Dr. H. Pieter Mumm (ORCiD) is a physicist in the Neutron Physics Group at the National Institute of Standards and Technology. Dr. Mumm believes that robust science leverages a diversity of activities and indeed his research spans precision neutron metrology, detector development, and probes of our fundamental understanding of the laws of nature. To test the foundation of particle physics, the Standard Model, Dr. Mumm has performed several precision measurements including a test of time-reversal invariance in neutron beta decay that shed light on the matter-antimatter asymmetry of the universe, a first observation of neutron radiative decay, and a precision measurement of the neutron lifetime using entirely new methods to trap and study these simple building blocks of matter. Dr. Mumm is currently involved in a measurement of the neutron lifetime that counts decay protons from a cold neutron beam with a precisely determined flux. Dr. Mumm is co-spokeperson for the PROSPECT experiment which has recently made a high precision measurement of possible changes in antineutrino energy spectrum with distance from a reactor. With these measurements, PROSPECT will continue to address anomalies found in previous reactor antineutrinos experiments that hinted at the exciting possible existence of an entirely new particle, a so-called sterile neutrino. Dr. Mumm is an executive officer for Nu Tools, a study aimed at understanding the utility of neutrino detectors for a variety of applied purposes that was in part motived by the success of neutrino detectors like PROSPECT.
As part of his calibration and detector development efforts, Dr. Mumm currently performs precise measurements of neutron source intensities using a neutron absorbing manganese bath. Improvements in this technique will reduce the uncertainty of neutron source calibrations for basic science, industry, and government. Dr. Mumm is also involved in efforts to improve techniques for neutron detection and spectroscopy. This work builds on segmented spectrometers and the principle of capture-gating to provide energy information while greatly suppressing backgrounds. Such spectrometers can be used for applications including the characterization of low-activity neutron sources and flux and spectrum measurements of fast neutrons in a variety of environments.
Dr. Mumm received a B.S. in Physics from the University of California at Berkeley and a Ph.D. in Physics from the University of Washington. He began his career at NIST as a National Research Council (NRC) postdoctoral fellow followed by a postdoctoral position at the University of Maryland. He became a NIST staff scientist in 2008. He currently holds a position as an Adjunct Associate Professor of Physics at the University of Maryland. Dr. Mumm has mentored several staff scientists, graduate students and more than a dozen undergraduate and high-school students. He has served on many review panels for the Department of Energy. Dr. Mumm and the PROSPECT team won a Department of Commerce Silver Medal in 2019.