Father of Meson Accelerator Louis Rosen dies

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By Carol A. Clark

Renowned Los Alamos National Laboratory scientist Louis Rosen died in his sleep at 6:30 p.m. Thursday from complications of a subdural hematoma.


Rosen, 91, apparently fell in the early hours of Saturday Aug. 15 at his Los Alamos home. He was airlifted to UNM Medical Center in Albuquerque where he remained until late Thursday afternoon.

“Papa Louie had just been transferred to Sombrillo Rehabilitation Center in Los Alamos before dying peacefully and elegantly and surrounded by his family,” granddaughter Ambyr Hardy said. “It’s profound for us that we got him home.”

Rosen’s two grandchildren, Hardy and her brother Terry Rosen and three of Rosen’s four great-grandchildren were with him when he died.

LANSCE Executive Administrator Ginger Grant also was with the family. “I loved him so much,” she said. “He was a giant of a man – so humble and so generous with his knowledge. It just breaks my heart and I’m missing him so much.”

Rosen would have felt at home at Sombrillo, his grandchildren said, because he spent so much time there caring for his beloved wife Mary Rosen before her death in October 2004.

“He was always so humble about himself that I feel he really never understood the potency of his interactions with people,” Terry said.

Hardy agreed saying, “Papa Louie thought of himself as this regular person and yet he was so extraordinary. As  children we’d go with him to Santa Fe and it seemed as if everyone knew him.”

Rosen was as busy and engaged as ever just days before his death. He went to work at the laboratory as usual on Thursday Aug. 13, his family said.

Many people are coming forward with remembrances of their relationships with the internationally recognized scientist.

“LANL offers our deepest condolences to the Rosen Family,” said Director Michael Anastacio of Los Alamos National Laboratory. “This is a great loss of a great man. He was the father of our LANSCE Facility and an inspiration to us all. Louie embodied the passion for innovation and the commitment to succeeding generations of scientists. Just last month he gave a lecture to students at our Neutron Scattering School, which was very well received. He was as passionate about our next generation of scientists as he was about those he inspired when he began working here in 1944. We will all miss him.”

Rosen was born in New York City on June 10, 1918. He received his bachelor’s and master’s degrees from the University of Alabama and his PhD from Pennsylvania State University. He later taught at both universities.

In 1944, Rosen joined the laboratory as a member of the Manhattan Engineering District’s Project Y.

His wartime work in neutron cross-section measurements and nuclear test diagnostics proved immensely valuable.

After the war, many scientists left the Laboratory to pursue careers in industry or academia, but Rosen remained.

To help ensure that Los Alamos continued to be a premier science institution, Rosen led the way in developing the world’s most powerful linear accelerator.

His efforts culminated in the construction of the Los Alamos Meson Physics Facility, which is known today as the Los Alamos Neutron Science Center (LANSCE). Rosen served as director from its inception to 1986.

Current Director Alan Hurd of the Lujan Neutron Scattering Center at LANSCE was attending a conference out of town when he received word of Rosen’s death. Hurd and Rosen maintained a close collaboration, sharing monthly lunches and meeting often to discuss science.

“While we at LANSCE are deeply saddened by his passing, we rejoice in the remarkable impact he has had on many generations of scientists – numbering thousands – who use and have used particle beams at Los Alamos for research. Louie was one of our last personal touch points with the Manhattan Project,” Hurd said. “He spent much of this year recording and assessing the legacy of that era on Los Alamos and LANSCE today.  Since new stories about the Manhattan Project continually arose from his crystalline memory, I am sure he ran out of time telling that history.  However, a three-part interview of Louie on the “Behind the White Coat’ series for PAC 8 television as well as his own manuscripts capture his most enduring memories, which he discussed in a series of lectures to the lab community this summer.”

In the 1960s, Louie battled through political and scientific barriers to create the first megawatt proton accelerator, still the world’s most powerful until the Spallation Neutron Source surpasses it in a few months, Hurd said, adding that Rosen has been a valued counsel to those navigating today’s political battlefield to refurbish LANSCE and to enhance the Lujan Center.

“Louie understood LANSCE’s importance to the lab’s future and he would occasionally wield his powerful political connections in the cause,” Hurd said. “We will miss Louie’s inspiring spirit, which he communicated by confidently striding to work every day into the last week of his life. He loved to interact with students. In my favorite image, he is surrounded by a flock of graduate students lucky enough to hear about the time he and his colleagues set the forest on fire during the War. Though he regretted the loss of ‘Oppie’s Lab,’ he always gave constructive advice on how to move the scientific agenda forward no matter the environment. Last week he told me that his challenge was to find ways to continue to contribute to society. Did he ever.”

Esteemed LANL scientist and founder of the Santa Fe Institute, George Cowan, spoke of his longtime friend.

“Louie was at Los Alamos when I got here in 1945 and I’ve had many, many associations with him over the years,” Cowan said. “We’ve grown old together and I think of him as one of my very close friends. I know I’m going to miss him – I think everyone will.”

Hardy and her family visited Rosen in July and Terry visited him recently as well.

“Our grandfather had an opportunity to hold my 4-month-old son. He was doing so well and we all had such a wonderful time together,” Hardy said. “We all have really great final memories of him – so alive and vital.”

During his career, Rosen received many honors. In 1963, he won the E. O. Lawrence Award for the development of new experimental techniques and their application to a better understanding of the atomic nucleus as well as to the diagnosis of weapon behavior.

Rosen also received the prestigious 2002 Los Alamos National Laboratory Medal – the highest award the Laboratory bestows upon an individual. Funeral arrangements and public services will be announced soon.

Contact Carol A. Clark at lanews@lamonitor.com or (505) 662-4185 ext. 25. Read her newsblog at www.newsextras.wordpress.com.