Claude Woodrow Sill, 95, of Idaho Falls, died August 1, 2014, at Fairwinds - Sandcreek Assisted Living Facility. He was under the care of Aspen Home Health and Hospice. He was born October 29, 1918, in Layton, Utah, to Marietta Welling Sill and Joseph Albert Sill. He grew up in Layton and graduated from Davis High School in 1935. He was the last surviving sibling of 10 children. He attended the University of Utah and received an AB and MA in Chemistry. He served in the United States Navy from April 1944 to June 1946. He was stationed in the Pacific Ocean during WWII. He married Lorraine Betty McAllister in Idaho Falls on March 1, 1955. Lorraine died on March 8, 2008. He was a Research Chemist with the US Bureau of Mines in Salt Lake City from 1942-1951. He then became Chief of the Analytical Chemistry Branch, Health Services Lab, for the US Atomic Energy Commission, and its successors, ERDA and DOE in Idaho Falls from 1951-1977. From 1970-1980, he was the Sr. Scientist for the Radiological and Environmental Sciences Lab at DOE. He was the Scientific Specialist for the Materials Science Branch of EG&G from 1980-1983. He was the Principal Scientist of the Chemical Sciences Group of EG&G from 1983-1995, when he retired. He was a member of the Church of Jesus Christ of Latter-day Saints. Claude was a world renowned Radiochemist, second to none. In the early 1950's, he set up the Radiological and Environmental Sciences Laboratory, the first analytical laboratory for the Department of Energy that was devoted to Radiochemistry in support of the Manhattan project. He and his top-notch staff developed analytical procedures for the determination of the actinides that are still state-of-the-art today. During his professional career, Claude published over 150 papers, contributed to numerous books and routinely gave presentations on the newest developments in Radiochemistry at scientific meetings. For over forty years, Claude and his chemists were the principle contributors to the yearly international Bioassay Conference. Claude received a personal letter of commendation from the head of the Atomic Energy Commission for his sustained meritorious service to the field of analytical radiochemistry. These contributions are unheard of by today's standards. Our father was a devoted and wonderful man with unconditional love for his family. He has missed his dear wife terribly since her passing. They are now reunited and will forever be in our hearts. Survivors include: Daughter, Claudia L. (Jeff) Clark of Idaho Falls Son, David S. (Kimberly) Sill of Shelley Step-son, Doug Schoeneman of Battleground, Washington 6 grandchildren and 8 great-grandchildren He is preceded in death by his wife, Lorraine, and infant son, Steven Claude Sill; brothers: Joseph Ralph Sill, Sterling Welling Sill, Russell Welling Sill; sisters: Mabel Sill, Marietta Sill, Genevieve and Marguerite Sill (twins), Laura Louise Sill, and Alta Mae Sill. Graveside services will be held at 11:00 a.m., Tuesday, August 5, 2014, at Fielding Memorial Park Cemetery, Idaho Falls, under the direction of Coltrin Mortuary. Condolences may be sent to the family online at www.coltrinmortuary.com.