He made contributions to the field of cryogenics as inventor during the 1940s through the 1960s, and subsequently as an executive and member of the Board of Directors of both ADL and the Helix Technology Corporation, of Waltham, Massachusetts.
During his undergraduate years, in the depth of the Great Depression, when his parents were unable to help pay his college tuition, he developed and patented a device later used in bubbling Christmas tree candle lights.
We had to dream up the way to do it.” [5] McMahon was also one of a number of Arthur D. Little scientists and engineers who were employed in supporting roles when the U.S. government was completing development of the first hydrogen bomb at the Los Alamos Laboratory of the Atomic Energy Commission in 1952.
Another application was “in support of the early U.S. space program,” when the Gifford-McMahon refrigerator “was used initially to cool microwave amplifiers in ground stations for satellite communications.”.
[8] In the 1960s, as McMahon rose from the research laboratory through the ranks at ADL into managerial positions, the company at the same time increased the proportion of its consulting work that was devoted to a wide variety of management problems brought to it by clients that included corporations, municipalities and governments outside the U.S.;[9][10][11] By 1966, in addition to employing 1,300 staff in the Cambridge headquarters, ADL had another 100 employees in branch offices in Zurich, London and Brussels.
According to one interview-based account, “It was largely on McMahon’s initiative that students and young scientists were invited for the first time to organize a formal critique of science.
‘The activists prodded the scientists into a greater sense of urgency over the issues of the day—the quality of life, the arms race, population control, hunger, our national scientific priorities.
during these years was as a panelist at a seminar held by the Department of Aeronautics and Astronautics, on the topic “The Engineering Profession and Social Change,” February 9, 1971.
When McMahon stepped down as ADL President in early 1972, he devoted much of his energy to helping guide the development of new cryogenic products by CTI and its parent company, Helix Technology Corporation.
In the mid-1970s, a cryogenic vacuum pump based on the Gifford-McMahon refrigeration cycle, making possible the processing of silicon wafers for the new microelectronics industry in clean, high-vacuum chambers, was developed at Helix.