ENTRY 23184 20121016 22332318400000001 SUBENT 23184001 20121016 22332318400100001 BIB 15 79 2318400100002 TITLE Experimental and theoretical study of the (n,2n) 2318400100003 reaction on 174,176Hf isotopes. 2318400100004 AUTHOR (M.Serris, M.Diakaki, S.Galanopoulos, M.Kokkoris, 2318400100005 M.Lamprou, C.T.Papadopoulos, R.Vlastou, P.Demetriou, 2318400100006 C.A.Kalfas, A.Lagoyannis) 2318400100007 INSTITUTE (2GRCTUA) M.Diakaki, M.Kokkoris, M.Lamprou, 2318400100008 C.T.Papadopoulos, R.Vlastou. 2318400100009 (2GRCATH) P.Demetriou,C.A.Kalfas,A.Lagoyannis. 2318400100010 (2GRCGRC) Hellenic Army Academy, 16673 Vari, Athens, 2318400100011 Greece. M.Serris . 2318400100012 REFERENCE (J,PR/C,86,034602,2012) 2318400100013 #doi:10.1103/PhysRevC.86.034602 2318400100014 FACILITY (VDGT,2GRCATH) The 5.5 MV Van de Graaff tandem 2318400100015 accelerator of NCSR DEMOKRITOS. 2318400100016 INC-SOURCE (D-D) D2 gas target, deuteron beams with currents 2318400100017 about 1-2 microA. 2318400100018 INC-SPECT The quasimonoenergetic neutron beams were produced 2318400100019 with a neutron flux of about (2-4)x10**6 n/cm**2/sec. 2318400100020 The average effective flux on each sample was obtained 2318400100021 by taking the mean of the calculated flux values for 2318400100022 the front and back Al foils. 2318400100023 METHOD (ACTIV) The activation measurements involved continuous2318400100024 irradiation of the samples for about 48 h at each 2318400100025 neutron beam energy. 2318400100026 (STTA) 2318400100027 DETECTOR (HPGE) Two (80% and 85% relative efficiency) HPGe 2318400100028 detectors. 2318400100029 The absolute efficiency of the detectors was obtained 2318400100030 using a calibrated 152Eu source placed at the same 2318400100031 distance as the samples. Calibrated monoenergetic 2318400100032 sources 54Mn, 60Co, 56Co, 137Cs, 22Na were used at 2318400100033 distances of 28 and 7 cm from the detector front to 2318400100034 correct the 152Eu efficiency for summing effects, which2318400100035 did not exceed 6%. 2318400100036 The detectors were shielded with lead blocks covered 2318400100037 by Cd. 2318400100038 (BF3) BF3-counter for neutron beam flux variation 2318400100039 monitoring during irradiation, place at 3m from neutron2318400100040 source. 2318400100041 The absolute efficiency of the detectors was obtained 2318400100042 using a calibrated 152Eu source placed at the same 2318400100043 distance as the samples. Calibrated monoenergetic 2318400100044 sources 54Mn, 60Co, 56Co, 137Cs, 22Na were used at 2318400100045 distances of 28 and 7 cm from the detector front to 2318400100046 correct the 152Eu efficiency for summing effects, which2318400100047 did not exceed 6%. 2318400100048 MONITOR (13-AL-27(N,A)11-NA-24,,SIG) 2318400100049 (41-NB-93(N,2N)41-NB-92-M,,SIG) 2318400100050 (79-AU-197(N,2N)79-AU-196,,SIG) 2318400100051 (79-AU-197(N,G)79-AU-198,,SIG) 2318400100052 To deduce neutron flux. 2318400100053 DECAY-MON (11-NA-24,14.96HR,DG,1368.6,1.00) 2318400100054 (41-NB-92-M,10.15D,DG,934.,0.99) 2318400100055 (79-AU-196,6.2D,DG,355.7,0.87) 2318400100056 (79-AU-198,2.69D,DG,411.,0.986) 2318400100057 CORRECTION For self-absorption and counting geometry of the 2318400100058 emitted gamma rays in the activated sample using the 2318400100059 code MCNP4C, were found to be 35% in the case of 2318400100060 Egamma=123 keV and 5% for Egamma=343 keV. 2318400100061 For coincidence summing effects. 2318400100062 For the decay of the product nuclide during the 2318400100063 irradiation and the counting collection time. 2318400100064 ADD-RES (COMP) Data are compared with EMPIRE-II and TALYS 2318400100065 calculations. 2318400100066 ERR-ANALYS Considered errors : 2318400100067 - in the determination of the efficiency of the HPGe 2318400100068 detector, 2318400100069 - statistical errors of the photopeak areas, 2318400100070 - errors in the emission probabilities and the 2318400100071 determination of the target masses, 2318400100072 - the errors in the reference reactions cross 2318400100073 sections. 2318400100074 -The error of the neutron-beam energy was determined by2318400100075 considering the kinematics of the d-d reaction, the 2318400100076 actual size and material of the cell window, the 2318400100077 pressure of the gas cell, the distance of the samples 2318400100078 from the middle of the cell. It was found to be less 2318400100079 than 0.1MeV. 2318400100080 HISTORY (20121016C) M.M. 2318400100081 ENDBIB 79 0 2318400100082 NOCOMMON 0 0 2318400100083 ENDSUBENT 82 0 2318400199999 SUBENT 23184002 20121016 22332318400200001 BIB 5 21 2318400200002 REACTION (72-HF-174(N,2N)72-HF-173,,SIG) 2318400200003 DECAY-DATA (72-HF-173,23.6HR,DG,123.67,0.83) 2318400200004 SAMPLE Natural Hf-O(2) pellets of 1.3 cm diameter, masses 2318400200005 from 0.667 g to 0.953 g, produced by compressing a 2318400200006 mixture of high 99.9% purity powder Hf-O(2) and C in 2318400200007 concentrations 88% and 12%, respectively. 2318400200008 Thin metallic targets of high-purity Hf with masses 2318400200009 about 0.95 g of 1.3 cm diameter were also used for 2318400200010 some of the measurements. 2318400200011 Reference foils of high-purity Al, Nb, Au (of the same 2318400200012 diameter as the Hf target) were placed in the front and2318400200013 the back of the target. 2318400200014 Samples were stacked together in an aluminum holder at2318400200015 0 deg with respect to the beam direction, at distances 2318400200016 from 7 to 12 cm from the end of the deuterium gas cell.2318400200017 After the irradiation, the samples were placed 7cm from2318400200018 the window of two HPGe detectors. 2318400200019 ERR-ANALYS (DATA-ERR) Not specified. 2318400200020 STATUS (TABLE) Table II of J,PR/C,86,034602,2012 . 2318400200021 (COREL,22969004) Other measurement for EN 9.8, 11.1, 2318400200022 11.5 MeV. 2318400200023 ENDBIB 21 0 2318400200024 NOCOMMON 0 0 2318400200025 DATA 3 2 2318400200026 EN DATA ERR-T 2318400200027 MEV MB MB 2318400200028 10.5 807. 104. 2318400200029 11.0 1622. 363. 2318400200030 ENDDATA 4 0 2318400200031 ENDSUBENT 30 0 2318400299999 SUBENT 23184003 20121016 22332318400300001 BIB 6 33 2318400300002 REACTION 1(72-HF-176(N,2N)72-HF-175,,SIG) 2318400300003 Corrected data 2318400300004 2((72-HF-176(N,2N)72-HF-175,,SIG)+ 2318400300005 (72-HF-174(N,G)72-HF-175,,SIG,,RAB)) 2318400300006 Uncorrected data , include contribution of 2318400300007 174Hf(n,gamma)175Hf reaction . 2318400300008 DECAY-DATA (72-HF-175,70.D,DG,343.4,0.84) 2318400300009 SAMPLE Natural Hf-O(2) pellets of 1.3 cm diameter, masses 2318400300010 from 0.667 g to 0.953 g, produced by compressing a 2318400300011 mixture of high 99.9% purity powder Hf-O(2) and C in 2318400300012 concentrations 88% and 12%, respectively. 2318400300013 Thin metallic targets of high-purity Hf with masses 2318400300014 about 0.95 g of 1.3 cm diameter were also used for 2318400300015 some of the measurements. 2318400300016 Reference foils of high-purity Al, Nb, Au (of the same 2318400300017 diameter as the Hf target) were placed in the front and2318400300018 the back of the target. 2318400300019 Samples were stacked together in an aluminum holder at2318400300020 0 deg with respect to the beam direction, at distances 2318400300021 from 7 to 12 cm from the end of the deuterium gas cell.2318400300022 After the irradiation, the samples were placed 7cm from2318400300023 the window of two HPGe detectors. 2318400300024 CORRECTION1Technique has been developed using the (n,g) and (n,2n)2318400300025 reactions on 197Au to investigate the influence of the 2318400300026 174Hf(n,g)175Hf reaction on the production of 175Hf. 2318400300027 ERR-ANALYS (DATA-ERR) Not specified. 2318400300028 (ERR-1,,8.) Uncertainty of up to 8% (for higher energy 2318400300029 to account for the inherent assumptions of the 2318400300030 correction method. 2318400300031 STATUS (TABLE) Table III of J,PR/C,86,034602,2012 . 2318400300032 (COREL,22969007) In 22969.007 - c-s not corrected for 2318400300033 contribution of parasitic neutrons; 2318400300034 previous measurement. 2318400300035 ENDBIB 33 0 2318400300036 NOCOMMON 0 0 2318400300037 DATA 5 5 2318400300038 EN DATA 1DATA-ERR 1DATA 2DATA-ERR 2 2318400300039 MEV MB MB MB MB 2318400300040 8.8 418. 41. 474. 41. 2318400300041 9.0 730. 30. 760. 30. 2318400300042 10.0 904. 101. 1002. 93. 2318400300043 10.5 1586. 203. 1921. 164. 2318400300044 11.0 1661. 276. 2415. 244. 2318400300045 ENDDATA 7 0 2318400300046 ENDSUBENT 45 0 2318400399999 ENDENTRY 3 0 2318499999999