Herman Batelaan, above, along with his physics teammates Daniel Freimund and Kayvan Aflatooni, observed the Kapitza-Dirac effect in their lab in UNL's Behlen Laboratory for Physics in April. An article about their discovery appears in a recent issue of Nature magazine.

NU Team Observes, Confirms Suspected Physics Phenomenon

By Tom Simons, University Communications

The shimmering green light of the lasers in Herman Batelaan's UNL laboratory is more than just pretty. It was the critical element in Batelaan's team becoming the first to observe the Kapitza-Dirac effect, an accomplishment that could make possible measuring devices that are thousands of times more accurate than those in use today.

The Kapitza-Dirac effect is the diffraction of a beam of particles, electrons in particular, by a standing wave of light. It was predicted in 1933 by a pair of future Nobel Prize winners, Russian Peter Kapitza (1894-1984) and Englishman P.A.M. Dirac (1902-84), but the technology needed to demonstrate it didn't exist at the time, and wouldn't until well after the laser was invented in 1960.

Early lasers weren't capable of producing the Kapitza-Dirac effect and it wasn't until April 11, 2001, when it was observed for the first time in Batelaan's lab in NU's Behlen Laboratory for Physics.

The confirmation was reported by Batelaan and his team of Daniel Freimund and Kayvan Aflatooni in the Sept. 13 issue of Nature, the international weekly journal of science. Freimund, the lead author of the Nature article, a doctoral candidate under Batelaan, earned his bachelor's degree in mechanical engineering and his master's in physics at Nebraska. Aflatooni, who was a post-doctoral researcher in Batelaan's lab at the time of the discovery, earned his bachelor's, master's and doctoral degrees in physics at Nebraska and now is an assistant professor of physics at Fort Hays (Kan.) State University.

A basic physics experiment that illustrates the wave nature of light involves placing a screen with two slits in it at a distance from a point source of light and placing a second screen beyond the first. Instead of two bars of light appearing on the second screen directly in line with the light and the slits, multiple light bars appear across the second screen. That's because the slits diffract the light and the bars mark the convergence of light waves. It's Quantum Mechanics 101.

Batelaan and his team in essence repeated that experiment in April, except they used an electron beam instead of a light beam and substituted a laser beam for the slitted screen. They saw that the electrons were diffracted by the laser, just as Kapitza and Dirac had predicted 68 years earlier.

Scientists have long used diffraction of optical, acoustic and radio waves in interferometers, devices that among other things measure very small distances and thicknesses. They're also used as rotation sensors in the avionics systems of airplanes. And now that Batelaan and his team have shown that particle waves can also be diffracted, Batelaan said it's possible that particle waves can be used to make a much more accurate interferometer.

"The average wavelength in a laser beam is one micron (one-millionth of a meter), which is 1 percent of the thickness of a human hair," Batelaan said. "The wavelength of this electron wave, because the electrons also have a wave, is 10,000 times smaller. That's the size of one atom.

"If you use the Kapitza-Dirac effect multiple times, you can make an interferometer. But we haven't done that yet. We're trying to figure out what the implications are for use in rotation sensors and electromagnetic field sensors."

Batelaan and his team observed the Kapitza-Dirac effect with funding from the Research Corp. A $350,000 grant received in July from the National Science Foundation will help start the search for an electron wave interferometer. Batelaan said he's excited about the possibilities of the ongoing research, but that doesn't keep him from savoring his team's discovery.

"The effect was predicted in 1933 and we were the first ones to observe it - and that's kind of nice," he said, sitting in his office beneath portraits of Kapitza and Dirac. "There were four attempts in the 1960s, but they all failed. If someone had tried it in the '90s, they would have pulled it off, so in a sense we're a bit lucky. But, hey, you need luck."

High Schools, WSC Join Cosmic Ray Project

By Tom Simons, University Communications

UNL's Cosmic Ray Observatory Project has added five Nebraska high schools and Wayne State College to its list of participants in the 2001-02 academic year.

The new high schools are Anselmo-Merna, Lincoln Lutheran, Lincoln High, Omaha Westside and Osceola. They join last year's initial group, Elkhorn Mt. Michael, Lincoln Northeast, the Lincoln Science Focus Program, Norfolk and Omaha Marian, to give CROP 11 sites.

Created last year through a $1.34 million grant from the National Science Foundation, the CROP project seeks to install cosmic ray detectors at as many schools as possible across Nebraska and link them via the Internet in what would be the geographically largest cosmic ray detection network in the world. Each school's equipment includes a detector to register the impact and energy of cosmic rays, a Global Positioning System device to record the exact time and place of the strikes, and a personal computer to keep track of the data and link it to other CROP sites.

Schools' science classes can set up their own experiments, but they will also be part of a much larger experiment coordinated by NU physicists Greg Snow and Dan Claes.

"In the typical high school science experiment, everything is canned, presented recipe-style and designed to be completed in a 45-minute period," said Claes, a former high school physics teacher. "The answer is sort of predictable. But here, they will actually be part of a long-term, ongoing experiment that, like any real research project, carries no guarantees. They'll learn a little bit about what scientists do, but more importantly, they'll come away with the impression that what scientists do is fun and interesting, and worth pursuing."

The students and their teachers will be part of an effort to learn more about two key features of cosmic rays that scientists don't understand - where they come from and how they achieve their high energies.

"Some primaries (single protons) carry the same energy as a driven hockey puck," Claes said. "There is no known phenomenon, not even the explosion of a star, that we believe can drive a proton to that high an energy. Yet they exist, and we don't know where they come from."

Snow said the planned wide geographic distribution of CROP's detectors could help answer those questions.

"One of the nice features about our experiment is the detectors are spread out over a much larger geographic region than any of the other major enterprises that are being mounted to study cosmic rays," he said. "In a certain way, we have an unprecedented sensitivity to judging whether or not an area the size of Nebraska lights up all at once. Because of the GPS equipment we'll be able to tell if all the schools detect a big bunch of particles coincidentally."

More than 800 gathered at Kimball Recital Hall on Sept. 14 to pay tribute and remember those killed in the Sept. 11 tragedy in New York City and Washington, D.C. Those at the UNL memorial service heard comments from Chancellor Harvey Perlman and ASUN President Nathan Fuerst. Then, all stood to sing America the Beautiful.

CAPS, EAP Offer Services After Attacks

By Nancy Myers, director, EAP

To help faculty members and students cope with the events of Sept. 11, Counseling and Psychological Services and the Employee Assistance Program offer suggestions, information, and counseling to any members of the university community. For more information visit CAPS Web page at: <www.unl.edu/health/CAPS.html> or the EAP's Web page at: <http://busfin.unl.edu/hr/eap.html>

The events of Sept. 11 will, for many people, evoke strong and intense responses. These reactions are normal and natural considering the horror of the incident. Some reactions:

• Emotional shock; feeling distracted and/or frightened.
• An urgent need to hear the latest news or track the sites of terrorism, and sadness at the loss of victims, a desire to learn about the perpetrators and the hope for a response that will bring safety.
• Inability to focus on daily tasks and/or loss of interest in usual activities.
• Insomnia, frequent waking or nightmares.
• Loss of feeling safe.
• Fear of war and uncertainty over our government's response to these acts.
• Agitation and/or irritability.
• Anger or denial.
• Overworking as a distraction.
• Feelings of helplessness and/or survivor guilt.
• The reawakening of past traumas.

For most people, these symptoms will lessen over time. To help yourself and others, these suggestions may be helpful:

• Take care of yourself, your family and loved ones by contacting each other for reassurance and support.
• Listen carefully.
• Talk frequently to others about your responses and the impact of these events on your family and our country.
• In response to highly stressed people in class or at work, be supportive. Be aware of their reduced ability to concentrate or their diminished productivity.
• Encourage tolerance and calm. Be aware of the backlash against people who share an ethnic/cultural/religious heritage with those accused.
• Avoid blame, speculation and inflammatory language.
• In groups, allow everyone a chance to talk but don't force anyone to participate.
• Encourage positive actions to take in response to this tragedy, such as donating blood or money and reaching out to others/volunteerism.
• If talking doesn't help, encourage non-verbal expression such as writing, drawing, playing or listening to music, dance and/or exercise

This is a time of uncertainty and as events unfold in response to the terrorist attacks, individuals may experience additional stress. It may be useful to think about what has been helpful in the past when dealing with difficult times. For example, some people have found that turning to spiritual support is very soothing; others may need to talk or focus on self-care.

Traumatic events can overwhelm a person's sense of control, connection and meaning. There can be feelings of extreme vulnerability from the terrorist event and at the same time horror at the capacity for evil in human nature. The victims of this event need help from others to share the burden of pain. The outpouring of volunteerism, donations of money and blood and visual symbols of patriotism are positive ways to contribute as a whole. Those who have lost loved ones will need the sustenance of others for many months. According to Herman (1992), recovery from trauma unfolds in three stages. The first stage is the establishment of safety. The second is remembrance and mourning and the third is an ability to reconnect with others. Because those who have been traumatized are often depleted of energy similar to that of intense grief and loss, the presence of others over a sustained period of time is essential for the healing process to begin.

Trauma can be insidious. It is sometimes difficult for those experiencing trauma to recognize their symptoms. Others may be in a state of denial. Talking about what you are going through in the wake of these strong feelings is the most important thing that you can do to take care of yourself and others.

For help Faculty, staff and their family members who want help at this difficult time should contact UNL's Employee Assistance Program at 472-3107 or (800) 755-2655. Students in need of counseling may contact Counseling and Psychological Services (CAPS) at 472-7450.

Stadium Security Beefed Up for Rice Game

The University of Nebraska football game with Rice will kick off at 7:30 p.m. Sept. 20. Originally scheduled for 6 p.m. Sept., 15, the game was moved to a 6:30 p.m. kickoff on Thursday, because of the tragedies suffered in New York, Washington, D.C., and Pennsylvania. Every Division I-A football game scheduled for last week was postponed. The game time has been moved back one hour to reduce the disruption of regularly scheduled classes, and for security reasons.

The later kickoff time will allow more time between classes held during the day and the start of the game, providing more time for campus and downtown traffic to clear the area for fans. With the change in game time, many classes can be completed without relocation. Most of the night classes have been relocated to East Campus, except for labs and those requiring special equipment or accommodations. Students and staff are asked to leave parking lots by 5 p.m., and incoming football fans are asked to exercise patience as Nebraska plays its first-ever Thursday night game in Memorial Stadium when school is in session.

The Huskers have played on Thursday before, most recently on Aug. 31, 1995, at Oklahoma State to open the season, and on Sept. 8, 1994, at Texas Tech. Both games were televised on ESPN. Nebraska also played on Thursday at home when it played host to Oklahoma on Thanksgiving day in 1965, 1967 and 1972. However, those games were played on a holiday when school was not in session. With the change of date, Nebraska's game will no longer be televised, although Fox Sports Net still owns the rights.

UNL Chancellor Harvey Perlman said he appreciated the united campus effort when the game changed from Saturday to Thursday.

"I applaud our students, faculty and staff for helping us make this game a reality," he said. "We had no other options but to play on Thursday. We hope that moving the game time back an hour will facilitate game traffic and will keep the interruption of classes to a minimum."

Athletic department officials have held several meetings to discuss security measures. Moving the game time back an hour will also help with security. The normal process of clearing each campus building on game days before the game takes a minimum of two hours. The additional hour before game time will help provide adequate time to carry out security measures.

Nebraska has always had stringent security measures in place for all sporting events, including evacuation plans in case of lightning storms or other emergencies. Director of Events Butch Hug has been working closely with Campus and Lincoln Police and with his event staff to make sure that current security measures are reviewed. Additional considerations have been made in this time of national unrest.

As a result, Husker fans will find that additional security measures will be taken for fans entering Memorial Stadium this week and for all future contests. Daily access to the stadium will be restricted and a thorough search will be conducted of all parts of the stadium on game day. Vehicles will not be permitted under the stadium, and all deliveries will be inspected. As has been the policy in the past, fans will not be allowed to bring glass, cans, large coolers, backpacks, video cameras, parcels or umbrellas into the stadium. All purses and bags will be subject to inspection before entering the stadium. Passouts will continue to be allowed, but those who exit the stadium will not be allowed to carry any items back into the stadium.

"Security and safety have always been our highest priority and our goal is to continue to make the game-day experience fan-friendly, but we must all begin to operate under a higher level of security awareness," said Director of Athletics Bill Byrne.

City meters on 14th and W streets and on Stadium Drive will be posted on Wednesday and will not be available for parking on Thursday.

The Husker athletic department policy, as stated on the tickets, says "date and time subject to change" and "no refunds, no exchange." However, in light of the trying circumstances, fans who are unable to make it back for the game will be allowed to donate their tickets to Nebraska students who do not have tickets to the game. Fans wishing to exercise this option, which is in effect for this game only, can express mail or deliver their ticket to the Office of the Vice Chancellor for Student Affairs, 106 Canfield Administration Building, 14th and R streets, Lincoln, NE 68588-0423. Tickets must be received at this office by noon Thursday. Donors should include their name and address in order to receive a later confirmation of the donation. The donated tickets will be distributed free to Nebraska students with a valid student I.D. card who are not current NU football ticket holders. The distribution of the donated tickets is scheduled for Thursday, from 3-4 p.m. at the Nebraska Union.

The University of Nebraska and the American Red Cross will be collecting funds for the victims of last week's tragedies at the football game. All funds collected will go to the American Red Cross Disaster Fund. Husker student-athletes and Red Cross volunteers will collect funds both before and after the game.

As a thank you to fans, the university will hand out 40,000 bumper stickers that say "United we Stand." The stickers were provided by the athletic department, Pinnacle Sports Productions, Alltel and U.S. Bank.

Rearranged Workdays Encouraged Because of the Sept. 20 football game, supervisors are asked that if it can be done without disrupting important university activities, employees be allowed to rearrange the work day to allow them to leave campus by 4 or 4:30 p.m. The request applies to both City and East campuses. This allows a more orderly traffic flow that day in anticipation of game day crowds. Campus buildings will close at 6 p.m. Bruce Currin, assistant vice chancellor for human resources, suggests that employees be allowed to start earlier in the day or take a shorter lunch that day. Regardless of when they finish their day, employees are asked to leave university parking facilities as soon as possible on Sept. 20.