Dr. Kerstin Perez is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at Columbia University. The current cosmological paradigm includes two significant and unknown entities called "dark matter" and "dark energy." The physics of the Universe is dominated by their presence even though their nature remains unknown. Current investigations into the identity of dark matter focus on finding entirely new massive particles. Many dark matter search experiments are currently planned or ongoing, and many of them are challenged by the large background signal from conventional astrophysical processes and a vast array of signatures that could indicate a dark matter interaction. This project, part of the General Antiparticle Spectrometer (GAPS) experiment, aims to characterize the dark matter by detecting the low-energy subatomic particles predicted to be created as dark matter particles self-annihilate in the halo of our Milky Way Galaxy. The postdoctoral fellow of this award will lead the commissioning of the detector system that would detect these particles in this project.
The strength of the GAPS experiment is that it promises to provide an essentially background-free signature of dark matter, and the anticipated measurements will probe large portions of the theoretical parameter spaces of both supersymmetry and extra-dimensional theories, the leading models of dark matter production, and will complement and extend the reach of current experiments. Layers of semiconducting Si(Li) tracking detectors with excellent time and energy resolution are essential to the success of the GAPS detection and background rejection scheme. GAPS will utilize over 1000 of these detectors, and thus a consistent procedure for qualification and calibration will be the bridge between the ideal experimental design and its final performance. The fellow will spearhead the analysis of data from a prototype balloon flight and will lead the commissioning and calibration of these detectors.
The broader impacts of this project include a significant educational component. The fellow will work with the Columbia University Double Discovery Center (DDC) to implement a laboratory course and mentoring program aimed at encouraging underrepresented students to pursue an education in a scientific field. The fellow will establish a laboratory science course for junior high school students with lessons based on research pursued by members of the Columbia University community. A key aspect of this course will be to confront students' preconceived notions of where a science education leads by promoting interaction with role models from science backgrounds who have pursued a variety of professions.
The question of the origin of dark matter, the mysterious matter known to permeate the universe, looms over 21st-century astrophysics. Astronomical surveys and cosmological simulations have already ruled out the existence of enough heavy conventional objects to account for this "missing mass". Thus searches now focus on finding entirely new elementary particles. The General Antiparticle Spectrometer (GAPS) experiment aims to advance astro-particle searches for dark matter by detecting low-energy antideuterons (a nucleus containing an antiproton and antineutron) that result from dark matter interactions in the halo of our Milky Way Galaxy. Unlike many other particle signatures of dark matter, antideuterons have essentially zero standard astrophysical background. This signal many leading theoretical models of dark matter production, such as supersymmetry and extra dimensional theories, complementing and extending the reach of current experiments. Dr. Perez has used this award to lead the development of the lithium-drifted silicon (Si(Li)) tracking detectors that are essential to the success of the GAPS detection and background rejection scheme. GAPS will require over 10 square meters of these detectors; thus a low-cost fabrication procedure is necessary. Over the course of this award, Dr. Perez has produced the first functioning prototype Si(Li) detectors, eventually honing the process to deliver the energy resolution required for the GAPS experiment. She also used data from the prototype GAPS balloon flight, launched from Taiki, Japan in June 2012, to validate the detector cooling scheme and detector performance in the flight environment. This represents the first time in almost 50 years that large-scale Si(Li) production is feasible in a non-commercial environment. Dr. Perez has also worked with the Columbia University Double Discovery Center (DDC) to implement a laboratory course and mentoring program aimed at encouraging first-generation college-bound students to pursue an education in a scientific field. The DDC has provided academic guidance to low-income high school students in New York City since 1965. Within this framework, Dr. Perez piloted a Saturday morning class for 9-11th grade students, that brings to the classroom young graduate students, post-doctoral researchers, and professors from the Columbia University community to discuss their current field of research and to lead a short hands-on activity based on this field. A key aspect of this course is to confront students’ pre-conceived notions of where a science education leads by promoting interaction with role models with science backgrounds who have pursued a variety of professions. The course concludes with a career fair, in which students interact with and interview professionals in a variety of fields who have benefited from science education. The ultimate goal of this program has been to encourage students to view science education as a viable path towards a future career.
