ENTRY O0878 20051125 O025O087800000001 SUBENT O0878001 20051125 O025O087800100001 BIB 14 56 O087800100002 TITLE Cross section for 170 degrees backscattering of 0.8- O087800100003 2.7-MeV proton from magnesium and sulfur. O087800100004 AUTHOR (E.Rauhala, M.Luomajarvi) O087800100005 INSTITUTE (2SF HLS) O087800100006 REFERENCE (J,NIM/B,33,628,1988) O087800100007 HISTORY (20010614C) O087800100008 (20051125A) REACTION Lines are corrected O087800100009 (20051125U) Last checking has been done. O087800100010 SAMPLE Two targets containing natural sulfur and magnesium O087800100011 were used. The former one consisted of a 2.5*10e+18 O087800100012 atoms/ cm**2 layer of Zn-S on aluminium backing, the O087800100013 latter of a 92*10E+15 atoms/cm**2 gold film evaporated O087800100014 onto a thick magnesium substrate. The thickness of theO087800100015 Zn-S layer corresponds to 16 KeV energy loss for 2.4 O087800100016 MeV protons. The 1:1 stoichiometry of the Zn-S was O087800100017 verified, and the areal densities of the Au and Zn-S O087800100018 films were determined several times during the O087800100019 measurements by 2-MeV He-4 ion backscattering. In the O087800100020 case of the Au/mg sample, the number of Au atoms/cm**2 O087800100021 was obtained, using the Au yield relative to the yield O087800100022 from the bulk mg of the same sample. O087800100023 PART-DET (A) O087800100024 DETECTOR (SIBAR) O087800100025 FACILITY (VDG,2SF HLS) Van de Graaff accelerator of the O087800100026 University of Helsinki. O087800100027 METHOD (SITA) O087800100028 Two methods of deriving the scattering cross sections O087800100029 from the experimental data were employed. O087800100030 For the thin layer sample Zn-S is given by the ratio ofO087800100031 the total number of counts of the corresponding O087800100032 backscattering signals. O087800100033 For the thick mg sample, a simulated computer fit O087800100034 provided the cross sections using of the dependence O087800100035 between the ion collision energy as a function of O087800100036 depth, stopping and scattering cross sections. O087800100037 REL-REF (R,O0881001,E.RAUHALA,J,NIM/B,12,447,1985) ExperimentalO087800100038 method. O087800100039 ADD-RES Computer data analysis of proton backscattering from O087800100040 light elements has been studied. O087800100041 ERR-ANALYS The uncertainties in the cross section data results O087800100042 statistical errors and background subtraction for O087800100043 sulfur. In the case of mg, the inaccuracies due to O087800100044 possible errors in the proton and alpha particle O087800100045 stopping powers which are used in determining the O087800100046 relative backscatterig yields of mg and Au, also affectO087800100047 the cross section data.Consequently, except for the O087800100048 narrow resonances, the estimated standard error of the O087800100049 cross section data for sulfur is reduced from 3% to O087800100050 1.5% as the energy increases. The uncertainty for mg O087800100051 falls below 5%. It should be noted that the O087800100052 experimental data agree with the rutherford cross O087800100053 section curves within 1.5% for Mg below 800-KeV and forO087800100054 sulfur below 1600-KeV. O087800100055 (EN-ERR).The proton energy is calibrated with an O087800100056 accuracy of +-3-KeV. O087800100057 STATUS (TABLE) O087800100058 ENDBIB 56 0 O087800100059 COMMON 1 3 O087800100060 EN-ERR O087800100061 KEV O087800100062 3. O087800100063 ENDCOMMON 3 0 O087800100064 ENDSUBENT 63 0 O087800199999 SUBENT O0878002 20051125 O025O087800200001 BIB 1 1 O087800200002 REACTION (12-MG-0(P,EL)12-MG-0,,DA) O087800200003 ENDBIB 1 0 O087800200004 COMMON 1 3 O087800200005 ANG O087800200006 ADEG O087800200007 170. O087800200008 ENDCOMMON 3 0 O087800200009 DATA 2 59 O087800200010 EN DATA O087800200011 KEV MB/SR O087800200012 700. 385. O087800200013 800. 295. O087800200014 815. 243. O087800200015 820. 335. O087800200016 850. 277. O087800200017 900. 247. O087800200018 950. 222. O087800200019 1000. 205. O087800200020 1050. 186. O087800200021 1100. 169. O087800200022 1150. 156. O087800200023 1200. 146. O087800200024 1250. 133. O087800200025 1300. 123. O087800200026 1350. 114. O087800200027 1415. 109. O087800200028 1450. 100. O087800200029 1466. 95. O087800200030 1480. 140. O087800200031 1505. 90. O087800200032 1540. 83. O087800200033 1570. 68. O087800200034 1588. 45. O087800200035 1609. 24. O087800200036 1635. 125. O087800200037 1665. 94. O087800200038 1700. 93. O087800200039 1750. 91. O087800200040 1770. 89. O087800200041 1810. 80. O087800200042 1835. 81. O087800200043 1850. 80. O087800200044 1870. 77. O087800200045 1880. 75. O087800200046 1885. 80. O087800200047 1900. 81. O087800200048 1935. 67. O087800200049 1945. 77. O087800200050 1990. 76. O087800200051 2010. 84. O087800200052 2050. 130. O087800200053 2070. 105. O087800200054 2090. 92. O087800200055 2105. 80. O087800200056 2165. 82. O087800200057 2208. 69. O087800200058 2232. 72. O087800200059 2252. 66. O087800200060 2280. 65. O087800200061 2300. 78. O087800200062 2330. 59. O087800200063 2380. 56. O087800200064 2390. 62. O087800200065 2398. 75. O087800200066 2430. 49. O087800200067 2460. 60. O087800200068 2475. 56. O087800200069 2485. 50. O087800200070 2540. 56. O087800200071 ENDDATA 61 0 O087800200072 ENDSUBENT 71 0 O087800299999 SUBENT O0878003 20051125 O025O087800300001 BIB 1 1 O087800300002 REACTION (16-S-0(P,EL)16-S-0,,DA) O087800300003 ENDBIB 1 0 O087800300004 NOCOMMON 0 0 O087800300005 DATA 3 78 O087800300006 EN ANG DATA O087800300007 KEV ADEG MB/SR O087800300008 1500. 155. 160. O087800300009 1500. 170. 149. O087800300010 1550. 155. 150. O087800300011 1550. 170. 141. O087800300012 1600. 155. 145. O087800300013 1600. 170. 135. O087800300014 1650. 155. 133. O087800300015 1650. 170. 127. O087800300016 1700. 155. 126. O087800300017 1700. 170. 117. O087800300018 1750. 155. 118. O087800300019 1750. 170. 112. O087800300020 1800. 155. 109. O087800300021 1800. 170. 104. O087800300022 1830. 155. 106. O087800300023 1830. 170. 99. O087800300024 1850. 155. 100. O087800300025 1850. 170. 92. O087800300026 1870. 155. 91. O087800300027 1870. 170. 80. O087800300028 1885. 155. 74. O087800300029 1885. 170. 62. O087800300030 1895. 155. 49. O087800300031 1895. 170. 40. O087800300032 1900. 155. 100. O087800300033 1900. 170. 110. O087800300034 1905. 155. 165. O087800300035 1905. 170. 186. O087800300036 1915. 155. 146. O087800300037 1915. 170. 153. O087800300038 1925. 155. 127. O087800300039 1925. 170. 118. O087800300040 1940. 155. 113. O087800300041 1940. 170. 108. O087800300042 1965. 155. 101. O087800300043 1965. 170. 100. O087800300044 2000. 155. 95. O087800300045 2000. 170. 92. O087800300046 2050. 155. 88. O087800300047 2050. 170. 86. O087800300048 2100. 155. 83. O087800300049 2100. 170. 80. O087800300050 2150. 155. 76. O087800300051 2150. 170. 72. O087800300052 2200. 155. 66. O087800300053 2200. 170. 63. O087800300054 2250. 155. 54. O087800300055 2250. 170. 50. O087800300056 2280. 155. 44. O087800300057 2280. 170. 37. O087800300058 2300. 155. 32. O087800300059 2300. 170. 23. O087800300060 2315. 155. 18. O087800300061 2315. 170. 7. O087800300062 2325. 155. 22. O087800300063 2325. 170. 17. O087800300064 2340. 155. 52. O087800300065 2340. 170. 50. O087800300066 2350. 155. 72. O087800300067 2350. 170. 85. O087800300068 2360. 155. 84. O087800300069 2360. 170. 92. O087800300070 2380. 155. 86. O087800300071 2380. 170. 90. O087800300072 2400. 155. 85. O087800300073 2400. 170. 87. O087800300074 2450. 155. 79. O087800300075 2450. 170. 79. O087800300076 2500. 155. 70. O087800300077 2500. 170. 70. O087800300078 2550. 155. 64. O087800300079 2550. 170. 63. O087800300080 2600. 155. 74. O087800300081 2600. 170. 80. O087800300082 2650. 155. 56. O087800300083 2650. 170. 53. O087800300084 2690. 155. 46. O087800300085 2690. 170. 42. O087800300086 ENDDATA 80 0 O087800300087 ENDSUBENT 86 0 O087800399999 ENDENTRY 3 0 O087899999999