Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction
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Ohio University / OhioLINK
2009
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1230079038 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-ohiou12300790382021-08-03T05:45:57Z Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction Adekola, Aderemi S. Nuclear Physics proton-transfer reaction proton width reaction rate unbound levels around proton threshold in <sup>19</sup>Ne astrophysical S-factor <p>The nuclear structure of <sup>19</sup>Ne near the proton threshold is of interest for understanding the rates of proton-induced reactions on <sup>18</sup>F in novae. Analogues for several states in the mirror nucleus <sup>19</sup>F have not yet been identified in <sup>19</sup>Ne, indicating the level structure of <sup>19</sup>Ne in this region is incomplete. The proton-transfer reaction <sup>18</sup>F(<i>d,n</i>)<sup>19</sup>Ne and neutron-transfer reaction <sup>18</sup>F(<i>d,p</i>)<sup>19</sup>F have been measured simultaneously at E<sub>c.m.</sub> = 14.9 MeV. The experiments were performed at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL) by bombarding a 720-µg/cm<sup>2</sup> CD<sub>2</sub> target with a radioactive <sup>18</sup>F beam. The <sup>19</sup>Ne ions of interest are highly excited and promptly decay by breakup into α and <sup>15</sup>O particles. The same holds true for states in <sup>19</sup>F which decay into α and <sup>15</sup>N particles. These charged particles were detected in coincidence in position-sensitive E – ΔE silicon telescopes. Particle identification, coincidence, and <i>Q</i>-value requirements enable us to distinguish the reaction of interest from other reactions. The reconstruction of relative energy of the detected particles reveals the excited states of <sup>19</sup>Ne and <sup>19</sup>F which are populated. </p><p>We have observed fifteen <sup>19</sup>Ne levels from the <sup>18</sup>F(<i>d,n</i>)<sup>19</sup>Ne measurement with five levels below the proton threshold. Eighteen <sup>19</sup>F levels have been observed with the <sup>18</sup>F(<i>d,p</i>)<sup>19</sup>F measurement. Angular distributions were extracted for all the levels observed in both nuclei and converted to differential cross sections using all necessary normalizing parameters. However, Distorted Wave Born Approximation (DWBA) calculations of the differential cross section were only done for levels with enough statistics to allow a meaningful comparison to the calculation. The spectroscopic factors determined from this analysis for these levels are reported. </p><p>The R-matrix analysis of the <sup>18</sup>F(<i>p,α</i>)<sup>15</sup>O reaction, taking into the account new information from this experiment as well as other recent measurements indicate that the astrophysical S-factoris considerably less than than previously thought by about a factor of 2 - 5 within the temperature range of typical nova. The astrophysical S-factor was numerically integrated to produce an improved <sup>18</sup>F(<i>p,α</i>)<sup>15</sup>O reaction rate. The uncertainty on the <sup>18</sup>F(<i>p,α</i>)<sup>15</sup>O reaction rate due to interference between the 3/2<sup>+</sup> resonances is found to have been reduced when compared to the most recent work of Chae <i>et al</i>.</p> 2009-04-23 English text Ohio University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1230079038 http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1230079038 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Nuclear Physics proton-transfer reaction proton width reaction rate unbound levels around proton threshold in <sup>19</sup>Ne astrophysical S-factor |
| spellingShingle |
Nuclear Physics proton-transfer reaction proton width reaction rate unbound levels around proton threshold in <sup>19</sup>Ne astrophysical S-factor Adekola, Aderemi S. Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction |
| author |
Adekola, Aderemi S. |
| author_facet |
Adekola, Aderemi S. |
| author_sort |
Adekola, Aderemi S. |
| title |
Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction |
| title_short |
Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction |
| title_full |
Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction |
| title_fullStr |
Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction |
| title_full_unstemmed |
Proton-transfer Study of Unbound <sup>19</sup>Ne States via <sup>2</sup>H(<sup>18</sup>F,<i>α</i>+<sup>15</sup>O)<i>n</i> Reaction |
| title_sort |
proton-transfer study of unbound <sup>19</sup>ne states via <sup>2</sup>h(<sup>18</sup>f,<i>α</i>+<sup>15</sup>o)<i>n</i> reaction |
| publisher |
Ohio University / OhioLINK |
| publishDate |
2009 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1230079038 |
| work_keys_str_mv |
AT adekolaaderemis protontransferstudyofunboundsup19supnestatesviasup2suphsup18supfiaisup15supoinireaction |
| _version_ |
1719424926978408448 |