ENTRY O1606 20070516 O030O160600000001 SUBENT O1606001 20070516 O030O160600100001 BIB 13 70 O160600100002 TITLE Subbarrrier fusion of O-16+Sm-147,149. O160600100003 AUTHOR (D.E.Digregorio, M.Ditada, D.Abriola, M.Elgue, O160600100004 A.Etchegoyen, M.C.Etchegoyen, J.O.Fernandez Niello, O160600100005 A.M.J.Ferrero, S.Gil, A.O.Macchiavelli, A.J.Pacheco, O160600100006 J.E.Testoni, P.R.Silveira Gomes, V.R.Vanin, O160600100007 R.Liguori Neto, E.Crema, R.G.Stokstad) O160600100008 INSTITUTE (3ARGCNE) O160600100009 (3BZLUFF) O160600100010 (3BZLUSP) O160600100011 (1USALRL) O160600100012 REFERENCE (J,PR/C,39,516,1989) O160600100013 HISTORY (20070511C) S B O160600100014 (20070516U) Last checking has been done. O160600100015 SAMPLE Targets of isotopically enriched Sm-147 98% and Sm-149 O160600100016 97.4% with thicknesses of 40-mug/cm**2 and O160600100017 125-mug/cm**2, respectively, evaporated onto thin O160600100018 carbon backings were used. O160600100019 The Yb-evaporation residues were trapped in an Al-foil O160600100020 of 800-mug/cm**2, which was placed 2-mm behind the O160600100021 samarium target. The thickness of the catcher foil was O160600100022 sufficient to stop the evaporation residues letting O160600100023 through the products of the reaction of O-16 with the O160600100024 oxygen impurity in the target, with the carbon of the O160600100025 target backing and with the aluminium of the some O160600100026 catcher foil. During selected runs a second catcher O160600100027 foil was located behind the first one in order to O160600100028 verify that none of the evaporation residues was lost. O160600100029 ADD-RES (COMP).Statistical model calculations of the x-n O160600100030 distributions. O160600100031 FACILITY (VDGT,3ARGCNE) The 20-UD tandem accelerator at the O160600100032 tandar-laboratory in Buenos Aires. O160600100033 DETECTOR (SIBAR) Two surface barrier silicon counters were O160600100034 placed at +-30-degree to the beam and at a distance O160600100035 of 31-cm from the target for monitoring the elastic andO160600100036 inelastic scattering of O-16 with the samarium O160600100037 isotopes. O160600100038 Following irradiations of about 100-120 min, the O160600100039 catcher foils were removed from the scattering chamber O160600100040 and placed in front of a 5-cm**3 Ge-planar X-ray O160600100041 detector. The X-ray detector had an energy resolution O160600100042 of 480-eV(FWHM) at 50-KeV. The absolute photopeak O160600100043 efficiency of the detector was determined using a set O160600100044 of calibrated sources that were carefully mounted in O160600100045 the same geometry as the catcher foils. The efficiencyO160600100046 was 3.7+-1.2% at an energy of 40-60-KeV. O160600100047 CORRECTION *By authors*.Corrections were made for summing effects O160600100048 due to the simultaneous detection of more than one O160600100049 photon. O160600100050 METHOD (SITA) O160600100051 ERR-ANALYS (ERR-1).The error from the absolute normalization basedO160600100052 on rutherford scattering is 9%. O160600100053 (ERR-2).The error from the absolute efficiency of the O160600100054 X-ray detector is 5%. O160600100055 (ERR-3).The error in the coefficients of expression O160600100056 is 10%. O160600100057 (ERR-4).The error on the cross section arising from theO160600100058 statistical uncertainty in the peak areas and the O160600100059 fitting of the decay curves. There error were typicallyO160600100060 5%. O160600100061 (ERR-T).By summing in quadrature the different sources O160600100062 of error (see above), excluding beam energy an overall O160600100063 error of approx. 12% in the fusion cross sections was O160600100064 calculated. The errors are higher 15-20% at lowest O160600100065 bombarding energies, where the counting statistics wereO160600100066 lower. See table 2. O160600100067 (EN-ERR).The absolute energy of the O-16 beam has an O160600100068 uncertainty of +-0.5%, which has been determined by O160600100069 calibrating the 90-degree analyzing magnet of the O160600100070 tandem accelerator . O160600100071 STATUS (TABLE) In paper O160600100072 ENDBIB 70 0 O160600100073 COMMON 5 3 O160600100074 EN-ERR ERR-1 ERR-2 ERR-3 ERR-4 O160600100075 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT O160600100076 0.5 9. 5. 10. 5. O160600100077 ENDCOMMON 3 0 O160600100078 ENDSUBENT 77 0 O160600199999 SUBENT O1606002 20070516 O030O160600200001 BIB 2 14 O160600200002 REACTION (62-SM-147(8-O-16,FUS),,SIG) O160600200003 COMMENT *By authors* the different isotopic contributions, O160600200004 expressed as a percentage of the fusion cross sections,O160600200005 see below- O160600200006 xn and a-xn distribution(%) O160600200007 en(MeV) 2N 3N 4N a-xn O160600200008 Sm-147 74.9 4. 82. 6. 8. O160600200009 70.5 14. 78. 2. 6. O160600200010 66.9 30. 70. O160600200011 65.9 37. 63. O160600200012 65.0 43. 57. O160600200013 64.0 78. 22. O160600200014 62.9 83. 17. O160600200015 62.0 99. 1. O160600200016 ENDBIB 14 0 O160600200017 NOCOMMON 0 0 O160600200018 DATA 3 8 O160600200019 EN DATA ERR-T O160600200020 MEV MB MB O160600200021 74.9 404. 48. O160600200022 70.5 210. 25. O160600200023 66.9 69. 8. O160600200024 65.9 47.3 5.7 O160600200025 65. 27.3 3.3 O160600200026 64. 7.6 1.2 O160600200027 62.9 2.8 0.4 O160600200028 62. 0.52 0.1 O160600200029 ENDDATA 10 0 O160600200030 ENDSUBENT 29 0 O160600299999 SUBENT O1606003 20070516 O030O160600300001 BIB 2 17 O160600300002 REACTION (62-SM-148(8-O-16,FUS),,SIG) O160600300003 COMMENT *By authors* the different isotopic contributions, O160600300004 expressed as a percentage of the fusion cross sections,O160600300005 see below- O160600300006 xn and a-xn distribution(%) O160600300007 en(MeV) 2N 3N 4N a-xn O160600300008 Sm-148 74.9 2. 69. 18. 11. O160600300009 69.9 11. 75. 5. 9. O160600300010 67.8 17. 75. 2. 6. O160600300011 65.9 28. 72. O160600300012 64.0 51. 49. O160600300013 62.8 54. 46. O160600300014 60.9 83. 17. O160600300015 * By authors*.The cross sections for O-16+Sm-148 were O160600300016 measured in order to have a precise determination of O160600300017 the relative shapes of the excitation functions for O160600300018 the odd and adjacent even isotopes samarium. O160600300019 ENDBIB 17 0 O160600300020 NOCOMMON 0 0 O160600300021 DATA 3 7 O160600300022 EN DATA ERR-T O160600300023 MEV MB MB O160600300024 74.9 463. 56. O160600300025 69.9 213. 26. O160600300026 67.8 120. 14. O160600300027 65.9 42.2 5.1 O160600300028 64. 13.9 2.1 O160600300029 62.8 4.7 0.7 O160600300030 60.9 0.5 0.1 O160600300031 ENDDATA 9 0 O160600300032 ENDSUBENT 31 0 O160600399999 SUBENT O1606004 20070516 O030O160600400001 BIB 2 16 O160600400002 REACTION (62-SM-149(8-O-16,FUS),,SIG) O160600400003 COMMENT *By authors* the different isotopic contributions, O160600400004 expressed as a percentage of the fusion cross sections,O160600400005 see below- O160600400006 xn and a-xn distribution(%) O160600400007 en(MeV) 2N 3N 4N a-xn O160600400008 Sm-149 75.0 54. 36. 10. O160600400009 70.5 3. 81. 10. 7. O160600400010 68.0 5. 87. 5. 3. O160600400011 66.0 7. 89. O160600400012 65.0 10. 90. O160600400013 64.0 15. 85. O160600400014 63.0 21. 79. O160600400015 62.0 35. 65. O160600400016 61.5 40. 60. O160600400017 61.0 45. 55. O160600400018 ENDBIB 16 0 O160600400019 NOCOMMON 0 0 O160600400020 DATA 3 10 O160600400021 EN DATA ERR-T O160600400022 MEV MB MB O160600400023 75. 460. 55. O160600400024 70. 191. 23. O160600400025 68. 127. 15. O160600400026 66. 56.6 6.8 O160600400027 64.9 32.6 3.9 O160600400028 63.9 15.4 1.8 O160600400029 63. 7. 1.1 O160600400030 62. 3. 0.5 O160600400031 61.5 1.9 0.4 O160600400032 61. 0.63 0.13 O160600400033 ENDDATA 12 0 O160600400034 ENDSUBENT 33 0 O160600499999 ENDENTRY 4 0 O160699999999