C. Freeman
A5077655701- Solar and Space Plasma Dynamics
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Ionosphere and magnetosphere dynamics
- Atomic and Molecular Physics
- Radiation Therapy and Dosimetry
- Solar Radiation and Photovoltaics
- Astro and Planetary Science
- Nuclear physics research studies
- Radiation Effects in Electronics
- Neutrino Physics Research
- Advanced Radiotherapy Techniques
- Photocathodes and Microchannel Plates
- Mass Spectrometry Techniques and Applications
- Geomagnetism and Paleomagnetism Studies
- Atmospheric Ozone and Climate
University of Hawaii System
2020-2023
University of Hawaiʻi at Mānoa
2019-2020
Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca
2020
University of Pennsylvania
2010
The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station (ISS) conducting unique, long-duration mission of fundamental research in space. objectives include precise studies origin dark matter, antimatter, and cosmic rays as well exploration new phenomena. Following 16-year period construction testing, precursor flight Shuttle, AMS was installed ISS May 19, 2011. In this report we present results based 120 billion charged ray events up...
We report the observation of new properties primary iron (Fe) cosmic rays in rigidity range 2.65 GV to 3.0 TV with 0.62×106 nuclei collected by Alpha Magnetic Spectrometer experiment on International Space Station. Above 80.5 dependence ray Fe flux is identical He, C, and O fluxes, Fe/O ratio being constant at 0.155±0.006. This shows that unexpectedly belong same class which different from Ne, Mg, Si class.Received 2 October 2020Revised 22 November 2020Accepted 9 December...
We report the observation of new properties primary cosmic rays, neon (Ne), magnesium (Mg), and silicon (Si), measured in rigidity range 2.15 GV to 3.0 TV with 1.8×10^{6} Ne, 2.2×10^{6} Mg, 1.6×10^{6} Si nuclei collected by Alpha Magnetic Spectrometer experiment on International Space Station. The Ne Mg spectra have identical dependence above 3.65 GV. three 86.5 GV, deviate from a single power law 200 harden an way. Unexpectedly, rays is different He, C, O. This shows that O are two classes rays.
We present the precision measurement of daily proton fluxes in cosmic rays from May 20, 2011 to October 29, 2019 (a total 2824 days or 114 Bartels rotations) rigidity interval 1 100 GV based on 5.5×10^{9} protons collected with Alpha Magnetic Spectrometer aboard International Space Station. The exhibit variations multiple timescales. From 2014 2018, we observed recurrent flux a period 27 days. Shorter periods 9 and 13.5 are 2016. strength all three periodicities changes time rigidity....
We present the precision measurement of 2824 daily helium fluxes in cosmic rays from May 20, 2011 to October 29, 2019 rigidity interval 1.71 100 GV based on 7.6×10^{8} nuclei collected with Alpha Magnetic Spectrometer (AMS) aboard International Space Station. The flux and proton ratio exhibit variations multiple timescales. In nearly all time intervals 2014 2018, we observed recurrent a period 27 days. Shorter periods 9 days 13.5 are 2016. strength three periodicities changes rigidity....
We present the precision measurements of 11 years daily cosmic electron fluxes in rigidity interval from 1.00 to 41.9 GV based on 2.0×10^{8} electrons collected with Alpha Magnetic Spectrometer (AMS) aboard International Space Station. The exhibit variations multiple timescales. Recurrent flux periods 27 days, 13.5 and 9 days are observed. find that show distinctly different time proton fluxes. Remarkably, a hysteresis between is observed significance greater than 6σ at rigidities below 8.5...
Precise knowledge of the charge and rigidity dependence secondary cosmic ray fluxes secondary-to-primary flux ratios is essential in understanding propagation. We report properties heavy fluorine F R range 2.15 GV to 2.9 TV based on 0.29 million events collected by Alpha Magnetic Spectrometer experiment International Space Station. The spectrum deviates from a single power law above 200 GV. heavier F/Si ratio distinctly different lighter B/O (or B/C) dependence. In particular, 10 GV, F/SiB/O...
We report the properties of sodium (Na) and aluminum (Al) cosmic rays in rigidity range 2.15 GV to 3.0 TV based on 0.46 million 0.51 nuclei collected by Alpha Magnetic Spectrometer experiment International Space Station. found that Na Al, together with nitrogen (N), belong a distinct ray group. In this group, we observe that, similar N flux, both flux Al are well described sums primary component (proportional silicon flux) secondary fluorine flux). The fraction increases for N, Na, fluxes...
Abstract Interplanetary coronal mass ejections (ICMEs) are eruptions of plasma that propagate outward through the heliosphere. ICMEs, and shocks they drive, cause a sudden decrease in cosmic-ray flux their local area heliosphere, called Forbush (FD). A method defining FDs is established, an automated process for identifying neutron monitor (NM) data created. The correlation between ICME properties FD magnitude 12 different NMs examined 91 ICME-associated events occurring from 2001 2019...
Galactic cosmic rays (GCRs) entering the heliosphere are disturbed by magnetic field of Sun, which varies shape and intensity their local interstellar spectrum. The force-field approximation is a popular way dealing with solar modulation, especially for studies focused on galactic transport rays. validity this approach to reproduce modulated GCR fluxes at Earth tested using monthly proton measured PAMELA between July 2006 January 2014 helium AMS-02 May 2011 2017. We show that precision new...
This paper is intended as an initial study for quality assurance benefits from polymer gel detectors to proton therapy treatments. Several types were explored stability batch batch. The depth dose distributions in the gels examined with regard dependences and compared baseline measurements. results indicate may be able verify three dimensions along match line treatments
We study the predictions for p/He ratio in galactic cosmic rays according to force-field approximation. The dependence of time variation on local interstellar spectrum (LIS) shape and mass-to-charge ratio, $A/Z$, is analyzed detail. find that, depending rigidity range sign spectral index LIS can be correlated or anti-correlated with phase solar cycle. show that $A/Z$ most probable cause decrease recently observed by AMS-02 after 2015 between 2 3 GV.
Galactic cosmic rays (GCRs) entering the heliosphere are disturbed by magnetic field of Sun, which varies shape and intensity their local interstellar spectrum. The force-field approximation is a popular way dealing with solar modulation, especially for studies focused on galactic transport rays. validity this approach to reproduce modulated GCR fluxes at Earth tested using monthly proton measured PAMELA between July 2006 January 2014 helium AMS-02 May 2011 2017. We show that precision new...
We study the predictions for p/He ratio in galactic cosmic rays according to force-field approximation. The dependence of time variation on local interstellar spectrum (LIS) shape and mass-to-charge ratio, A/Z, is analyzed detail. find that, depending rigidity range sign spectral index LIS can be correlated or anti-correlated with phase solar cycle. show that A/Z most probable cause decrease recently observed by AMS-02 after 2015 between 2 3 GV.