity beams for various experiments.

“Working with regular matter seems like it would be boring after making antiprotons, but, thankfully, it’s not,” Werkema said. “Both of these experiments come with unique and serious challenges. We won’t be bored.”

Ashley WennersHerron

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Keeping the Tevatron’s cool: A look back at electron cooling

September 13, 2011 | 2:58 pm

Fermilab Today published  this article on September 13, 2011.

When electron cooling was implemented at Fermilab in 2005, scientists thought it could help increase the peak luminosity by a factor of 1.5 to 2.

Now, less than a decade later, it has become integral to the Tevatron’s success, leading to an increase of instantaneous initial luminosity by nearly a factor of 3.

“The successful implementation of electron cooling has had a larger effect on the initial luminosity for the Tevatron than any other single improvement,” said Accelerator Division head Roger Dixon.

Electron cooling condensed the beam to make it easier to manipulate and accelerate, but it also encouraged adjustments to the entire accelerator complex, which was optimized to work well with the new system. It provided additional cooling beyond that carried out in the Accumulator, the accelerator that collects antiprotons, to the Recycler. This enabled the Accumulator to collect antiprotons at higher rates, which translated to more collisions.

“I would say that without electron cooling, the Tevatron wouldn’t be running now,” said Fermilab electron cooling pioneer and scientist Sergei Nagaitsev. “We wouldn’t have enough luminosity to sustain Run II.”

Getting to cool

Russian-born scientists Sergei Nagaitsev and Sasha Shemyakin worked on electron cooling as graduate students at the Institute of Nuclear Physics in Novosibirsk, Russia, where electron cooling was pioneered. Nagaitsev came to the laboratory in 1995 specifically to develop the Recycler electron cooling system. He knew the technology could work, just not exactly how to make it work at the high energies necessary for the Tevatron.

“Many people didn’t think that this scheme of high-energy electron cooling was possible,” Nagaitsev said.

While it seemed like a long shot to some, Nagaitsev spent 10 years leading a small team in designing, testing and then implementing the system. Part of that effort included developing a new beamline, cooling and solenoid technologies. They created a full-scale prototype at Fermilab’s Wideband lab and then, once they had operated a stable beam for 24 hours in 2004, moved it and reassembled it in its current home as part of the accelerator complex.

During the electron cooler commissioning, the team members worked shifts almost around the clock to get the system up and stable.

In the summer of 2005, the team had finally achieved a stable electron beam, and it produced nearly immediate results. On July 9, 2005, when experts were studying in parallel the cooler and a new procedure in the Recycler, they began to see a sharp peak in the antiproton momentum distribution – a clear indication of interaction between beams.

“Knowing that the system was working was one of the top moments in my life,” said Shemyakin, who was on shift that day.

Nagaitsev attributes the system’s success to determination and hard work, but also to intuition and a lot of trial and error.

“The executive decisions we made, even without a lot of information, turned out to be key to the entire project,” Nagaitsev said. “We didn’t know how important these decisions would be.”

For example, he explained, they decided to add a flange to the Pelletron, the 5 million volt electrostatic accelerator that prepares and dispenses electrons, hence dividing the pressure vessel in two halves. The standard version comes as a single cylindrical tank. That allowed them to lengthen it later, which was integral to making the process work.

Present run

Once the machine was commissioned, the team worked to improve and keep it at peak performance. However, similar to other machines at Fermilab that are custom-made and involve thousands of parts, electron cooling’s success is occasionally interrupted. When the electron cooling system is down, it affects the entire complex.

“We always welcome it back after the electron cooling crew finishes some critical repairs or maintenance,” said Paul Czarapata, deputy head of the Accelerator Division.

When something does go wrong, it falls to a dedicated group of individuals who work around the clock on getting the system back up. The group includes two scientists working full time on the system, Shemyakin and Lionel Prost, who have helped keep it running for the past 7 years. They love the challenge.

“In our business, if you feel that you are clever and can predict how something will behave, then you come to the control room and see that you’re wrong,” Shemyakin said. “The hardware really tests your abilities.”

Currently, thanks in part to the electron cooling system, the Tevatron is running better than ever, a situation that makes the shutdown of the Tevatron and the cooling system on Sept. 30 hard for many.

“I’ve worked with beams all of my life,” Shemyakin said. “It is interesting, and there are always new questions and new techniques to explore.”

Although Prost is looking forward to new projects, he is dedicated to making the electron cooling system run well until the very end. There are currently no plans for the system to be incorporated into other experiments, but Nagaitsev explained, there are always future possibilities.

When the system shuts down, Shemyakin and Prost will transition to working on the proposed Project X. The transition, they said, will be bitter sweet.

Rhianna Wisniewski

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