April 13, 2020. Al was born in Milwaukee, Wisconsin, he was the youngest son of Fred and Martha Clark. Al received his bachelor's and master's degrees from the University of Wisconsin and his PhD in nuclear physics from the University of Michigan. He moved to Boulder in 1964 to pursue post-doctoral studies at the Bureau of Standards, now NIST. A cryogenic and materials physicist, Alan was with NIST, in both the Boulder and Washington DC labs, from 1964 -2004. He held several positions there, published over 150 papers and held one patent, and worked in a collaborative capacity in England for several years. He was inducted into the NIST Portrait Gallery. Following his retirement from the federal government, he served as chairman of the Department of Physics at the University of Colorado – Denver.

Al received his bachelor's and master's degrees from the University of Wisconsin and his PhD in nuclear physics from the University of Michigan. He moved to Boulder, Colorado in 1964 to pursue post-doctoral studies at the Bureau of Standards, now NIST. A cryogenic and materials physicist, Alan was with NIST, in both the Boulder and Washington DC labs, from 1964 -2004. He held several positions there, published over 150 papers and held one patent, and worked in a collaborative capacity in England for several years. He was inducted into the NIST Portrait Gallery. Following his retirement from the federal government, he served as chairman of the Department of Physics at the University of Colorado - Denver.

Al was the first chair of the IEEE Superconductivity Committee, the predecessor of the IEEE Council on Superconductivity. He also served as the Editor-in-Chief of the IEEE Transactions on Applied Superconductivity from 1994 to 1997. He was a founder and past Chairman, International Cryogenic Materials Conferences (1975-1987). Al was a member of the board of directors of the Applied Superconductivity Conference and served as Chairman of the 1990 Applied Superconductivity Conference held in Snowmass, CO. He was a prolific author with over 150 peer reviewed papers.