ENTRY C1589 20160629 C160C158900000001 SUBENT C1589001 20160629 C160C158900100001 BIB 9 23 C158900100002 TITLE The 12C(alpha,gamma)16O reaction and stellar helium C158900100003 burning C158900100004 AUTHOR (P.Dyer,C.A.Barnes) C158900100005 REFERENCE (J,NP/A,233,(2),495,1974) C158900100006 #doi:10.1016/0375-9474(74)90470-9 C158900100007 INSTITUTE (1USACAL) C158900100008 FACILITY (VDGT,1USACAL) ONR-CIT tandem accelerator. C158900100009 PART-DET (G) C158900100010 SAMPLE (6-C-12,ENR=0.99945) All targets used in the present C158900100011 experiment were made by the thermal cracking of C158900100012 methyl iodide by means of an electric current passed C158900100013 through a 0.008 cm thick tantalum strip; when the C158900100014 strip is heated, the methyl iodide decomposes, and a C158900100015 layer of elemental carbon is deposited on the strip. C158900100016 The methyl iodide was prepared from two different C158900100017 samples of 12C. The first target had the 13C content C158900100018 of the elemental carbon targets prepared from this C158900100019 material was about 0.1 %. The second target the C158900100020 starting material for the targets was methyl alcohol, C158900100021 in which the 13C/C ratio was believed to be <50 parts C158900100022 per million. C158900100023 DETECTOR (NAICR) Two 20.3 cm diameter by 12.7 cm long crystals. C158900100024 HISTORY (20160629C) BP C158900100025 ENDBIB 23 0 C158900100026 NOCOMMON 0 0 C158900100027 ENDSUBENT 26 0 C158900199999 SUBENT C1589002 20160629 C160C158900200001 BIB 5 27 C158900200002 REACTION (6-C-12(A,G)8-O-16,PAR,SIG) electric dipole, E1, cross C158900200003 sections. C158900200004 METHOD (PHD) The angular distribution measurements were used C158900200005 to separate the observed ground state gamma-radiation C158900200006 into El and E2 components, on the assumption that the C158900200007 E2 radiation has the energy dependence to be expected C158900200008 for direct E2 radiative capture. The angular C158900200009 distributions thus determine a normalization for the C158900200010 strength of the E2 capture, and the calculated E2 C158900200011 radiation components were subtracted from the C158900200012 observed yields at those energies for which angular C158900200013 distribution measurements were not possible because C158900200014 of low intensity. C158900200015 ANALYSIS (PGS) The first step in the extraction of the 160 C158900200016 ground-state gamma-ray yields from the two-dimensional C158900200017 spectra was to identify a rectangular region-of- C158900200018 interest in the time energy (pulse-height) plane. The C158900200019 background spectrum was normalized to the 12C C158900200020 spectrum according to the height of the prompt C158900200021 neutron peak and the magnitude of the C158900200022 time-independent background, and was then subtracted C158900200023 from the 12C spectrum to obtain the gamma-ray yield. C158900200024 ERR-ANALYS (DATA-ERR) The errors shown are derived from the C158900200025 statistical errors on the 90 degrees gamma-ray yields C158900200026 and from the uncertainties in the strength of the E2 C158900200027 radiation. C158900200028 STATUS (TABLE) Table 2, page 514. C158900200029 ENDBIB 27 0 C158900200030 COMMON 3 3 C158900200031 E-LVL E-LVL EN-RSL C158900200032 MEV MEV KEV C158900200033 7.12 9.60 15.0 C158900200034 ENDCOMMON 3 0 C158900200035 DATA 3 24 C158900200036 EN-CM DATA DATA-ERR C158900200037 MEV NB NB C158900200038 1.41 0.29 0.10 C158900200039 1.50 0.64 0.14 C158900200040 1.64 1.09 0.17 C158900200041 1.73 1.71 0.60 C158900200042 1.79 2.09 0.40 C158900200043 1.81 2.49 0.25 C158900200044 1.87 2.93 0.31 C158900200045 1.87 3.25 0.50 C158900200046 1.95 4.92 0.40 C158900200047 1.96 3.90 0.60 C158900200048 2.03 7.04 0.60 C158900200049 2.04 8.34 0.65 C158900200050 2.08 9.10 0.60 C158900200051 2.11 14.17 0.70 C158900200052 2.15 16.13 1.30 C158900200053 2.18 19.50 0.81 C158900200054 2.26 29.91 1.01 C158900200055 2.32 39.53 1.31 C158900200056 2.42 37.06 1.61 C158900200057 2.49 31.23 1.22 C158900200058 2.56 20.98 1.33 C158900200059 2.78 8.41 0.73 C158900200060 2.86 6.66 0.70 C158900200061 2.94 5.69 0.75 C158900200062 ENDDATA 26 0 C158900200063 ENDSUBENT 62 0 C158900299999 SUBENT C1589003 20160629 C160C158900300001 BIB 4 11 C158900300002 REACTION (6-C-12(A,G)8-O-16,,SIG,,SFC) C158900300003 ANALYSIS A three-level R-matrix parametrization. C158900300004 ERR-ANALYS (DATA-ERR) The errors in the S-factor were determined C158900300005 by observing the range of variation of S(0.3 MeV, C158900300006 c.m.) over a contour of chi2 corresponding to one C158900300007 standard deviation error (minimum chi2 plus the C158900300008 number of degrees of freedom), which was traced out C158900300009 as a function of the parameters varied in the fit to C158900300010 the 12C(alpha,gamma)160 data. C158900300011 STATUS (DEP,C1589002) C158900300012 (TABLE) page 516. C158900300013 ENDBIB 11 0 C158900300014 NOCOMMON 0 0 C158900300015 DATA 4 1 C158900300016 EN-CM DATA +DATA-ERR -DATA-ERR C158900300017 MEV B*MEV B*MEV B*MEV C158900300018 0.3 0.14 0.14 0.12 C158900300019 ENDDATA 3 0 C158900300020 ENDSUBENT 19 0 C158900399999 SUBENT C1589004 20160629 C160C158900400001 BIB 4 10 C158900400002 REACTION (6-C-12(A,G)8-O-16,,SIG,,SFC) C158900400003 ANALYSIS A hybrid R-matrix optical-model parameterization. C158900400004 ERR-ANALYS (DATA-ERR) The error assigned to S(0.3 MeV, c.m.) C158900400005 includes the statistical error (obtained from chi2 C158900400006 contours), an error for a change in channel radius of C158900400007 +0.6 fm, and an error for a +20 keV shift in the C158900400008 relative energy scale of the 12C(alpha,alpha)12C and C158900400009 12C(alpha,gamma)160 data. C158900400010 STATUS (DEP,C1589002) C158900400011 (TABLE) page 517. C158900400012 ENDBIB 10 0 C158900400013 NOCOMMON 0 0 C158900400014 DATA 4 1 C158900400015 EN-CM DATA +DATA-ERR -DATA-ERR C158900400016 MEV B*MEV B*MEV B*MEV C158900400017 0.3 0.08 0.05 0.04 C158900400018 ENDDATA 3 0 C158900400019 ENDSUBENT 18 0 C158900499999 ENDENTRY 4 0 C158999999999