ENTRY 23036 20121021 22332303600000001 SUBENT 23036001 20121021 22332303600100001 BIB 13 98 2303600100002 TITLE .Measurement of the D(n,2n)p reaction cross section 2303600100003 up to 30 MeV 2303600100004 AUTHOR (J.-M.Laborie, X.Ledoux, C.Varignon, R.Lazauskas, 2303600100005 B.Morillon, G.Belier, D.Dore, N.Arnal) 2303600100006 INSTITUTE (2FR BRC) CEA/DAM, Ile de France - DPTA/SPN, 2303600100007 Bruyere-le-Chatel, France. J.-M.Laborie, X.Ledoux, 2303600100008 C.Varignon, R.Lazauskas, B.Morillon, G.Belier, 2303600100009 N.Arnal 2303600100010 (2FR SAC) CEA/Saclay DAPNIA/SPhN, Gif-sur-Yvette, 2303600100011 France. D.Dore 2303600100012 REFERENCE (J,EPJ/A,48,87,2012) Data in Tables. 2303600100013 #doi:10.1140/epja/i2012-12087-4 2303600100014 (C,2007NICE,1,437,200704) ND2007 report #313. 2303600100015 #doi:10.1051/ndata:07313 2303600100016 Graph of only preliminary data. 2303600100017 Abstracts, analogous to 2303600100018 main reference 2303600100019 REL-REF (I,,C.Varignon+,J,NIM/B,248,329,2006) Description 2303600100020 of 7 MV tandem accelerator 2303600100021 FACILITY (VDGT,2FR BRC) Tandem 7 MV accelerator, beam nominal 2303600100022 frequency 2.5 MHz 2303600100023 INC-SOURCE (D-D,P-T) 5 - 10 MeV neutrons 2303600100024 (D-T) 20 - 25 MeV neutrons 2303600100025 INC-SPECT .Monoenergetic neutrons corresponding to the above 2303600100026 given source reactions and broad low-energy tail. 2303600100027 TOF technique was employed to select the neutrons 2303600100028 corresponding to the monoenergetic peak. 2303600100029 DETECTOR (SCIN) A 4pi neutron detector called CARMEN is a large 2303600100030 spherical neutron detector, constituted of two 2303600100031 independent vertical hemispheres, 60cm outer-radius, 2303600100032 15cm inner radius, each one filled with less than 2303600100033 0.5 m3 of gadolinium-loaded scintillating liquid 2303600100034 (BC521) used for counting the two outgoing neutrons. 2303600100035 Efficiency measured by 252-Cf trigger is 80% 2303600100036 diminishing to 75% at 20-25 MeV neutron energy. 2303600100037 (SOLST) 12.5 cm diameter, 5cm thick NE213 scintillation2303600100038 detectors were used to monitor neutron beam:2 2303600100039 one - to measure neutron flux, other - measure the 2303600100040 energy of incident neutrons. 2303600100041 NE213 neutron flux monitor was calibrated at seven 2303600100042 neutron energies between 5.8 and 22MeV at the German 2303600100043 Lab.of Neutron Metrology (PTB).Efficiency was measured 2303600100044 for the same low-energy threshold as the one used in 2303600100045 the present experiment, with an accuracy obtained 2303600100046 reaches 2% at energies up to 12MeV and 4% beyond this 2303600100047 point. 2303600100048 METHOD (TOF) Used for separation of sharp neutron beam from 2303600100049 the broad background . 2303600100050 Flight path 13m from the neutron production target. 2303600100051 SAMPLE .Active deuteron target as 12.5cm diameter x 5cm thick 2303600100052 (2x2inch) aluminum cell containing the 103 cm3 2303600100053 scintillating liquid. Detector placed in the reaction 2303600100054 chamber of CARMEN . 2303600100055 To take into account the (n,2n) reactions on elements 2303600100056 B, C, Si, O, Al ( present inside or in the vicinity of 2303600100057 the active target volume), dedicated runs were done 2303600100058 with a C6H6 hydrogenated target, with the same 2303600100059 dimensions and scintillating properties as the 2303600100060 deuterated one. 2303600100061 C6D6 target: 4.06E+22 H-2 atoms per cm**3, 3.55E+20 2303600100062 H-1 atoms per cm**3, 4.10E+22 C atoms per cm**3. 2303600100063 C6H6 target: 4.0955E+22 H-1 atoms per cm**3, 4.10E+22 2303600100064 C atoms per cm**3. 2303600100065 CORRECTION The Monte Carlo simulation code SIM was used to 2303600100066 calculate correction factors taking into account the 2303600100067 energy resolution, the spatial neutron beam profile, 2303600100068 detailed description of the target, every possible 2303600100069 reaction, the energy-angle correlations between the 2303600100070 two neutrons and the proton. 2303600100071 Contribution of C6H6 was subtracted. 2303600100072 Detector efficiency was checked by Cf-252 sample and 2303600100073 MCNP code calculations. 2303600100074 For neutron absorption in the target - transmission 2303600100075 was measured by measuring the flux with and without 2303600100076 the target. It varies between 50% to 70%, depending on 2303600100077 the incident energy. 2303600100078 The resulting correction factor from: 2303600100079 - correction for the finite-geometry effects of the 2303600100080 target; 2303600100081 - correction for the 2H(n,2n)p reaction losses due to 2303600100082 the proton recoil threshold; 2303600100083 - correction for the extra 2H(n,2n) reactions occurring2303600100084 in the expansion chamber and detected in the active 2303600100085 volume. 2303600100086 Total correction was applied to the measured finite- 2303600100087 geometry cross-section data and amounts to 4.1-4.3% for2303600100088 20-25MeV incident neutron energies, varies from 12.6% 2303600100089 to 16.2% for 5-8 MeV incident neutron energies . 2303600100090 HISTORY (20081012C) SM 2303600100091 (20101106A) SD: doi for ref. 2007NICE,1,437,2007 2303600100092 corrected. Author's name corrected (D.Doree => D.Dore) 2303600100093 Ref. on NIM/B,248 moved to REL-REF 2303600100094 In Subent 002 ERR-SYS renamed as ERR-T according to 2303600100095 description in the article. Precision of the data are 2303600100096 corrected. 2303600100097 (20121021A) M.M. Ref. J,EPJ/A,48,87,2012 was added. 2303600100098 Digitized data were replaced by data of Tables. 2303600100099 Subent 003 was added. BIB information was added. 2303600100100 ENDBIB 98 0 2303600100101 NOCOMMON 0 0 2303600100102 ENDSUBENT 101 0 2303600199999 SUBENT 23036002 20121021 22332303600200001 BIB 6 32 2303600200002 REACTION (1-H-2(N,2N)1-H-1,,SIG) 2303600200003 ERR-ANALYS (ERR-T) Total uncertainty 2303600200004 (ERR-S,0.9,4.5) Statistical uncertainty 2303600200005 Uncertainties of normalization: 2303600200006 (ERR-1) Uncertainty due to monoenergetic peak area on 2303600200007 the tof spectrum. 2303600200008 (ERR-2) Uncertainty due to NE213 detection efficiency. 2303600200009 (ERR-3,3.,5.) Uncertainty due to target transmission. 2303600200010 (ERR-4,4.2,5.8) Uncertainty due to total incident 2303600200011 neutron fluence. 2303600200012 Uncertainties of reaction rate: 2303600200013 (ERR-5,4.9,6.7) Uncertainty due to experimental 2303600200014 reaction rate for one neutron. 2303600200015 (ERR-6,0.5,1.8) Uncertainty due to CARMEN efficiency 2303600200016 for 252Cf neutrons. 2303600200017 (ERR-7,5.4,7.2) Uncertainty due to reaction rate 2303600200018 for given fluence. 2303600200019 All the points are considered except for the one at 2303600200020 6.8MeV for which the uncertainty is much larger (13.5%)2303600200021 because of low statistics. 2303600200022 INC-SPECT Energy resolution is less 2.% . 2303600200023 STATUS (TABLE) Table 5 of J,EPJ/A,48,87,2012. 2303600200024 Fig.4 of C,2007NICE,1,437,2007 - prelim.data. 2303600200025 COMMENT Of authors. Two values measured at 6.8MeV, for two 2303600200026 distinct campaigns, agree well within the 68% C.L. 2303600200027 uncertainties, indicating a good repeatability of the 2303600200028 measurements. 2303600200029 HISTORY (20110206A) SD: ERR-SYS renamed as ERR-T according to 2303600200030 description in the article. Precision of the data are 2303600200031 corrected. 2303600200032 (20121021) Digitized data were replaced by data of 2303600200033 table. ERR-ANALYS was updated. 2303600200034 ENDBIB 32 0 2303600200035 COMMON 2 3 2303600200036 ERR-1 ERR-2 2303600200037 PER-CENT PER-CENT 2303600200038 2. 2. 2303600200039 ENDCOMMON 3 0 2303600200040 DATA 4 7 2303600200041 EN EN-ERR DATA ERR-T 2303600200042 MEV MEV MB MB 2303600200043 5.54 0.08 57.6 3.3 2303600200044 5.81 0.09 60.5 3.4 2303600200045 6.34 0.10 74.9 4.2 2303600200046 6.83 0.10 74.6 4.2 2303600200047 6.83 0.15 82.6 11.2 2303600200048 7.23 0.15 85.5 6.2 2303600200049 7.75 0.15 98.6 7.2 2303600200050 ENDDATA 9 0 2303600200051 ENDSUBENT 50 0 2303600299999 SUBENT 23036003 20121021 22332303600300001 BIB 5 21 2303600300002 REACTION (1-H-2(N,2N)1-H-1,,SIG) 2303600300003 ERR-ANALYS (ERR-T) Total uncertainty 2303600300004 (ERR-S,1.1,4.8) Statistical uncertainty 2303600300005 Uncertainties of normalization: 2303600300006 (ERR-1) Uncertainty due to monoenergetic peak area on 2303600300007 the tof spectrum. 2303600300008 (ERR-2) Uncertainty due to NE213 detection efficiency. 2303600300009 (ERR-3,3.,5.) Uncertainty due to target transmission. 2303600300010 (ERR-4,5.5,6.7) Uncertainty due to total incident 2303600300011 neutron fluence. 2303600300012 Uncertainties of reaction rate: 2303600300013 (ERR-5,6.4,9.6) Uncertainty due to experimental 2303600300014 reaction rate for one neutron, measured with CARMEN. 2303600300015 (ERR-6,0.5,1.8) Uncertainty due to CARMEN efficiency 2303600300016 for 252Cf neutrons. 2303600300017 (ERR-7,7.5,9.7) Uncertainty due to reaction rate 2303600300018 for given fluence. 2303600300019 INC-SPECT Energy resolution is less 2.% . 2303600300020 STATUS (TABLE) Table 6 of J,EPJ/A,48,87,2012. 2303600300021 Fig.4 of C,2007NICE,1,437,2007 - prelim.data. 2303600300022 HISTORY (20121021C) M.M. Subent was added. 2303600300023 ENDBIB 21 0 2303600300024 COMMON 2 3 2303600300025 ERR-1 ERR-2 2303600300026 PER-CENT PER-CENT 2303600300027 2. 4. 2303600300028 ENDCOMMON 3 0 2303600300029 DATA 4 11 2303600300030 EN EN-ERR DATA ERR-T 2303600300031 MEV MEV MB MB 2303600300032 20.2 0.4 172.4 14.1 2303600300033 21.2 0.4 153.7 11.8 2303600300034 21.6 0.4 128.9 10.9 2303600300035 21.8 0.3 142.6 11.0 2303600300036 21.8 0.3 136.3 10.1 2303600300037 21.8 0.4 131.8 12.1 2303600300038 22.4 0.3 134.1 10.9 2303600300039 23.0 0.3 132.1 11.5 2303600300040 23.5 0.3 154.4 12.2 2303600300041 24.1 0.3 141.6 13.8 2303600300042 24.7 0.3 141.8 11.0 2303600300043 ENDDATA 13 0 2303600300044 ENDSUBENT 43 0 2303600399999 ENDENTRY 3 0 2303699999999