ENTRY 14384 20140403 13991438400000001 SUBENT 14384001 20140403 13991438400100001 BIB 10 39 1438400100002 TITLE A new neutron counter for fission research 1438400100003 AUTHOR (B.Laurent,T.Granier,G.Belier,A.Chatillon,J.-F.Martin, 1438400100004 J.Taieb,F.-J.Hambsch,F.Tovesson,A.B.Laptev,R.C.Haight, 1438400100005 R.O.Nelson,J.M.O'Donnell) 1438400100006 INSTITUTE (2FR BRC,2ZZZGEL,1USALAS) 1438400100007 REFERENCE (J,NIM/A,745,99,2014) 1438400100008 FACILITY (LINAC,1USALAS) Experiment performed at the 800 MeV 1438400100009 proton linac of the Lujan Neutron Scattering Center 1438400100010 at LANSCE 1438400100011 SAMPLE Thin deposit containing 1mg of 238U. Sample was 1438400100012 placed inside of the ionization chamber. 1438400100013 DETECTOR (HE3SP) Neutron detector consists of 30 cylindrical 3He1438400100014 proportional counters arranged in two concentric 1438400100015 rings within a high-density polyethylene matrix. 1438400100016 Twelve 3He tubes with a diameter of 2.54cm,an active 1438400100017 length of 30 cm and 10 bar of gas pressure, and 1438400100018 eighteen tubes with a diameter of 2.54cm, an active 1438400100019 length of 45cm and 4 bar of gas pressure were used in 1438400100020 this setup. The inner detector ring corresponds to a 1438400100021 13.5 cm radius and is composed of twelve high 1438400100022 pressure and six low pressure tubes.The twelve 1438400100023 remaining lower pressure tubes constitute the second 1438400100024 ring which has a 19 cm radius. The polyethylene 1438400100025 matrix is a rectangular block with a square section 1438400100026 of 50 cm side and 75 cm long 1438400100027 (IOCH) Both fission fragments were detected by a 1438400100028 double Frisch- gridded ionization chamber, with 1438400100029 contained 238U sample 1438400100030 METHOD (TOF) Energy of primary neutrons was determined by time1438400100031 of flight. Neutron flight path was about 10 m. The 1438400100032 proton beam was delivered in subnanosecond micropulses 1438400100033 emitted every 1.8 mu-s within macropulses of 625 mu-s 1438400100034 long at a 40Hz repetition rate 1438400100035 INC-SOURCE (SPALL) Spallation neutrons were produced by a pulsed 1438400100036 800 MeV proton beam with a repetition rate of 20 Hz 1438400100037 impinging on a pair of tungsten targets. Neutrons are 1438400100038 reflected by the moderator and travel down a 20.2-m 1438400100039 flight path to the target location. 1438400100040 HISTORY (20140403C) Compiled by S.H. 1438400100041 ENDBIB 39 0 1438400100042 NOCOMMON 0 0 1438400100043 ENDSUBENT 42 0 1438400199999 SUBENT 14384002 20140403 13991438400200001 BIB 4 7 1438400200002 REACTION (92-U-238(N,F),PR,NU) 1438400200003 STATUS (TABLE) Data presented in fig. 13 of the reference 1438400200004 sent by author (B.L.) 1438400200005 ERR-ANALYS (ERR-S) Statistical uncertainty 1438400200006 ANALYSIS Prompt fission neutron multiplicity is given by the 1438400200007 integral of the background subtracted spectrum 1438400200008 divided by the detection efficiency. 1438400200009 ENDBIB 7 0 1438400200010 NOCOMMON 0 0 1438400200011 DATA 3 21 1438400200012 EN DATA ERR-S 1438400200013 MEV PRT/FIS PRT/FIS 1438400200014 1.39057 2.50296 0.355338 1438400200015 1.58525 2.89963 0.249436 1438400200016 1.80719 2.47254 0.208494 1438400200017 2.06019 2.77328 0.196131 1438400200018 2.34862 2.76306 0.185854 1438400200019 2.67743 2.64286 0.185945 1438400200020 3.05227 2.61352 0.181496 1438400200021 3.47958 2.33066 0.186384 1438400200022 3.96673 2.78304 0.171980 1438400200023 4.52207 2.92825 0.167301 1438400200024 5.15516 2.87890 0.159823 1438400200025 5.87688 3.19902 0.154175 1438400200026 6.69964 3.29485 0.128396 1438400200027 7.63759 3.52655 0.134278 1438400200028 8.70686 3.68242 0.136136 1438400200029 9.92582 3.86793 0.145246 1438400200030 11.3154 3.81355 0.155891 1438400200031 12.8996 4.39874 0.160402 1438400200032 14.7055 4.69169 0.158944 1438400200033 16.7643 4.87619 0.154534 1438400200034 19.1113 5.20817 0.153385 1438400200035 ENDDATA 23 0 1438400200036 ENDSUBENT 35 0 1438400299999 ENDENTRY 2 0 1438499999999