The U.S. Department of Energy's Thomas Jefferson National Accelerator Facility
Jefferson Lab Perfects a Crab for Argonne National Lab
The Chesapeake Bay is known for its blue crabs, but it's never seen a crab like this. A new prototype device, called a crab cavity, has been developed and built by Jefferson Lab scientists and engineers in collaboration with Argonne National Lab. The crab cavity is being developed to upgrade the experimental capabilities of Argonne's Advanced Photon Source.
John Mammosser is leading the Jefferson Lab effort on the crab cavity project. The staff engineer says the cavity is built with the same technology that powers the lab's two accelerators: superconducting radiofrequency technology. But that's about where the similarities end."It's very small and compact: this cavity has features that we've never had to deal with before. It has a very unique design and really is stretching our abilities in a lot of ways," he says....... more
Lab to Mark the End of CEBAF 6 GeV Operations
Jefferson Lab will officially end 6 GeV operations of the Continuous Electron Beam Accelerator Facility during a short ceremony planned for Friday, May 18.....more
Distinguished HU Professor Joins Lab as Hall Leader
Cynthia Keppel, a Hampton University experimental physicist and winner of the 2011 Virginia Outstanding Scientist Award, has been named Jefferson Lab's Group Leader of Experimental Hall A......more
Users Group Represents Scientists Conducting Research at Lab
Sebastian Kuhn, chair of the Jefferson Lab Users Group Board of Directors, is a man with a message.....more
The Chesapeake Bay is known for its blue crabs, but it's never seen a crab like this. A new prototype device, called a crab cavity, has been developed and built by Jefferson Lab scientists and engineers in collaboration with Argonne National Lab. The crab cavity is being developed to upgrade the experimental capabilities of Argonne's Advanced Photon Source.
John Mammosser is leading the Jefferson Lab effort on the crab cavity project. The staff engineer says the cavity is built with the same technology that powers the lab's two accelerators: superconducting radiofrequency technology. But that's about where the similarities end.
"It's very small and compact: this cavity has features that we've never had to deal with before. It has a very unique design and really is stretching our abilities in a lot of ways," he says.
The crab cavity is a key feature in Argonne's bid to upgrade its Advanced Photon Source. The APS is a synchrotron – a circular accelerator – that provides the brightest X-ray beams in the Western Hemisphere to more than 5,000 scientists for experiments in nearly every scientific discipline, from materials science to biology, chemistry, environmental and planetary science, and fundamental physics.
If successful, the crab cavity will add a valuable capability to the APS.
"It takes the beam that is coming through and spreads it out in energy – it gives it a kick to chirp the beam. They then take energy slices of the beam and create a short, pulsed X-ray," Mammosser explains. "They're looking at short X-ray pulses to explore materials. In materials science, short pulsed X-rays are becoming the path forward to studying interior interactions of atoms."
The chirping of the beam is provided by the small cavity's very unique and complicated shape. No one has ever made a cavity to the specifications that the APS requires, and the shape made the cavity very difficult to manufacture. Unlike most niobium accelerator cavities, which are made by manipulating a sheet of metal niobium into the correct shape, a different process was needed to build the crab cavity.
"The size and features and shape of the cavity are very intricate," Mammoser says. "We decided that the best way to achieve the tolerances that need to be put into it was to machine it out of a block of niobium. This is the first time, that I know of, that a cavity of this type has been fully machined like this."
Each half of the cavity was machined out of a block of solid niobium. The niobium was a large-grain variety, which means that the crystalline niobium block was made of easily identifiable large crystals of niobium. The two cavity halves were welded together with a beam of electrons in an electron-beam welding machine to make a single cavity.
"It's a very odd shape, and this really stretched the e-beam welder, Bill Clemens' abilities. He was able to program the machine to follow the contours of the cell, and he did the full welding of the two cell halves with waveguides in one shot."
In all, the team produced and tested nine different cavity prototypes. The final shape of the prototype has now been selected.
The team has built three cavities in the final prototype shape. The two best cavities will each be assembled into an accelerator unit, called a cryomodule. Like all accelerator cavities built with superconducting radiofrequency technology, these cavities need to be kept at just a few degrees above zero to function properly. APS will purchase a new refrigeration system to cool the cavities, and the cryomodules will insulate the cavities during operation to help keep them cold.
The test cryomodule will be ready for installation and first testing in the APS in October 2013. "There are two requirements: one is the requirement for the cavities to operate and chirp the beam. The other is for the cavities to not disturb the beam when they're not being operated, so that the APS operators can turn on an experiment and turn it off, and it has no effect on beam going through," Mammosser says.
Following successful testing of the test cryomodule and pending approvals, the team will then move forward with building two complete cryomodules to be installed in the APS.
"They need four cavities in each one, and there will be two cryomodules – one to chirp the beam and one to un-chirp the beam," he says.
Mammosser says the team owes the successful manufacture of the challenging design to the dedicated Jefferson Lab staff.
"I think the Machine Shop just did a fantastic job. They paid attention to all the details, and they really did a great job in fabricating all the parts. And when you see this, it's really a piece of artwork. So we really need to give them kudos," he adds.
It's hoped that projects like this one will usher in a new tool in a budding scientific discipline, called control science. The idea of control science is that observing and gaining understanding of the interactions among atoms and molecules that determine material properties and processes will one day allow us to begin directing those interactions and controlling the outcomes on a molecule-by-molecule and atom-by-atom basis.
It could be that control science will one day make use of the decades of research that have led to our understanding of the properties of the atom's constituents, such as the research here at Jefferson Lab, leading to new materials and processes that will directly benefit society.
By Kandice Carter
Senior members of lab leadership, Department of Energy managers, and representatives of the lab's 1,300-plus visiting scientists (user community) will gather at the CEBAF control room for the event.
After comments from lab leadership to mark the end of 6 GeV (billion electron volt) operations, the on-duty accelerator operations crew will pass the controls to the team that was working on May 25, 1995, when the 4 GeV electron beam hit the target in Hall C (the first experiment hall to receive 4 GeV continuous-wave electron beam and the first hall used to carry out an experiment). The crew that day included, then Crew Chief Bob Legg, Operators Mike Spata and Noel Okay, and Program Deputy Reza Kazimi.
Since beginning operations, more than 175 experiments have been conducted using CEBAF. And more than 400 doctoral degrees have been awarded, based on research conducted at the lab.
Jefferson Lab Director Hugh Montgomery will terminate 6 GeV beam for the last time followed by Andrew Hutton, Accelerator Division associate director, and Arne Freyberger, Accelerator Division director of operations, turning off the superconducting radiofrequency zones in the two linear accelerators in CEBAF.While the event marks the official end of 6 GeV CEBAF operations, it sets the stage for a new era – the 12 GeV era that is already underway. While the running of physics experiments won't resume until 2015, the site will be humming with activity as it undergoes a major upgrade.
The project, dubbed the 12 GeV Upgrade, will deliver electron beams of up to 12 GeV to the new experimental Hall D, and beams up to 11 GeV to Halls A, B and C. Upgraded and new equipment will be installed in the existing halls to expand the research capabilities available to researchers.
Jefferson Lab's users community, the researchers who conduct basic nuclear physics experiments with CEBAF, numbers more than 1,300. They come to Jefferson Lab from 40 nations and represent more than 200 institutions.
Due to limited space in the Machine Control Center, the shutdown event will be streamed live and video recorded.
To celebrate the 6 GeV era, an event for all lab staff, users and students is being planned for Wednesday, June 6, from 3:30 – 6 p.m. Event details will be available in the coming weeks.
Cynthia Keppel, a Hampton University experimental physicist and winner of the 2011 Virginia Outstanding Scientist Award, has been named Jefferson Lab's Group Leader of Experimental Hall A.
Keppel has been a professor at Hampton University since 1995 while also holding a joint appointment as a staff scientist at Jefferson Lab. Her research interests include experimental nuclear physics, nucleon structure, medical instrumentation, proton radiotherapy and medical physics. At Jefferson Lab, Keppel and the HU experimental nuclear physics group have done electron scattering experiments to study the fundamental structure of protons and neutrons. She has been the spokesperson for more than a dozen experiments and co-authored 190 peer-reviewed publications. She is also an active member of the Coordinated Theoretical-Experimental Project on Quantum Chromodynamics (CTEQ).
"We are extremely pleased that Thia has agreed to join Jefferson Lab as a Group Leader," said Lab Director Hugh Montgomery. "She's an outstanding scientist, teacher and leader, qualities that were key in our worldwide search. She will have a central role as we prepare to double the power of our accelerator to 12 GeV and embark on a new era of experimentation in pursuit of our mission to learn more about the nuclear structure of the visible universe."
"Thia Keppel's merits, in both science and management, speak for themselves," added Rolf Ent, associate director for experimental physics. "We are fortunate to have her accept the Hall A leader position, with exciting scientific prospects. I would like to also acknowledge the work of the search committee chaired by Bob McKeown (deputy director, Science and Technology, Jefferson Lab) and Don Geesaman (associate director, Physics Division, Argonne National Laboratory), who performed an extensive and worldwide search."
At Hampton University, Keppel was involved in the development of medical applications of nuclear physics. She founded the HU Center for Advanced Medical Instrumentation (CAMI), where researchers concentrate on technology development for nuclear medicine, radiation therapy and other medical applications. Her work at CAMI resulted in seven awarded and six pending patents.
She also served as the scientific and technical director of the Hampton University Proton Therapy Institute (HUPTI). Additionally, she established and co-directed the HU joint medical physics program with the Eastern Virginia Medical School, the first medical physics program in Virginia and the only one at a historically black college.Keppel received a bachelor's degree from Saint John's College in Annapolis, MD, and a master's degree and Ph.D. from The American University in Washington, DC in 1995.
Sebastian Kuhn, chair of the Jefferson Lab Users Group Board of Directors, is a man with a message: If you're doing research at Jefferson Lab, the Users Group is your source of information and your voice.
"We are trying to offer some organization to the users to make their research experience here more enjoyable and productive," Kuhn explains.
As a first, practical step, Kuhn encourages every user to sign up for the "CUGA" email list and be sure that its messages are getting through. The information in the emails, generated by UG Secretary/Treasurer Lorelei Carlson, covers activities of the group and its Board of Directors, upcoming events, and timely lab announcements regarding everything from traffic and parking to severe weather warnings. Sometimes there's even a note about items that have been left behind. "While not every email is important for every user, it's always worth looking at," he emphasizes.
The Users Group's biggest event is its annual meeting and workshop, which will take place this year from June 4 – 6. The theme this year is "The end of the 6 GeV era at Jefferson Lab."
"We take stock of research at the lab and across the broader physics community," Kuhn explains. "We hear from lab management and the funding agencies about the lab's future. The agenda includes a poster contest for students, who can attend the annual meeting at no charge, thanks to the Jefferson Science Associates Initiatives Fund."
The cut-off date for abstracts for the poster competition, which offers first, second and third place prizes of $1,000, $500 and $250, is May 23. Graduate students are also invited to special lunch discussions to talk with physicists about the field.
The Users Group also holds two smaller gatherings each year, at the American Physical Society (APS) April meeting and the fall Division of Nuclear Physics (DNP) meeting in order to reach people who wouldn't necessarily come to Jefferson Lab. "These are outreach efforts to potential new users or people who want to know what's here and what's going on here," Kuhn adds.
Representing the Users Group is the UG Board of Directors (UGBoD). The board's work is intense and ongoing throughout the year, according to Kuhn. In addition to organizing the annual meeting, the group gathers twice a year with lab management and advises the JSA Programs Committee on the relative merits of user-generated proposals for annual program funds. It also selects winners for the annual postdoc and thesis prizes and its members are generally available and responsive to the hopes and concerns of the user community. During the past winter, the board also organized a "Users Town Meeting" (March 16) to discuss ideas for the future direction of the lab.
The five at-large members of UGBoD each focus on a particular sphere of interest: Quality of Life, Computing, Running Experiments and the Program Advisory Committee, Outreach, and Foreign Visitors. Three other members are devoted to specific constituencies: Theory, Postdocs and Graduate Students. These board members each serve a two-year term and half of the positions come up for election every year. Elections for this cycle ended May 6. This year, a successor to the chair was voted on; this position serves a total of four years – one as chair-elect, two as active chair, and one as past chair.
Two of the board's on-going concerns are the upcoming accelerator shut down, set to start on May 18, which will affect users in many ways; and the "severe threat to science funding, which is one particular reason we need to become more active," Kuhn says.
Many of the Users Group's programs and efforts are funded by the JSA Initiatives Fund Program, including the poster competition, thesis prizes, postdoc research grant, support for the annual Users Group meeting and for the DNP meetings, travel assistance for junior scientists to scientific conferences, etc. "We couldn't exist without JSA's support," Kuhn notes. "Each year they support many valuable activities that are not part of the lab's core purpose."
The board's current priority is to increase participation in the Users Group and at the annual meeting and workshop.
"As a researcher myself, I understand it's more fun to concentrate on my data," Kuhn acknowledges. "But if you rely on Jefferson Lab, you need to pay attention and get involved. The Users Group and its Board of Directors are only as effective as users are interested in what's going on."
For more information on the Users Group, visit: https://wiki.jlab.org/cugwiki
By Judi Tull
Jefferson Lab will hold an Open House on Saturday, May 19 between 9 a.m. and 3 p.m.
The event will include a number of firsts, including the first opportunity for the public to visit Jefferson Lab's newest experimental hall (Hall D), which is a cornerstone of the 12 GeV Upgrade project underway at the lab. The $310 million project, funded by the Department of Energy's Office of Science, will allow the lab to continue as a world leader in nuclear physics research. The project will provide new and enhanced research capabilities for the 1,360 scientists from 259 institutions that come to Jefferson Lab to conduct experiments or who use data from lab experiments. Ground was broken for Hall D in April 2009.
This event will also include the first opportunity for the public to visit the lab's new Technology and Engineering Development building. This state-of-the-art facility, which was built with some of the latest energy conservation and sustainability technologies, will provide research and work space for lab staff and visiting scientists.
Numerous exhibits, demonstrations, tours and hands-on activities are planned for the event and will offer opportunities for learning and fun for families and people of all ages. This year's theme "Passport to Science" will provide an interactive dimension that can be used by visitors of all ages as they travel around the lab.
Visitors will be able to see and hear about the lab's research program and its particle-acceleration capability (superconducting radiofrequency), a core capability for which there is growing interest in the U.S. and abroad. The lab's supercomputing and simulation capabilities will also be on display and the Free-Electron Laser Facility will be open.
Several local universities, museums, private companies and government agencies will present activities and information on complimentary scientific endeavors.
Special Presentations During the Day
The Open House will be free of charge and will be held rain or shine. Free public parking for the event will be available on the Jefferson Lab campus and adjacent property. Parking lots will open at 8:30 a.m. No early arrivals admitted. No vehicles will be admitted to the parking lots after 2 p.m. All parking will be accessible by turning east onto Hogan Drive at the intersection of Jefferson Avenue and Hogan, in Newport News. This intersection has a stoplight and Newport News Police will be on hand to direct traffic.
Visitors will be able to access the lab from 9 a.m. - 2 p.m. and stay until 3 p.m. The event is spread out over several facilities and involves a lot of walking, taking multiple flights of stairs and walking down and back up rough, inclined truck ramps. In some areas, visitors will be walking on compacted gravel or dirt surfaces instead of pavement. Wear sturdy, comfortable shoes and sunscreen or a brimmed hat and protective clothing. Free shuttle buses will be available to carry visitors between some of the tour stops, but marked areas may be traveled on foot. Photos and videotaping are welcome.
Vendors will be selling light refreshments. Jefferson Lab's last Open House was in May 2010. Jefferson Lab is located at 12000 Jefferson Ave. Newport News, Va. 23606.For more information about the event call 757-269-7100 or visit the open house webpage at: https://www.jlab.org/openhouse
Drawing upon years of research and technical knowledge, the national labs are taking on the critical task of making their unique facilities national models of sustainability.
To achieve this goal, leadership and staff at Jefferson Lab, and at the other national labs, are working to identify and implement best practices and innovative operations strategies to make facilities, and the larger Department of Energy research complex, more sustainable.
Sustainability is much more than acting environmentally "green." It encompasses a combination of economic, social and environmental elements that must balance to achieve a sustainable solution. Strategies that provide significant environmental benefit for instance, but are not economically feasible, or socially acceptable are not sustainable, according to Bill Mooney, the lab’s energy manager.
"In general, sustainable behavior encourages everyone at the lab, in our professional and personal activities, to systematically consider, in advance, the efficient utilization of all the resources we use, and how to reuse, recycle or correctly dispose of them after use," Mooney explains.
Federal legislation and various executive orders prescribe a specific set of diverse goals that define sustainability for the DOE and all federal agencies. A list of sustainability goals and Jefferson Lab's respective plans to achieve these goals over time is available in the lab's Site Sustainability Plan. The SSP considers a variety of sustainability initiatives that range from greenhouse gas reduction, to energy efficiency metrics, construction practices, waste management and water conservation. The SSP is updated annually. A copy of the current SSP, and additional information, including many useful links to DOE and EPA resources regarding sustainability, is available at https://www.jlab.org/sustainability.
"I would encourage all JLab staff to review the SSP to better understand the many areas of sustainability in which the lab is actively engaged," Mooney adds.
Jefferson Lab, as a community, has and continues to invest in a variety of efforts designed to improve the efficiency of certain operations, recycling, and purchasing products with recycled content. The lab also has strived to reduce waste, minimize energy consumption, and protect the environment from harmful materials or activities.
An important part of the lab's sustainability effort was creating a Sustainability and Environmental Management committee. The SEM committee has recently been chartered to support the development and implementation of sound sustainable practices throughout the lab, promote sustainability education and awareness, and oversee the lab's Environmental Management System. Membership in the SEM committee includes individuals from a cross section of lab organizations. Additional committee members, and/or interested participants in committee activities are always welcome.
To learn more about SEM committee plans, make suggestions, share ideas or ask questions regarding the lab's sustainability program, please contact Bill Mooney, ext. 5461 or email firstname.lastname@example.org.Learn more about the lab's sustainability program at: https://www.jlab.org/sustainability.
Jefferson Lab is a user facility; and over the years, people from nearly 90 countries have visited the lab or come here to conduct research, according to Sue Ewing, JLab Registration/International Services Administrator. Part of the JR/IS mission is to provide guests, visitors and international researchers with an organized, efficient transition into the lab while ensuring that the lab complies with Department of Energy contract rules as well as federal government rules and regulations for international visitors.
Ewing oversees the registration and approval process for all individuals not of U.S. citizenship coming to the lab. And to that end she is responsible for training and assisting the lab's administrative support staff and travel coordinators that help JLab hosts or sponsors who are responsible for initiating the registration process and the paperwork required to bring international visitors and researchers here.
"Hosts, administrative support staff and travel coordinators form the leading edge of JLab's visitor registration process," she explains. "The key to a successful visit for an international guest rests with the guest's JLab host. The registration process should be started well in advance of the visit date. The process needs to be done completely and notification of approval received by the visitor onsite date."
"JR/IS provides oversight, answers questions, and assists with troubleshooting glitches that could prevent a visitor from getting to the lab or send them home prematurely," she adds.
The paperwork is demanding and can be time consuming, she admits, and involves coordination and approval by a host of agencies, including the U.S. Department of State, the Department of Labor, customs and border patrol, Homeland Security, and U.S. embassies around the world.
"But, if a host contacts his or her division or work center admin. support staff or travel coordinator as soon as an invitation has been made, they can help the host with the process," Ewing notes.
When the on-line registration and training is followed, and the visitor provides the required documentation, the process goes smoothly and quickly, according to Ewing, and a guest arriving at the lab can receive an access badge and begin conducting research within a matter of hours.
A critical part of bringing individuals who aren't U.S. citizens to the lab requires the host to write a "Business Invitation Letter" to the visitor or new researcher. The letter provides the foreign visitor or researcher with critical information about the nature of the trip; and is required for the visitor to ensure entry to the U.S. with a Business Visa. The visitor or researcher must present the letter to U.S. Citizenship and Immigration Services officials at the U.S. Embassy and at the U.S. port-of-entry when they enter the U.S.
To make writing the Business Invitation Letter easier, the JR/IS staff has created a sample letter. The sample is available under Step 3 on the JR/IS Hosting Foreign Nationals web page at https://www.jlab.org/div_dept/admin/HR/jris/hosting.html
Ewing is available weekdays from 7 a.m. to 3:30 p.m.; and her assistant-in-training, Tara Wilkerson, is available weekdays until 5 p.m. to answer questions and provide guidance.
Wilkerson helps staff the Support Service Center reception desk (Bldg. 28, formerly called the VARC). She is an initial point of contact for all guests and visitors, and is involved in the registration, training and badging processes for everyone coming to the lab.
Ewing is very excited about bringing Wilkerson onboard the visa/immigration side of JR/IS. Ewing is currently training/mentoring her in all areas of visa and immigration. Wilkerson is now processing J-1 and H-1B visas and moving forward with becoming an expert in the complex world of immigration rules and regulations.
"I am very, very happy to have Tara onboard as a second person at the lab to concentrate on visa and immigration," Ewing said.
For more information about the international visitor registration process, and the services provided by JR/IS, visit its webpage at: http://www.jlab.org/hr/jris/
By Judi Tull
Here are the basic steps to take when you decide to invite an international researcher, guest speaker, job applicant, student or visitor to JLab.
Step 1: Host notifies department or division admin. support of the intent to invite a foreign national visitor/researcher to JLab and whether any type of JSA financial support or reimbursement is anticipated.
Mementos of the work she does are all around Sue Ewing's office in the Support Service Center: Russian nesting dolls, a scroll from Jerusalem, photos from all over the world. For the past decade, Ewing has staffed the Jefferson Lab Registration/International Services office – or JR/IS – the singular portal through which come all foreign visitors to the lab.
"I love this work," she said with a warm smile. "It can be challenging and sometimes stressful, but it is very rewarding and satisfying. It's nice to be part of giving someone a chance to contribute to the amazing research work accomplished here."
Ewing graduated with her master's in education in June 2011, following up on a bachelor's degree in business administration. "It's never too late for education," she commented.
She's also about to be certified as a nutrition consultant through the American Fitness Professionals Association, something she was spurred to do when she joined the YMCA and found lots of fitness advice, but little information on nutrition. With this certification, she'll be able to speak to school and civic groups about the importance of eating healthy.
Ewing's three grown children and seven grandchildren, ages 8 to 18, all live in the surrounding area. She shares her home with a two-year-old Havanese "ball of fluff" named Brinkley, who, she admitted, is spoiled. "He was asked to leave puppy pre-school," she added, "because he didn't want to obey the rules."
I was born in Nicosia, the capital of Cyprus, the oldest of four children. My dad was in construction and my mother stayed at home with us.
I went to public schools until high school when I was accepted into a special technical school that focused on physics, chemistry and the sciences. When I graduated, like all young men in my country, I was required to serve 26 months in the army. Since the island is small – only about three-fifths the size of Connecticut – even though I was away from home, I was never really very far. My duties in the army were varied: I was tasked with fixing weapons, working in stockrooms, even making sure the troops had enough potatoes for supper!
When I was finished with the army, I went to work as an electrical technician in a mill factory that made pasta. On weekends and vacations, I had the opportunity to travel throughout the Greek islands where I sailed and went scuba diving. I also toured Egypt. It was a very good life for a young man.
While I was working, I realized that I felt strongly that higher education was important. I applied to three schools: the University of Melbourne, the City University London and Old Dominion University. I know it sounds like a diverse choice of schools, but I knew people who were either at those schools, or had been. In fact, the son of a friend of my father's was at ODU. I was accepted at all three schools, and chose to come to the United States in 2002.
I took a cab from the Norfolk airport to the dorm at ODU, and the cab driver asked my name. When I told him my given name, which is Chrysostomos, he said he'd just call me Tommy. And that stuck.
I was amazed as we were driving at the size of the cars and the trucks and the large four-lane highways. I'd never seen anything like it! It was very exciting.
Back in third grade, we had a choice of what language we would study, and I chose English. I've been able to speak it well [actually, my given name means ''well spoken''] but I had a lot of trouble writing it correctly. I needed to take English as a Second Language classes to get up to college-level writing.
One thing I didn't struggle with at all was American food. Growing up, we were a very conservative family and there was only one way to cook things, and our food was simple. I loved all the choices I found here – especially ranch dressing!
I stayed at ODU for one year, and quickly realized that I could take the same courses at Tidewater Community College at a much lower cost, so I transferred there for my sophomore year and returned to ODU after that.
During school, I met the woman who would become my wife, Jennifer. She was working toward her Doctor of Physical Therapy degree. I graduated on May 5, 2007, with a bachelor of science degree in electrical engineering and we were married two weeks later.
After graduation, I worked as a software engineer for two years at an area company that made book-binding machines. There were rumors that the company was not doing well and would be closing, so I decided to leave before that happened. I went to work as the lead electrical engineer at Bauer Compressors in Norfolk. The commute from our home in Hampton was grueling and we were starting our family, so I was interested in finding something closer to home. A friend mentioned an opening at Jefferson Lab, and I decided to apply.
The interview was like nothing I'd ever experienced before! There were eight engineers in a room with no windows, all asking me very technical questions. I was very rattled.
My next and current project is with the radiation-protection ion chambers in the experimental halls. They are sensors that are strategically put in place around the beam line and the dumps to protect the electronics from prompt ionizing radiation.
Safety here is a state of mind. It's a lot of responsibility to know that you're the person who has to think about what could go wrong – and to make sure it doesn't.
My wife works at Riverside Hospital's rehabilitation center, and we have a young son, Andreas, who's named for my father, so our life is very busy. I'm also working on my master's in electrical engineering, specializing in controls, at ODU, and hope to finish by 2015.
The past few several months have been exceptionally busy. Early this year I was in Austin, Texas, for courses at the U. S. Particle Accelerator School, and we spent time with my family in Cyprus over Christmas. And late last year I became an American citizen. There were about 100 of us at the Federal Courthouse in Norfolk taking the oath, and we had a big cookout at our house to celebrate. It was a very big moment for our family.
Everyone at the lab has been so helpful, and so welcoming. I really like being here; this is the best job I've ever had.
As told to Judi Tull
The Engineering Division's Safety Systems Group specializes in high-reliability engineered systems used to protect people and equipment from hazards unique to accelerator and test facility operations. Jefferson Lab's safety systems include personnel safety systems (PSS), machine protection systems (MPS), and the beam envelope limit system (BELS).
In their work, Safety System Group members adapt and apply engineering standards, practices, and training from other high-assurance disciplines such as aerospace, defense, and chemical process controls.
Tommy Michaelides' work for SLAC included programming safety logic controllers as part of an upgrade to the Linac Coherent Light Source, or LCLS, a powerful accelerator driven X-ray research facility. He also worked on the central control safety systems for FACET, the Facility for Advanced Accelerator Experiment Tests, a test bed for advanced accelerator concepts like plasma wakefield acceleration.
JLab uses the same safety controllers for the Hall D safety systems, as part of the 12 GeV Upgrade project. Ion chambers are used in the CEBAF experimental halls to protect unique and sensitive equipment and the high power beam dumps. Ionization chambers create a measureable current proportional to the flux of ionizing radiation passing through a gas filled tube.
The JLab MPS ion chambers are used in areas where they must discern between a nominal level of background prompt ionizing radiation such as beam centered on a thin window or an experiment's target, and the higher prompt radiation produced when the beam strays off into a thicker piece of material like the target frame or beam pipe. When this abnormal condition is detected, the ion chambers shut off the beam before there is permanent damage to the frame or the beam pipe.More about the Safety Systems Group is online at: http://www.jlab.org/accel/ssg/
Protons and neutrons are the fraternal twins of the sub-atomic world and the building blocks of all atomic nuclei. While similar in many respects, it's their differences that give them their unique properties. Now, scientists are exploiting these differences to gain deeper insight into these fundamental particles that build our visible universe.
According to Wally Melnitchouk, a theorist in Jefferson Lab's Center for Theoretical and Computational Physics, by probing both the proton and the neutron, scientists can better learn how the different proportion of quarks yields different properties for these particles. Melnitchouk is a spokesperson for a collaboration of researchers who are conducting an experiment at Jefferson Lab to probe these particles.
"The proton is just one combination of ups and downs. So with the proton data alone, we cannot determine both up and down, we need the neutron," he says.
But probing the neutron is tough, even for Jefferson Lab's Continuous Electron Beam Accelerator Facility, which was built to probe the subatomic realm. CEBAF fires a beam of electrons into the nuclei of a target material. It can thump, transform or knock out particles that reside in the nucleus, so that scientists may study them.
However, there are no "free" neutrons to study. Once formed, a neutron that is not bound inside the nucleus of an atom will dissolve into simpler particles in minutes. "To study free neutrons, you'd have to replace your target every 10 minutes," Melnitchouk explains.
Sebastian Kuhn, also a spokesperson for the experiment, as well as chair of the Jefferson Lab Users Group and a professor at Old Dominion University, says the experiment is, therefore, taking aim at the next-best thing: an isotope of hydrogen, called deuterium.
"What people are left with are nuclei that contain neutrons. And the simplest nucleus that we can possibly use is the deuteron; it's just one proton and one neutron. And that's what people have tried to study as an approximation to a free neutron. Subtract the proton and hope to get the free neutron," Kuhn explains. "What we set out to do with this experiment is to eliminate as much as possible any effects on the neutron, due to the fact that it's bound in a nucleus."
To minimize these effects, the scientists probed only those neutrons that were very loosely bound. Such neutrons had very little interaction with the proton in the nucleus immediately before or after the reaction. Knocking out the neutron disintegrates the nucleus, releasing the proton.
"There's a proton and a neutron: you hit the neutron, and the proton becomes a spectator, it just watches what happens to the neutron. So you look for that proton to come out," Kuhn says. "We only choose events where the proton was moving backwards relative to the electron beam, and at low momentum. Those are the two signatures we use to distinguish spectator protons from anything that was involved in the reaction: backward and slow."
The scientists developed a new piece of equipment, the Radial Time Projection Chamber, to capture and measure the slowly moving protons.
The experiment, dubbed BoNuS (for Barely Off-Shell Neutron Structure), was carried out in Jefferson Lab's Experimental Hall B in the fall of 2005. After careful and detailed analysis, the results were published in the April 8 issue of the journal Physical Review Letters.
Among other results, they studied the likelihood that scattering electrons can alter the neutron to form so-called resonances.
"A resonance is an excited state, which basically means that the internal configuration of the quarks changes in a well-defined manner. For instance, one quark changes its spin, or two quarks start moving around each other, or some other changes of the internal motion occurs that lead to a new, more energetic state of the neutron," Kuhn says.
While some of the proton resonances are well-documented, there has been little exploration of the neutron resonances, since, until now, the neutron has been difficult to probe. This is the first experiment to reveal a sequence of neutron resonances. Encouragingly, the sequence appears to, in some ways, mirror the sequence of proton resonances.
"This will allow us to study the differences between the spectrum of resonance excitations of the neutron and the proton," Melnitchouk says. "We now have a way of directly studying the structure of the free neutron; this is just the first glimpse. But this experiment demonstrates that this method works and opens up a whole new range of experiments to study the structure of the neutron."
Beyond new information of resonances of the neutron, the BoNuS experiment also offers a direct view of the motion of the quarks inside the neutron.
The scientists say now that the experimental method has been confirmed, they plan to use it in future experiments with the energy-upgraded electron beam at Jefferson Lab to continue probing the neutron, in hopes of revealing more of its structure and of the behavior of the quarks inside.
"For the first time, we can directly compare the structure of the neutron to that of the proton, and we can then start explaining the differences in terms of fundamental properties of bound quark states," Kuhn says.
By Kandice Carter
ComWould you benefit from a meeting with a colleague, but have a tight travel budget or just don't have the time to go to a distant location? Or a group of far-flung collaborators needs to hold a real-time discussion regarding the data analysis for their experiment? Or one of your conference or workshop guest speakers just called to let you know that bad weather has grounded their flight?
The answer to these and other communications situations may be using the expanding webinar capabilities available through Jefferson Lab's Information Technology Division.
"There have been improvements and new services added to the webinar and videoconferencing capabilities available to the Jefferson Lab community," says Jessica Perry, Help Desk manager.
The primary webinar tool supported at JLab is ReadyTalk. It has been demonstrated as highly efficient and user friendly. It allows you connectivity anytime, from almost anywhere, supports visuals, and requires minimal resources, according to Perry. Once you have ReadyTalk, you can set up a meeting weeks in advance or on a moment's notice.
"We support and encourage the use of ReadyTalk," she adds. "It is considered user friendly and nearly all the national labs make this resource available."
ReadyTalk can be used on demand for any size of meeting: from two people conversing from their offices located across the Peninsula or halfway around the world from each other, to 96 participants, in as many locations, taking part in a conference or workshop. The system can accommodate up to 150 on request, and can handle up to 3,000 participants with personalized operator services.
ReadyTalk works internationally and provides information on the service's website for international conferencing access numbers. Visit: http://www.readytalk.com/legacy/an.php?tfnum=8667401260 or http://www.readytalk.com/account-administration/international-numbers
To use ReadyTalk, the person initiating the meeting needs a ReadyTalk account. Everyone participating in the meeting needs only a phone line or phone connectivity over your computer, and a computer with Internet connectivity. The system provides real-time dialogue and a visual interface for sharing things like PDF documents and PowerPoint briefings. You don't need a conference room, a camera or any set up support. And if your phone is through your computer, ReadyTalk can even be used in locations such as airports with wireless connectivity.
When you need full-fledged videoconferencing, the CNI group can provide resources for using EVO (Enabling Virtual Organizations) and audio-video conferencing with a Polycom.
EVO is a videoconferencing system designed by CalTech that is available at many of the national labs and U.S. academic institutions. EVO can be used from a number of JLab conference rooms, according to Perry.
Both ReadyTalk and EVO require setting up an account – in advance of your meeting. The ReadyTalk system only needs the chairperson of the webinar to have an account, the rest of the participants do not need an account. Plan on three to five business days to set up a new ReadyTalk account. But once an account is established, scheduling and conducting meetings is quick and easy. A new EVO account can be set up in a day.
"These are great resources for real-time visuals and face-to-face discussions," Perry notes. "Using these utilities can save you time and money while providing a valuable communication interface."
Check with your collaborators, before deciding which system to use, Perry suggests. "And check in with the Help Desk regarding current capabilities. Some of this technology is advancing at a rapid rate."
All JLab staff and registered members of the lab's Users Group can use these lab resources. Tutorials are available on the Computer Center website. Hands-on training is available on request.
Perry also encourages those who use these resources to provide the Help Desk with feedback. "Let us know which utility you used, how you are using it, and how well it performed or met your needs."
These are communications services supported by Jefferson Lab's IT Division and are found across much of the larger Department of Energy system. ReadyTalk, which is one of the ESnet Collaboration Services, is funded by the Department of Energy.More information about these systems is available on the Computer Center Intranet site; Look under the Infrastructure tab at: https://cc.jlab.org/
The On Target newsletter is published monthly by the Thomas Jefferson National Accelerator Facility (Jefferson Lab), a nuclear physics research laboratory in Newport News, Virginia, operated by Jefferson Science Associates, LLC, for the U.S. Department of Energy's Office of Science. Possible news items and ideas for future stories may be emailed to email@example.com, or sent to the Jefferson Lab Public Affairs Office, Suite 15, 12000 Jefferson Avenue, Newport News, VA 23606