Search for possible solar influences in Ra-226 decays
Measurements of Ra-226 activity from eight HPGe gamma ray detectors at the NC State University PULSTAR Reactor were analyzed for evidence of periodic variations, with particular attention to annual variations. All measurements were made using the same reference source, and data sets were of varying...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2017-01-01
|
| Series: | Results in Physics |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211379716307987 |
| _version_ | 1811266910302502912 |
|---|---|
| author | Daniel D. Stancil Sümeyra Balci Yegen David A. Dickey Chris R. Gould |
| author_facet | Daniel D. Stancil Sümeyra Balci Yegen David A. Dickey Chris R. Gould |
| author_sort | Daniel D. Stancil |
| collection | DOAJ |
| description | Measurements of Ra-226 activity from eight HPGe gamma ray detectors at the NC State University PULSTAR Reactor were analyzed for evidence of periodic variations, with particular attention to annual variations. All measurements were made using the same reference source, and data sets were of varying length taken over the time period from September 1996 through August 2014. Clear evidence of annual variations was observed in data from four of the detectors. Short time periodograms from the data sets suggest temporal variability of both the amplitude and frequency of these variations. The annual variations in two of the data sets show peak values near the first of February, while surprisingly, the annual variations in the other two are roughly out of phase with the first two. Three of the four detectors exhibited annual variations over approximately the same time period. A joint statistic constructed by combining spectra from these three shows peaks approximating the frequencies of solar r-mode oscillations with νR = 11.74 cpy, m = 1, and l = 3, 5, 6. The fact that similar variations were not present in all detectors covering similar time periods rules out variations in activity as the cause, and points to differing sensitivities to unspecified environmental parameters instead. In addition to seasonal variations, the modulation of environmental parameters by solar processes remains a possible explanation of periodogram features, but without requiring new physics. Keywords: Nuclear beta decay, Solar oscillation modes, Time Series Analysis |
| first_indexed | 2024-04-12T20:51:51Z |
| format | Article |
| id | doaj.art-bc9452fe15394d59be2720e0372e6ea7 |
| institution | Directory Open Access Journal |
| issn | 2211-3797 |
| language | English |
| last_indexed | 2024-04-12T20:51:51Z |
| publishDate | 2017-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Physics |
| spelling | doaj.art-bc9452fe15394d59be2720e0372e6ea72022-12-22T03:17:07ZengElsevierResults in Physics2211-37972017-01-017385406Search for possible solar influences in Ra-226 decaysDaniel D. Stancil0Sümeyra Balci Yegen1David A. Dickey2Chris R. Gould3Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, NC 27695, United States; Corresponding author.Department of Physics, North Carolina State University, Raleigh, NC 27695, United StatesDepartment of Statistics, North Carolina State University, Raleigh, NC 27695, United StatesDepartment of Physics, North Carolina State University, Raleigh, NC 27695, United StatesMeasurements of Ra-226 activity from eight HPGe gamma ray detectors at the NC State University PULSTAR Reactor were analyzed for evidence of periodic variations, with particular attention to annual variations. All measurements were made using the same reference source, and data sets were of varying length taken over the time period from September 1996 through August 2014. Clear evidence of annual variations was observed in data from four of the detectors. Short time periodograms from the data sets suggest temporal variability of both the amplitude and frequency of these variations. The annual variations in two of the data sets show peak values near the first of February, while surprisingly, the annual variations in the other two are roughly out of phase with the first two. Three of the four detectors exhibited annual variations over approximately the same time period. A joint statistic constructed by combining spectra from these three shows peaks approximating the frequencies of solar r-mode oscillations with νR = 11.74 cpy, m = 1, and l = 3, 5, 6. The fact that similar variations were not present in all detectors covering similar time periods rules out variations in activity as the cause, and points to differing sensitivities to unspecified environmental parameters instead. In addition to seasonal variations, the modulation of environmental parameters by solar processes remains a possible explanation of periodogram features, but without requiring new physics. Keywords: Nuclear beta decay, Solar oscillation modes, Time Series Analysishttp://www.sciencedirect.com/science/article/pii/S2211379716307987 |
| spellingShingle | Daniel D. Stancil Sümeyra Balci Yegen David A. Dickey Chris R. Gould Search for possible solar influences in Ra-226 decays Results in Physics |
| title | Search for possible solar influences in Ra-226 decays |
| title_full | Search for possible solar influences in Ra-226 decays |
| title_fullStr | Search for possible solar influences in Ra-226 decays |
| title_full_unstemmed | Search for possible solar influences in Ra-226 decays |
| title_short | Search for possible solar influences in Ra-226 decays |
| title_sort | search for possible solar influences in ra 226 decays |
| url | http://www.sciencedirect.com/science/article/pii/S2211379716307987 |
| work_keys_str_mv | AT danieldstancil searchforpossiblesolarinfluencesinra226decays AT sumeyrabalciyegen searchforpossiblesolarinfluencesinra226decays AT davidadickey searchforpossiblesolarinfluencesinra226decays AT chrisrgould searchforpossiblesolarinfluencesinra226decays |