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Phyllis St. Cyr Freier Papers

Identifier: 1026

Scope and content note

The collection consists of correspondence, reprints of published research articles, class materials, and a collection of research notebooks containing data for cosmic ray experiments.

The correspondence (1948-1990) includes fellow physicists as well as members of the Committee on the Status of Women in Physics. Of particular note is an extensive series of letters from Frank Oppenheimer (1949-1955) who resigned from the University in June, 1949, after having been subpoenaed by the House Un-American Activities Committee regarding his Communist Party membership from 1937-1940. After they moved to a Colorado ranch Frank and his family continued their friendship with the Freiers, who visited there from time to time. There is one folder of correspondence related to the University of Minnesota Senate Judicial Committee.

The research publications are filed in the chronology of the date of the submission of the article, rather than the publication date.

Box 2 includes a series of 24 research notebooks, recording experiments made between 1948 and 1960. Freier prepared an "Index of Notebooks" which serves as a guide to the chronology of the series although not all of the notebooks are included in her numbering system. Note that entries marked in red have been deleted from the collection. Notebook No. 5 recorded data from the historic balloon flight of April 21, 1948, which led to the definitive cosmic ray discovery.

In addition Box 2 contains: l. An album of technical photographs related to International Geophysical Year research; 2. A folder entitled "Julio's Pictures" depicting the building of a research facility in Brazil, undated; and 3. A collection of "University of Minnesota Flight Data on Skyhook Balloons" compiled by General Mills' Aeronautical Research Laboratories and dated October 16, 1950.

The collection in Box 1 also contains materials related to the 1988 University of Minnesota Symposium on the "Cosmic Abundance of Matter," which celebrated the fortieth anniversary of the discovery of the cosmic ray nuclei. Papers given by Phyllis Freier and Edward Ney are included.


  • Creation: 1948-1990.

Language of Materials


Use of materials:

Items in this collection do not circulate and may be used in-house only.


Requests for permission to quote P.S. Freier should be arranged with University of Minnesota Archives head.

Biographical note

Phyllis St. Cyr was born in Minneapolis, Minnesota, on January 21, 1921, and spent nearly her entire career at the University of Minnesota. After receiving B. S. and M. A. Degrees she married fellow physicist George Freier and worked at the Naval Ordnance Laboratory in Washington D. C. during World War II.

Following the war the Freiers returned to the University of Minnesota where she resumed graduate studies in physics. As a doctoral student she worked with Edward Ney and Frank Oppenheimer in the study of cosmic rays using high altitude balloons. Their experiment of April 21, 1948, provided data from which Phyllis Freier became the first person to see tracks in nuclear emulsions that proved that cosmic rays from outer space included nuclei of heavy elements. The paper based on these findings was published July 15, 1948 and became a classic in the field.

After she received her Ph.D. in 1950 Freier continued at the University as a Research Associate because the nepotism policy of the time prevented her from joining a department in which her husband taught. Despite this obstacle she established an international reputation in the field of cosmic ray physics while she ran a major nuclear emulsion laboratory.

In 1970 after nepotism rules relaxed, the University appointed her an Associate Professor; and in 1973 she achieved the rank of Professor. She continued her research and gained a reputation as an outstanding teacher. She also served on the board of the American Physical Society's Committee on the Status of Women in Physics from 1984-1986. From 1973 to 1976 she served on the University of Minnesota Senate Judicial Committee, which she chaired in 1975-1976. Her work focused improving procedures for faculty grievances.

Phyllis Freier retired from the University in December, 1990, and died at her St. Anthony Park home on December 18, 1992.


2 boxes


The collection consists of correspondence, research data, and class materials of Phyllis St. Cyr Freier, long associated with the University of Minnesota Department of Physics and Astronomy

Source of acquisition:

Donated to University of Minnesota Archives by the Freier family and the University of Minnesota Department of Physics.

Related Materials in University Archives

Edward Purdey Ney papers

Alfred O.C. Nier papers

Frank Oppenheimer papers

Jean Piccard papers

University of Minnesota. Senate. Judicial Committee papers

Processing information:

Collection processed by Carol E. Jenson with funds granted by the Center for the History of Physics, American Institute of Physics.

Inventory of the Phyllis St. Cyr Freier Papers, 1948-1990
Carol E. Jenson
Language of description
Script of description
Language of description note

Collecting Area Details

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