Japanese Experiment Module Exposed Facility as an attached payload on August
22, 2017. Being above the atmosphere, it was not subject to the secondary particle
background that is inherent in stratospheric balloon experiments investigating the
origin of cosmic rays. ISS-CREAM took data from August 22, 2017 to February 12,
2019, with the long duration producing orders of magnitude greater statistics.
After decades of studying cosmic rays, scientist are learning that there is more
to learn. Why are there excesses of high-energy positrons? A lot of excitement was
generated by the possibility that this might be caused by the annihilation of dark
matter particles but other astrophysical explanations cannot be ruled out. In order
to characterize the excess, it will be necessary to extend precise measurements to
higher energies and to understand the processes by which cosmic rays propagate
and accelerate.
For a 3:39 minute NASA video, The Mystery of Cosmic Rays, go to:
https://youtu.be/_bKbMARsE- 4
For a 5:52 minute video narrated by Dr. Eun-Suk Seo of the CREAM VI launch
title “Beyond the Earth” go to:
https://cosmicray.umd.edu/images/stories/videos/cray_intro/High_Altitude_
Balloons.mp4
Antarctic Impulsive Transient Antenna (ANITA)
The ANITA balloon was described in Section 2.2 as a typical ZPB. In this section
we shall describe how the payloads improved our understanding neutrinos. It is a
radio telescope to detect ultra-high energy cosmic ray neutrinos during a balloon
flight over Antarctica. It is also the first NASA observatory for neutrinos of any kind.
Neutrinos are of great interest to astrophysicists. They are the only particles
that can reach Earth unattenuated at all energies. This is of particular interest at
high energies, where other particles and photons will interact with the photons of
the microwave background, preventing them from surviving over long astrophysical distances. In other words, if you want to see the ultra-high energy universe,
you should view it through the “light” of neutrinos. The Bible says, “we see
through the glass but darkly”.
The ANITA instrument detects these ultra-high energy neutrinos by way of the
Askaryan effect. This predicts the production of a coherent radio emission from
the cascade of particles produced in a high-energy particle interaction. In other
words it detects a “snap” in the radio frequencies arising from the interaction of
the ultra-high energy neutrino. In order to detect these Askaryan pulses, a radiotransparent medium is required in which the interaction can occur, and lots of it
because such interactions are rare. Radio transparent materials include salt, sand
and ice. And because the Askaryan pulses are very faint signals scientists need a
fairly radio-quiet location.
188 Accomplishments
22, 2017. Being above the atmosphere, it was not subject to the secondary particle
background that is inherent in stratospheric balloon experiments investigating the
origin of cosmic rays. ISS-CREAM took data from August 22, 2017 to February 12,
2019, with the long duration producing orders of magnitude greater statistics.
After decades of studying cosmic rays, scientist are learning that there is more
to learn. Why are there excesses of high-energy positrons? A lot of excitement was
generated by the possibility that this might be caused by the annihilation of dark
matter particles but other astrophysical explanations cannot be ruled out. In order
to characterize the excess, it will be necessary to extend precise measurements to
higher energies and to understand the processes by which cosmic rays propagate
and accelerate.
For a 3:39 minute NASA video, The Mystery of Cosmic Rays, go to:
https://youtu.be/_bKbMARsE- 4
For a 5:52 minute video narrated by Dr. Eun-Suk Seo of the CREAM VI launch
title “Beyond the Earth” go to:
https://cosmicray.umd.edu/images/stories/videos/cray_intro/High_Altitude_
Balloons.mp4
Antarctic Impulsive Transient Antenna (ANITA)
The ANITA balloon was described in Section 2.2 as a typical ZPB. In this section
we shall describe how the payloads improved our understanding neutrinos. It is a
radio telescope to detect ultra-high energy cosmic ray neutrinos during a balloon
flight over Antarctica. It is also the first NASA observatory for neutrinos of any kind.
Neutrinos are of great interest to astrophysicists. They are the only particles
that can reach Earth unattenuated at all energies. This is of particular interest at
high energies, where other particles and photons will interact with the photons of
the microwave background, preventing them from surviving over long astrophysical distances. In other words, if you want to see the ultra-high energy universe,
you should view it through the “light” of neutrinos. The Bible says, “we see
through the glass but darkly”.
The ANITA instrument detects these ultra-high energy neutrinos by way of the
Askaryan effect. This predicts the production of a coherent radio emission from
the cascade of particles produced in a high-energy particle interaction. In other
words it detects a “snap” in the radio frequencies arising from the interaction of
the ultra-high energy neutrino. In order to detect these Askaryan pulses, a radiotransparent medium is required in which the interaction can occur, and lots of it
because such interactions are rare. Radio transparent materials include salt, sand
and ice. And because the Askaryan pulses are very faint signals scientists need a
fairly radio-quiet location.
188 Accomplishments