JAERI-Data Code 96-005 JAKKI - Da t n/Cada—CKf-005 EXPERIMENTS ON IRON SHIELD TRANSMISSION OF QUASI-MONOENERGETIC NEUTRONS GENERATED BY 43-AND 68-MeV PROTONS VIA THE 7 Li(p,n) REACTION March 1996 Hiroshi XAKASHIMA, Noriaki XAKAO' 1 , Shun-ichi TAXAKA TakoMhi NAKA3IUKA*' Kazuo SHIN"' Susumu TANAKA Shin-Ichiro MEKJO, Yoshihiro XAKANE, Hiroshi TAKADA Yukio SAKAMOTO and Mumoru IIABA' 1 Japan Atomic Energy Research Institute VOL 27HS17
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JAERI-Data Code96-005 JAKKI - Da t n/Cada—CKf-005
EXPERIMENTS ON IRON SHIELD TRANSMISSION OFQUASI-MONOENERGETIC NEUTRONS GENERATED
BY 43-AND 68-MeV PROTONS VIA THE 7Li(p,n) REACTION
This research report is the result of the joint study with University of Tokyo,Tohoku University and Kyoto University.• Office of Planning•• Advanced Radiation Technology Center, Takasaki Radiation Chemistry Research
Establishment•l University of Tokyo, Institute for Nuclear Study** Tohoku University, Cyclotron and Radioisotope Center•3 Kyoto University•' Tohoku University
.JAKHI-lJHlu/Codo 1)6-006
Q * B W J Glf ftrfr HOT » , r { W
- i s * * * -JdiW s i r
( 'J:
iP TLD.
: f 319-11 ^«»II5IiIWJK»He3!rfiffl 2 - 4
JAKW-JWCodo 0«—005
Contents
1. I n t r o d u c t i o n ••••• ••••" - • ••"" 1
2. Experiment • • •• 3
2.1 TIARA Facility and Experimental Sot Up 3
2.2 Neutron Sources 3
2.3 Detectors and Data Analysos for Shielding Experiment 4
2.3.1 BC501A Liquid Scintillation Counter \
2.3.2 Bonnor Ball Counter • •••••• •"• 5
2.3.3 Fission Counters •••• 5
2.3.4 Thermolumine3cent Dosimeter(TLD) 0
2.3.5 Solid Stato Nuclear Track Doteotor(SSNTD) 6
3. Results •"- - 7
3.1 Neutron Spectra in tha Energy Region above a fe« MeV Measured by
the BC501A Detector 7
3.2 Neutron Reaction Rates and Spectra in the Energy Region Up to a
Few MeV Measured by the Bonner Ball Counter "7
3.3 Neutron Reaction Rates Measured by Fission Counters, TLDs and SSNTD -••• 7
3.4 Neutron Dose Equivalent 8
4. Summary • • 9
Acknowledgements 9
References 10
JAKUI-Dntn/CVido 9B-005
2. US tt • • • • 3
2. 1 TIARAOWKitfettflBffl 32. 2 'f'tftfjp. 32. 3 « J M l « $ f c * 0 A W ? £ 4
to a R4143 photomultiplicr (Hamamatsu Photonics. Co. Ltd.). The block diagram of the
measuring electronic circuit for the shielding experiment is also shown in Fig.3. The rise-time
pulses which distinguished between neutron-cvent and photon-cvent were supplicJ by the
risc-rimc-to-hcight converter (OHYO KOKEN KOGYO Co., Ltd.). In the shielding
experiment, the two pulses of pulsc-hcight and rise-time were recorded in cvcnt-by-cvcnt
mode. These data were taken by the ND9900 MPA 8/16 (CAMBERRA Co. Ltd.) and the VAX
STATION 3100 (DEC Co. Ltd.), then recorded in a hard disk.
• JAKIU- i)/it/i/C(i(l(- 00--OOfi
Tlic cvent-by-cvent data measured with 13C501A were converted to two dimensional
distribution of pulse-height and rise-time, mid the pulse-height distributions induced by
neutrons were selected by eliminating the y-ray pulses, Then they were converted into the
neulron energy speclra using the FERDOU unfolding code10 and the measured response matrix".
The energy calibration of the light output pulses was performed using the Compton edge of
4.43-McV y-rays from a wlAm-Bc source and the recoiled proton edge of 40- or 65-McV
monocnergetic neutron peak of 43- or fih-MeV p-Li reaction fitted to the calibration values
from Rcf.[K], and using the zero point with a Research Pulscr. The dead time correction of the
data taking system was done from the difference of the number counted in the sealer and the
number of events which were recorded in the hard disk. Finally the absolute values of the
transmitted spectra are presented as the flux per proton beam charge (jiQ which can be estimated
from the flucnce monitor counts.
2.3.2 Bonner ball counter
Multi-moderator spectrometer, Bonncr ball, with four spherical polyethylene moderators
of 1.5, 3.0, 5.0 and 9.0 cm thicknesses and without moderator was also used for the shielding
experiment. The thermal neutron detector inserted in the center of the moderator is a
5.0H-cm-diam. spherical proportional counter, made by LND Inc., filled with 10 atm (at 22 )3Hc gas. The pulse height spectra for five different moderators of the Bonncr ball counter were
recorded.
The pulse height data measured with the Bonncr ball counter were summed up to get
counts above the y-ray discrimination level. These five counts measured for five moderators
were unfolded with the SAND-2 code" and the response matrix given by Uwamino ct al12. The
response matrix is shown in Fig. 5 and given in Table 5. Initial guess spectra used in unfolding
were obtained from the MORSE13 calculations with the H1LO86 group cross section set14 at each
measured position. We then obtained the spectra of neutrons in the energy range from K)"4 cV
to the peak energy.
2.3.3 Fission counters
^"U and a2Th fission counters (Ccntronic FC480/10U0) with a 10.1-cm-longx 3.81-
cm-diam. active volume were used for measuring neutron reaction rates behind the iron shield.
- 5 -
.IAKM
tetenejes wcrc calibrated by the mCispontaneous fission neutron source of
Facility «f Radiation StunUtifd (FK8)15 of JAKRI, 'Hie facility l« the .wewml hiundurd field of
neutron, The neutron source ImU an intensity of 1.218 x \(f n/*cc with the uncertainty of ±3%.
The measured efffdenefefr are M>5 * I01 ami 1>M> n H? b&m/em*/&MM» (±4 uml 3,4%)f
respectively. The rtsslort cross sections of m\J tintl M2Th have been evaluated up to 20 McV in
JENDL~y\ tneusuted by Liwnvski el »),'•'* in Ihc energy region between 20 and 400 McV and
calculated using the IIIiTC code above 400 McV, The cross sections arc shown in Fig. (»and
the group cross section data are given in Table (u
2.3.4 Thcrmolumincsccnt dosimeter (TLfl)
Neutron reaction rates were measured on the axis of the beam in the iron shield using
"iWimil M<JJ TU>¥(JJWMMW V.th Ud,) of ] s 1 x 6 nmi\ Thez/noJumluesccncc wiwfc«tl t)ut
by a TLD reader (f ianhaw 2(KK)), and converted to the absolute dose in TLDs using a calibration
factor determined with'"Co y-ray.s of I KS within the uncertainty less than 3 %. The neutron
energy responses were calculated by a code developed by Ilashikura ct al. which was based on
a KliUMA calculation". The calculated neutron energy responses arc shown in Fig. 7 and
tabulated in Table 7.
2.3.5 Solid state nuclear track detector (SSNTD)
The neutron reaction rales in ihc shield were also measured using a solid state nuclear
track detector: Types TS~luN resin manufactured by Fttkuvi Chemical Industry Co. Ltd. from
ti monomer (TS-1 OS) made by Tokuyama Soda Ltd. The composition of the detector is the same
m thai of CK-39 (Allyl tfiglyeo! cyiboiiuic). The detector Ls u iccujngulux solid of 10 x 5 x t
mm* attached with a polyethylene radiator of 1 mm thick. After Ihc exposed detectors were
etched chemically, the etch pits on the detectors were counted through the optical microscope
of 400 limc» magnifications. The neutron response was calculated by a Monte Carlo code system:
SSNRHS31. bstscd on the SCINFUL codcJl. The calculated neutron response is shown in Fig.
K and given in Table K.
,\A\''M\ -\)nln/CiHk< JKi-OOf)
3. KliSULTS
3.1 Neutron spectra in the energy region above n few MeV measured by the BC501A detector
Neutron spectra in the energy region above a few McV were measured just behind the
iron shield on the beam axis and at the off-center positions of 20 and 40 cm from the beam axis
as tabulated in Table 1 using (he BC501A detector. Figure 9 shows the measured neutron energy
spectra behind various thickness of iron up to 100 cm on the beam axis for 43-MeV p-Li
neutrons. The errors of the measurement in the figure include only errors of spectrum unfolding
and counting statistics in the measurement, neglecting that the source neutron flux has errors of
lJRT(3-5%), conversion factor of flucncc monitor to total charges of proton beam (3%), neutron
penetration factor through objects on the beam line (3%) and the flucnu monitor counting
statistics (less than 1%). The measured ncutruij spectra at the positions of 20 and 40 cm from
the beam uxJ.v behind ()-, 11)-, 20- and 40-cm thick .shields arc shown )n Figs, 10 through 13
for 43-McV p-Li neutrons, respectively, The measured neutron spectra for 6K-McV p-Li
neutrons arc also shown in Figs, 14 through 17 behind the iron shield of thickness up to 130 cm
on the beam axis and at the positions of 20 and 40 cm from the beam axis. The measured
neutron spectra arc also tabulated in Tables 9 through 20.
3.2 Neutron reaction rates and spectra in the energy region up to a few McV measured by the
Oonncr ball counter
Neutron reaction rates behind the iron shields up to 100 cm thick on the beam axis were
measured using the Bonncrball counter with four spherical polyethylene moderators of 1.5,3.0,
5.0 and 9.0 cm thicknesses and without moderator as given in Tables 21 and 22. Neutron spectra
obtained from the reaction rates using the SAND-2 unfolding code and the calculated response
matrix arc shown in Figs. 18 and 19 for 43- and 68-McV p-Li neutrons, and the numerical data
arc given in Tables 23 ad 24. The experimental errors of the Bonncr ball counter could not be
obtained since the SAND-2 unfolding code can not give them.
3.3 Neutron reaction rates measured by fission counters, TLDs and SSNTD
Fission reaction rates were measured behind the shields of various thicknesses on the beam
axis and at the position of 20 cm from the beam axis using ^"U and 2)2Th fission counters, as
- 7 -
. / A M I - l)uln/V.t>(U> fXi OOfi
shown in Figs, 20 and 21, and given in Tables 25 and 26 for 43- and 68-MeV p-Li neutrons.
The uncertainties of the measured data shown in the figures include the counting statistics of
the fission counters and neutron intensity monitor. The reaction rates indicate the integrated
neutron flux in the energy region above the threshold energy of the fission reactions: about 1
MeV,
In Table 27 the differences of neutron reaction rates measured by 7LiF and hi"LiF TLDs
in the iron shield arc given for 43- and 6K-McV p-Li neutrons. The differences arc dominated
by the neutron in the energy region up to 1 MeV as shown in Fig. 7. The errors of the
measurements are the counting statistics of each detector and neutron intensity monitor.
The measured nculron reaction rales in the iron shield are shown in Fig. 22 and given in
Table 28 using SSNTD for 43- and 68-MeV p-Li neutrons. As shown in Fig. 8, the efficiency
of the deteclor is dominated by the neutron in the energy region up to about 10 MeV. The
uncertainties of the measurements include the counting statistics of etch pits and neutron
intensity monitor.
The combination of the reaction rates measurements covers the whole energy region up
to the energy of peak neutrons produced by the neutron source, and the results of these
measurements are effective to confirm the integrated neutron flux in each energy region.
3.4 Neutron dose equivalent
The neutron reaction rates measured by a rcm counter, made by the Fuji Co. Ltd. arc
tabulated in Table 29 as a reference of neutron dose equivalents. Neutron dose equivalents were
also estimated from the neutron spectra above 10 MeV measured by the BC501A detector and
the neutron spectra up to 10 MeV by the Bonncr ball counter by multiplying the 1CRP21
ncutron-flux-to-dosc conversion factor22, «s given in Table 30. The neutron dose equivalents
arc compared with the neutron reaction rates measured by the rcm counter in Fig. 23. The
measured reaction rates by the rcm counter arc lower than the evaluated values behind the iron
shield of 20 cm thickness, while higher behind the iron shield of 100 cm thickness. The
discrepancy is caused by the response function of the rcm counter. The detector docs not have
the same response function as the dose conversion factor in the energy regions above 20 MeV
and between a few hundred kcV and a few kcV.
_ a _
HO-OOfi
4. SUMMARY
The spatial distributions of neutron energy spectra and reaction rates behind and inside
the iron shields up io 130 cm were measured for 43- and fi8-McV p-Li neutrons, which cover
the energy region between K)"1 cV and the energy of peuk neutrons generated viu the 7Li(p,n)
reaction using five kinds of detectors: the BC501A detector, the Conner ball counter, aHU andl12Th fission counters, 7LiF and mLW TLDs and SSNTD.
The data measured absolutely were tabulated in this report in order to estimate the
accuracy of the calculation code and cross section data set in the intermediate energy region.
As shown in figures in this report, the energy spectra measured using the quasi-monocncrgctic
neutron source give useful information for investigating the clastic and inelastic scattering
reactions respectively, and the spatial distributions behind the iron shields obtained using neutron
beam arc valuable for studying the angular distribution of the scattering reaction. The
measurement in the wide energy range provided the neutron dose equivalents behind the Iron
shields due to the intcrmcdiatc-cncrgy neutrons.
ACKNOWLEDGMENTS
We wish to thank the operation staff of TIARA for the cyclotron operation. This work
has been supported by the Univcrsitics-JAERI Collaborative Project Research Program.
17. Usowski P.W. ct at.: "Neutron fadueecl fission Cross Section Kates for "" 'Hi , »* ' » » u ,2 J ' N p and " ' P u from 1 to 400 McV", I'roc. Int. Conf. Nuclear Data for Sci. and Techno!.,
Mito, Japan, p.97-99 (1088).
18- Lisow.ski P.W. el al.: "Fission Cross Sections in the Intermediate Energy Region", Proc. Spec.
Meet, on Neutron Cross Section Standards for the Energy Region above 20 McV, Uppsala,
Sweden, 21-2:1 May, 1091, p.177-180 (1091).
19. llashiktira II,, Ihiikawa K., Tanaka S, and Kondo K.: "Calculation of Neutron Response of
Thermolumincscent Dosimeters", J. Faculty of Eng., Univ. of Tokyo, 39(1), 7 (1987).
20. Nakanc Y.: private communication.
21. Dickens J.K.: OKNL-6463, "SCINFUI/ A Monte Carlo Based Computer Program to
Determine a Seinlillalor Full lincrjjy Uesponsu to Neutron Detection for En Bclwccn 0.1 and
80 MeV: Program Development and Comparisons of Program Predictions with Experimental
Data" (1988).
22. "Data for Use in Protection Against External Radiation", Ann. ICRP, 17, 2f.\ (1987).
- 1 1 -
-JAMM-Diita/Coilo 90-005
T a b l e 1 DiniGi is io i i s of t h e i r o n s h i e l d a s s e m b l y a n d a d d i t i o n a l c o l l i t i m t o r ,and d e t e c t o r p o s i t i o n s .
e Solid s t a t e nuclear track detector.The 15C5O1A, Hornier bal l , f ission and rem detectors were used for measurements behind theiron shields, and the TLD and SSNTD were used for measurements inside the iron shie lds ofmaximum thickness.
- 1 2 -
.JARRI- D/itn/Corio 1)0-000
Tub ID 2 Atomic compos)lions of the ironshield and the surrounding concrete.
Material Atom
Iron Iron
Concrete llydrojjcnOxygon.Sod i um
MagnesiumAluminumSilicon
I'otassiumCalcium
Iron
Atomic DensityC l o s e r 3 )
8.487
1.4984.1880.1230.0620.3121.1100.0380.4300.141
Table 3 Source neutron energy spectrum via the 7Li(p,n)reaction by 43-MeV protons.
Table \ Source neutron energy spectrum via the 7Li(p, n)reaction by G8-MeV protons.
Energy(McV)
5.00EI00*O-OOI'11007.00EK)08.00KIO09.00I': tool . O O E i O i1.10BI01l . 2 0 E * 0 lI.30E10!1 . 4 0 E » O II.50EIOIJ.flOEiOlI.70I-HOI1.80EI0II.OOEtOl2.00EMM2. lOEtOI2.20EKJI2.30Ef012.40EI012.50Ef012.80E1012.70EMH2. 80E»012. 90EV013.00EJ013. lOEfOi3. 20KI-0L3.30EI0I3.40E(0l3.5OEtOI3.60Ei013.70EKJI3.80EJ0I
Table 8 Cal cilia led neutron response of solidstate nuclear track detector (TS-1GN),
Energy(MeV)
1- O O K O l2 . 0 0 E 0 13.5015 014.35E-0I5. OOK-Ol6.00E-OI8.00E011. OOKfOO1.2215(00I.32EI00l.G5EiO02.00EIOO2.077EI02.35EIO02.81515102.944EI03.0015(003.21Ef00
Response(I ' i l s /n)
3.64315-044.91515-045.325E-046.58915-045 . 0 I 0 E 0 45.33915045.52IE-046.271B-046.015E-046.948E-047.587E-047.06915 048.29315-047.36815-048.92815 048.66415-047.96415-048.7C9E-04
10 cm (urn2.035E?O6.808E»01.373EfI.8S0K*I.809E?I.5I5E'I.I72K-7.727F.'O4.999E'OI.45GK-05.002K'05.7O4E'OG.258KfOO.583EtO6.70^06«77OE'O6.952F/07.3O4E'O7.68GE»07.89DE»07.8G2E'O7.B30F/07.285E-06.854E*0G. 3161/05.8C7E-05.625F.-05.7I2F.-05.895F.'OS.828EfO5.494E-05.223E'O5.222E«05.4O5E'O5.652E-05.974E-0G.G29F.-07.374E-0
ax (H2.287E-1L203E I9.192E-21.026E-18.3B4E-21.I54E-I2.34IE-13.222E IL 30GE II.693E II. GIGE IL237E IL040K-I8.58 IF.5.688K3,388K3. G75E6.95 IE-2.II0K I.3131: I.2I8E I
Measured neutron spectra behind 20cm thick Iron by theBC501A detector for 43-MeV p-Li neutrons.
Energy(eV)
4 4Fi7'4.3E(74.2Ef74. IEt7'. OE * 73.9Et73.8Et/3.7E>73.0Ef73.5Et73.4E(73.3Et73.2KI73. Wtf3.0Ef72.9Ef72.8Et72.7Et72.GEf72.5Ef72.4Et72.3EI72.2E»72. IE»72.0E»7l . 9 E f 7I.8F.»7I.7E»7I .6E»7I.5E>7l . 4 E r 7l . 3 E t 7I . 2 E » 7t . I E > 7I.OEf7O.OE'G8. OK'G7.0E»66.0E'65.0EtG
Tablo 12 Muasurcd neutron spectra behind 40cm thick Iron bythe UC501A detector for 43-MuV p-Ll neutrons,
Energy(eV.) (n/
4.4EI7*4.3Et74.2Ef74.1E»74.0E»73.91^73.8Ef7Qt { \'j i I
a6E»73.5EI73.4Ef73.3Ef73.2E»73. l E f 73.0E»72.91'>72.8EJ72.7Et72.6E»72.5Ef72 .4E»72. mi2.2Et72.IE (72.0Et71.9Et7l . 8 E f 71.7Et7I . 6 E f 71.5Ef7I .4E H1.3Ef7l.2Ef7i. miI .OEf79.0Et68.0E>67.0EI66.0Et6S.0E>6
* Read as
Neutron FluxumVUstharijy/jiC)
beam axis8.705EH
. 9 4 2 E I 23.922EI25.260EI24.59IEI22.54IEI28.99IEH2.836EU2.073EI)2.562EH3. I05EH3.532EU3.842EH4.055EH4. 183EM4.234f)t I4. 217EH4. 157EH4.080EHi . O O l E f l3.912EU3.807EU3.685EU3.559EH3.418EU3.227EH2.941EH2.568EU2.183EHI.882EHI.699EH1.587EH1.465EH1.284EH1.069Efl8.595EfO6.529EK)5.532EfO6.227BfO
Table 30 Measured neutron reaction rates using the DC50IAand (tanner ball detector for 43- and 68-McV p-Lineutrons.
I'osilion' Reaction rate Position Reaction rule(cm) (I.SV/IC) (cut) («.Sv/«C)
2040100
43 M1.30I.60E-I'3.25F.3
2040100
G8 He3.095.29E1. GOF,
V
12
• Thichncss of iron shields.* feud us 1.60 x 10 '.
3t
(a) TOP VIEW
\ shielding wall (concrete)
experimentalassembly
7Li target 232Th-FC
P + ^ " | rZjdearingNmagnet
en
filler (iron ball and iron sand)
units in cm
Fig. 1 Cross sectional view of the TIARA facility withthe experimental arrangement.
(b) SIDE VIEWadditional
iron collimatoriron
shield
Fig.2 Top view and side view of experimentalarrangement for the iron shield withadditional iron collimator.
.JAKUI-lMu/Cudu Ofi-005
BC501A PM BASEDynode
PA DLA
Anode
HV
SCA
DA
CFDR1IC
sealer
gale.LO ADC1
gatey=r. LO ADC2
Istart
TAC ». i» L0 ADC3
RF trigger •- CFDJstop
Flg.3 Block diagram of the electronic circuits. PA:pre-amplifier, DLA: delay lineamplifier, SCA: timing single channel analyzer, DA: delay amplifier, RIIC:risc-tiine-to-pulse-height converter, CFD: constant fraction discriminator,TAC: tliae-lo-amplitude converter, LO:linear gate stretcher, ADC; analog-to-digital converter. The sealer was used for counting the number of realevents from the detector in order to estimate the counting Joss.
2xlOJ
u
1.5xlO
lxlOJ
5xlO8Cou
1 i • i ' r • \lr:- 68MeV p - Li
43MeV p-7Li
,- I..'0 10 20 30 40 50 60
Neutron Energy [MeV]70 80
Fig.4 Source neutron spectra generated via the 7Li(p,n)reaction by 43- and 68-MeVprotons. The spectra were measured by the time-of flight methods with theBC501A scintillation counter and absolutely normalized by the measurementsusing the recoil-proton counter telescope.
- 3 6 -
JAIWI-PiiUi/Codu Ofi-(
10'
,o«
llO"1
ao
,-2
I 1 I I I '
Neutron response of Bonner Bull detector
I., S N
bare1.5cm thick3.0cm thick5.0cm thick9.0cm thcik
i . . 1
10" 102 10'1 10'1
Neutron Hncrgy (cV)10"
Fig.5 Neutron responses of the Bonner ball counter for each moderator thickness:bare, 1.5, 3.0, and 9.0 cm. The almost responses were calculated by Uwaminoet al. from adjoint calculations using the ANISN code except for the detectorwith 1,5-cm thick moderator. The response for the detector with 1.5-cm thickmoderator was estimated by Ishikawa et al.
U
10Neutron Energy (cV)
10° 10'
Fig.6 Fission cross sections of 2 3 HU and 2:i2Th. The cross sections up to 20 MeV istaken from JENDL-3, the cross sections between 20 and 400 MeV have beenmeasured by Lisowski et al.. and above 400 MeV have been calculated by himusing the HETC code.
- 3 7 -
Ofi-OOfi
10*
ej j j j 1 p
Responses of 7LiF and niltLiF TLDs
. I . . i . . i . . i . I . . i .io~(l io"5 io"r io"J i o r \orl~ i
Neutron Energy (MeV)
Fig. 7 Calculated neutron responses of 7l,iH and n " L i F TLDs usinga code developed by llasliikura e l a l .
10
c
s
•g
coa-
10
Neutron response of solid state nuclear track detector
TS-16N
,-4
10rl 10"Neutron Energy (McV)
10'
Fig.8 Calculated neutron responses of solid state nuclear trackdetector (TS-16N) using the SSNRES code.
- 3 8 -
10*
105
1 0 -
10"
43MeV p-Li neutrons on Iron
100cm (hick
107 2Neutron Energy (eV)
Fig.9 Measured neutron spectra by the BC501A detectorbehind various thickness of iron on the beamaxis for 43-MeV p-Li neutrons.
io-
10'
J2I
10"
43MeV p-Li neutrons on 0cm thick Iron
107 ^Neutron Energy (eV)
Fig. 10 Measured neutron spectra by the BCsOlA detectorbehind 0-cm thick iron at the positions of 20 and40 cm from the beam axis for 43-MeV p-Li neutrons.
T
cc
10"
43MeV p-Li neutrons on 10cm thick Iron
40cm from beam axis (xO.l)
107 I 5Neutron Energy (cV)
Fig.11 Measured neutron spectra by the BC501A detectorbehind 10-cm thick iron on the beam axis and at thepositions of 20 and 40 cm from the beam axis for43-MeV p-Li neutrons.
to1
=0
to-'
IO1
10°
43MeV p-Li neutrons on 20cm thick Ironr
U-^H
io7 =Neutron Energy (eV)
Fig. 12 Measured neutron spectra by the BC5QU detectorbehind 20-cm thick iron on the beam axis and atthe positions of 20 and 40 cm from the beam axtsfor 43-MeV p-Li neutrons.
r
10J
43MeV p-Li neutrons on 40cm thick Iron
10s
oNeutron Energy (eV)
Fig. 13 Measured neutron spectra by the BC501A detectorbehind 40-cm thick iron on the beam axis and atthe positions of 20 and 40 cm from the beam axisfor 43-MeV p-Li neutrons.
10'
10'
6SMeV p-Li neutrons on Iron
-t**H*F '40cm thick
130cm thick
107
Neutron Energy (eV)
occ:
I
Fig. 14 Measured neutron spectra by the BC501A detectorbehind various thickness of iron on the beam axisfor 68-MeV p-Lx neutrons.
toI
100
a
3
X
c
s1
6SMeV p-Li neutrons on 0cm thick Iron
20cm from beam axis
107
10s
Neutron Energy (eV)
Fig. 15 Measured neutron spectra by the BC501A detectorbehind 0-cm thick iron at the positions of 20 and40 cm from the beam axis for 68-MeV p-Li neutrons.
io4
68MeV p-Li neutrons on 20an thick Iron
10'
20cm from beam axis
40cm from beam axis
Io
Neutron Energy (eV)
Fig. 16 Measured neutron spectra by the BC501A detectorbehind 20-cm thick iron on the beam axis and atthe positions of 20 and 40 cm from the beam axisfor 68-MeV p-Li neutrons.
CMI
104
u
iou
6SMcV p-Li neutrons on 40cm thick. Iron
107
40cm from beam axis
Neutron Energy (eV)
Fig. 17 Measured neutron spectra by the BC501A detectorbehind 40-cm thick iron on the beam axis and atthe positions of 20 and 40 cm from the beam axisfor 68-MeV p-Li neutrons.
io5
104
10u
3
10"
10"
43MeV p-Li neutrons on Iran
20cm thick (xlOO)
100cm thick
• J I -' -I •J J • •
10"' 10° 10l 1O1 103 104 10s 10* 10T
Neutron Energy (eV)
CO
I
Fig. 18 Measured neutron spectra by the Bonner ball counterbehind various thickness of iron on the beam axisfor 43-MeV p-Li neutrons.
10e
10s
104
10'
"I 1 1 1 1 1 T"""I
68MeV p-Li neutrons on Iron
...j .....J ,..,,,110"' 10° 10l 102 103 10"1
I I
Vf 10°Neutron Energy (eV)
10'
Fig. 19 Measured neutron spectra by the Bonner ball counterbehind various thickness of iron on the beam axisfor 68-MeV p-Li neutrons.
b
fact
ion
105
104
103
102
101
10°
in-1
—i—i—
r
: \
i N
- /
-
i i
- r - i—|
Fission
43MeV
- o -
\
\
• i i
—i r— i i i i
Reaction Rates
p-Li
? Ui > s U
\
neutrons on
beam axis20cm frombeam axis20cm from
x
• • *-Iron :
beam axis
beam axis •
-.
-
-.
} ' *
0 50 100Shield Thickness (cm)
150
Fig.20 Measured fission reaction rates of 2 3 8U and 232Thbehind iron on the beam axis and at the position of20 cm from the beam axis for 43-MeV p-Li neutrons.
noC3
I
en
L
13a
105
10*
3
102
101
10°
n"1
t Fission Reaction Rates
V\ 68MeV p-Li neutrons on\ \ —o— 2X2Th beam axis
\ \ —A— -fh 20cm from*3\ -«•--- TJ beam axis
\ \ ...A— u 20cm from
- \
- %
V, , i , i . . i , i
-
Iron
beam axis
beam axis
-
-
_
1 r t
50 100Shield Thickness (cm)
150
Fig.21 Measured fission reaction rates of 2 3 8U and 232Thbehind iron on the beam axis and at the position of20 cm from the beam axis for 68-MeV p-Li neutrons.
(J
I
Rat
e (P
iR
eact
ion
101
10°
10"1
io-2
\
\\ \
43
t %
. . . . . .
Reaction Rate of
V*
\ \
\ \
\ \ 68 MeV
\ \MeV \ \
\
\ \
\
> • ! • • > •
| i . t .
SSNTD
-
-
•
\
\
0
Ta
oocc
CO
I
50 100Shield Thickness (cm)
150
Fig.22 Measured reaction rates of solid state nucleartrack detector in the iron shield on the beamaxis for 43-and 68-MeV p-Li neutrons.
enI
u
10-1
oQ
s2"3CJ
Z10,-2
10-3
Neutron dose equivalent
43 and 68MeV p-Li neutrons on Iron
Fuji rem counter 43MeVFuji rem counter 6SMeVBC+Bonner 43MeVBC+Bonner 68MeV
oc
to
50 100Shield Thickness (cm)
150
Fig. 23 Measured neutron does equivalent by the rem countermade by Fuji Co. Ltd. for 43-and 68-MeV p-Li neutrons.In this figure the measured neutron does equivalentby the BC501A and Bonner ball detectors are also shown.