SUBENT        21643001     810415   20050616   20050926       0000
BIB                 16         44
INSTITUTE  (2UK LON) UNIV OF LONDON REACTOR CENTRE, IMPERIAL
            COLLEGE.
REFERENCE  (S,INDC(NDS)-107,183,7908) PROCEEDINGS OF THE
            CONSULTANTS MEETING ON DELAYED NEUTRON PROPERTIES,
            VIENNA, 26-30 MARCH 1979.
AUTHOR     (S.SYNETOS,J.G.WILLIAMS)
TITLE      -DELAYED NEUTRON YIELD AND DECAY CONSTANTS FOR THERMAL
            NEUTRON INDUCED FISSION OF U-235 -.
FACILITY   (REAC ) THERMAL RESEARCH REACTOR, UNIV OF LONDON.
INC-SOURCE (THCOL) THERMAL COLUMN.
INC-SPECT  THERMAL MAXWELLIAN NEUTRON SPECTRUM
SAMPLE     .SAMPLES WERE METAL FOILS OF 7.5 MM DIAMETER, 35 MG
            IN WEIGHT, ENRICHED TO 95.54 PERCENT U-235.
METHOD     .SAMPLES TRANSFERRED PNEUMATICALLY TO AND FROM THE
            IRRADIATION POSITION WHERE A CONSTANT THERMAL FLUX
            WAS MAINTIANED. AFTER EACH IRRADIATION THE DELAYED
            NEUTRON EMISSION RATE WAS MEASURED IN A DETECTOR
            CONSISTING OF A WATER BATH CONTAINING BF3 CONTERS.
DETECTOR   (SCIN ) WATER BATH CONTAINING BF3 COUNTERS IN
            CYLINDRICAL ALUMINIUM TUBES OF O.D. 26 MM. ACTIVE
            LENGTH 310MM. FILLED WITH 96 PERCENT B-10.
            THE EFFICIENCY WAS CALIBRATED WITH A STANDARD AM/LI
            SOURCE FROM N.P.L. WHICH WAS ITSELF CALIBRATED TO
            0.5 PERCENT USING A MANGANESE SULPHATE BATH.
ANALYSIS   .MEASURED NEUTRON DECAY CURVE WAS FITTED TO THE SUM
            OF FIVE EXPONENTIAL DECAYING GROUPS BY A LEAST SQUARE
            METHOD. NO SIXTH GROUP WAS OBSERVED BECAUSE OF THE
            TRANSFER TIME OF 380 MS BEFORE COUNTING.
MONITOR    (92-U-235(N,F)57-LA-140,CUM,FY,,MXW) THE NUMBER OF
            IN THE U-235 SOURCE WAS MONITORED BY MEASURING THE
            ACTIVITY OF LA-140 RELATIVE TO A CALIBRATION FOIL
            IN AN ABSOLUTE IONISATION CHAMBER. NO VALUE GIVEN.
CORRECTION .CORRECTIONS MADE FOR VOLUME OF AM/LI CALIBRATION
            SOURCE, NEUTRON SELF ABSORPTION IN CALIBRATION
            SOURCE (ANISN CALC.), ANISOTROPY OF NEUTRON EMISSION,
            ENERGY SPECTRUM EFFECTS OF AM/LI RELATIVE TO THAT
            OF DELAYED NEUTRONS (TABLE 1.)
            THE TOTAL YIELD WAS CORRECTED FOR THE ABSENCE OF
            THE SIXTH GROUP.
ERR-ANALYS .QUOTED ERROR INCLUDES STATISTICAL UNCERTAINTY PLUS
            ERRORS ON CORRECTIONS AND IN DETECTOR EFFICIENCY.
STATUS     .TEXT AND TABLES IN 1NDC(NDS)-107.
HISTORY    (800825C)
           (800829E)
ENDBIB              44
COMMON               1          3
EN-DUMMY
EV
 2.5300E-02
ENDCOMMON            3
ENDSUBENT           51
SUBENT        21643002     800829   20050616   20050926       0000
BIB                  5         14
REACTION   (92-U-235(N,F),DL/PAR,NU,,MXW/REL)
HALF-LIFE  .THE HALF-LIFE FITTED TO EACH DELAYED GROUP IS
            GIVEN IN THE TABLE, COMPARISON IS MADE WITH THE
            VALUES OF KEEPIN ET AL. IN TABLE 3.
ANALYSIS   .YIELDS ARE NORMALISED TO A SUM OF UNITY.
STATUS     .TABLE 3.
ERR-ANALYS .THERE ARE STRONG CORRELATIONS BETWEEN THE YIELDS
            FOR THE FIVE MEASURED GROUPS.
             GROUP.          CORRELATION MATRIX FOR DL/YLDS.
               1.             1.   0.63 -0.42  0.27 -0.15
               2.             0.63 1.   -0.54  0.32 -0.20
               3.            -0.42 -0.54 1.   -0.62 -0.38
               4.             0.27  0.32 -0.62 1.   -0.38
               5.            -0.15 -0.20 -0.38 -0.38 1.
ENDBIB              14
NOCOMMON             0          0
DATA                 4          5
HL         HL-ERR     DATA       DATA-ERR
SEC        SEC        ARB-UNITS  ARB-UNITS
 7.7000E-01 1.0000E-01 1.8700E-01 1.7000E-02
 2.7200E+00 2.2000E-01 4.0300E-01 1.7000E-02
 7.0000E+00 6.3000E-01 1.4800E-01 2.3000E-02
 2.2350E+01 2.5000E-01 2.2700E-01 9.0000E-03
 5.6530E+01 5.5000E-01 3.5000E-02 2.0000E-03
ENDDATA              7
ENDSUBENT           26