Transcript hp.ujf.cas.cz

XXI INTERNATIONAL BALDIN SEMINAR ON HIGH ENERGY PHYSICS PROBLEMS
Studies of Deuteron and Neutron Cross-sections Important for ADS
Research
(XXI Baldin seminar)
Vladimír Wagner
Nuclear physics institute of CAS, 250 68 Řež, Czech Republic, E_mail: [email protected]
for collaboration “Energy plus transmutation”
(Russia, Belarus, Germany, Greece, Poland, Ukraine, Czech Republic …)
Deuteron reaction cross-section measurements
Neutron reaction cross-sections measurements
Production of 24Na on aluminum foil by deuteron beam
Only about this reaction are cross-section data, but only scarce. → uncertainty 10 %
December 2011 set of QUINTA irradiations
2
1.9
2 GeV deuterons
1.8
Very good agreement – we have approved values
1.7
1.6
1.5
1.54(7)·1013 deuterons
1.39(4)·1013 deuterons
1.97(10)·1013 deuterons
2 GeV
4 GeV
6 GeV
1.4
1.3
1.2
1.1
1
0
1
2
3
4
5
Deuteron integral [1013 deuterons]
2
1.9
Cross-section uncertainty – 10 %
6
Deuteron integral [10 13 deuterons]
Deuteron integral [1013 deuterons]
Beam integral determination by means of aluminum foils
4 GeV deuterons
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
2.5
2.4
2.3
2.2
2.1
2
1.9
1.8
1.7
1.6
1.5
6 GeV deuterons
0
0
1
2
3
4
5
6
1
2
3
4
5
6
Beam intensity [-]
December 2011 irradiations
1.60E+13
1.58E+13
1.56E+13
1.54E+13
1.52E+13
1.50E+13
1.48E+13
1.46E+13
1.44E+13
1.42E+13
1.40E+13
1 GeV
4 GeV
1 GeV deuterons
0
1
2
3
4
Only statistical
uncertainties
5
6
7
8
9
Zhuk:
Number of measurement [-]
1 GeV
4 GeV
2.15E+13
2.10E+13
Beam intensity [-]
1.533(9)·1013 deuterons
1.932(10)·1013 deuterons
1.47 ·1013
1.96 ·1013
4 GeV deuterons
2.05E+13
2.00E+13
1.95E+13
1.90E+13
1.85E+13
1.80E+13
1.75E+13
0
2
4
6
8
Number of measurement [-]
10
12
Necessary – all data
with uncertainties
Description of all
correction calculation
(coincidences, self
absorption, size of
sample)
Beam intensity [-]
March 2012 irradiations
2.00E+13
1.98E+13
1.96E+13
1.94E+13
1.92E+13
1.90E+13
1.88E+13
1.86E+13
1.84E+13
1.82E+13
1.80E+13
1 GeV deuterons
Number
of deuterons
1 GeV
4 GeV
8 GeV
1.886(8)·1013
2.796(26)·1013
0.565(6)·1013
Preliminary
0
1
2
3
4
5
6
7
Zhuk
KH1
KH2
JINR
3.00E+13
2.95E+13
2.90E+13
4 GeV deuterons
2.85E+13
2.80E+13
2.75E+13
2.70E+13
2.65E+13
2.60E+13
0
1
2
3
4
5
Number of measurement [-]
6
7
8
Only statistical
uncertainties
1 GeV 4 GeV
8
Number of measurement [-]
Beam intensity [-]
Energy
1.9
1.8
1.8
1.87(10)
2.7
3.5
2.7
2.65(13)
8 GeV
0.37
0.49
0.37
0.55(4)
Studies of relativistic deuteron reactions on natural copper
Common irradiation of aluminum and
copper foils
Production of different radionuclides
Some deuteron energies were measured
more times
Energy range of deuteron beam
from 1 GeV up to 8 GeV
yield of radionuclide
More measurements of copper sample
in different times (possibility split
influence of short lived and long lived
isotopes with the same energy line – 43K
and 43Sc, 56Co and 56Mn, 48Sc and 48V)
and on different detectors with different
geometry (suppression of systematic
uncertainties influence)
March 2012 – 4 GeV
2.4E+08
2.4E+08
2.3E+08
2.3E+08
2.2E+08
2.2E+08
2.1E+08
52Mn
744 keV
2.1E+08
2.0E+08
0
2
4
6
8
10
Ratio of 1 GeV measurements
Comparison of different measurements with the same deuteron
energy
1.3
Comparison of two measurements
with 1 GeV neutron beam
1. December 2011
2. March 2012
1.2
1.1
1.0
0.9
Mean value of ratio: 0.969
0.8
0.7
0.6
Ratio of 4 GeV measurements
0
2
4
6
8
10
12
14
Comparison of three measurements
with 4 GeV neutron beam
1. March 2011
2. December 2011
3. March 2012
1.3
1.2
1.1
1.0
0.9
Mean value of ratio:
1./2. 0.884
3./2. 0.926
0.8
0.7
0.6
0
2
4
6
8
10
12
14
Obtained deuteron reaction cross-sections on natural copper
45.0
16.0
40.0
14.0
58
35.0
Cross-section [mbarn]
Cross-section [mbarn]
57Ni, 58Co, 56Co, 55Co, 56Mn, 52Mn, 48Cr, 48V, 48Sc, 47Sc, 44mSc, 43Sc
Co
30.0
25.0
20.0
and 43K
52
12.0
Mn
10.0
8.0
6.0
15.0
0
1
2
3
4
5
6
7
8
4.0
9
0
Deuteron energy [GeV]
1
2
3
4
5
6
Deuteron energy [GeV]
7
8
9
3.0
43
2.5
K
Cross-section [mbarn]
Cross-section [mbarn]
1.5
2.0
1.5
1.0
0
1
2
3
4
5
6
7
Deuteron energy [GeV]
8
9
1.3
57
1.1
Ni
0.9
0.7
0.5
0
1
2
3
4
5
6
Deuteron energy [GeV]
7
8
9
Measurement of neutron reaction cross/sections
Quasi-monoenergetic neutron source:
protons from cyclotron + lithium target
Beam-line
NPI ASCR Řež: Energy range 18 -37 MeV,
neutron intensity ~ 108 neutron cm-2 s-1
TSL Uppsala: Energy range 25 – 200 MeV
neutron intensity ~ 105 neutron cm-2 s-1
Advantage of two neutron sources: very wide energy
range, partial overlap – better estimation of
systematical uncertainties
Graphite
stopper
Samples
Li-target
Yttrium cross-section measurement
Methodical measurement – neutron energy 32.5 MeV (only reactions (n,2n) and (n,3n)),
May 2011, to prepare systematic study of yttrium reactions using the NPI neutron source
Yttrium – good material for activation
detector
Used by “Energy+Transmutation”
collaboration
Very scare data about cross-sections
87mY
T1/2 = 13.38 hours 380.79 keV
ε+β+
9/2+
1.57(10) % <<
98.43(10) %
No data about cross-sections of isomeric
state production
Long irradiation, intensive beam,
only limited number of samples →
possibility to measure yttrium sample
many times to study systematic
uncertainties of gamma
measurements
Concentration on isomeric state 87mY
ε+β+
87Y
1/2-
T1/2 = 79.8 hours
Reaction (n,3n) - production of isomeric
and ground state of 87Y
87mY
N1  N01e


1
1
 N 01 e 2 t 
 N 01e 1 t
87Y N 2   N 02 
1  2
1  2


1 t
9
Number of radioactive nuclei [10 ]
1.6
16000000000


1
N   N 02 
 N 01 e 2 t
1  2


14000000000
1.4
12000000000
1.2
Experimental
points
■ - 87Y
♦ - 87mY
10000000000
1.0
0.8
8000000000
N02
N = N01exp(-λ2t)
N01
0.6
6000000000
0.4
4000000000
N = N01exp(-λ1t)
2000000000
0.2
0.0
0
0
50
100
150
Time after end of irradiation [hours]
200
87mY
N1  N01e


1
1
 N 01 e 2 t 
 N 01e 1 t
87Y N 2   N 02 
1  2
1  2


1 t
N01=
N 02 
6.05(8)109
1
1  2
 N 01 
 14.38(11) 109
N02= 7.12(21)109
Number of radioactive nuclei
1.E+11


1
N   N 02 
 N 01 e 2 t
1  2


Experimental
points
1.E+10
■ - 87Y
♦ - 87mY
1.E+09
1.E+08
N = N01exp(-λ1t)
1.E+07
1.E+06
0
200
400
600
800
Time after end of irradiation [hours]
1000
Cross-section of 87mY and 87gY
Higher threshold near to neutron energy → 93 % of radioactive nuclei is produced by
peak, only 7 % by background
Uncertainties of proton beam integral and neutron spectra description
are about 10 - 15 % > gamma spectroscopy uncertainties
σ(87mY) = 578(56) mbarn
900
σ(87gY) = 203(25) mbarn
89Y(n,3n)87Y
89Y(n,2n)88Y
case
case
800
cross-section [mbarn]
Background production
subtraction
87Y
87mY squares - our data
700
lines - TALYS
600
87gY
500
87Y
400
- EXFOR
300
200
100
0
0
10
20
30
Neutron energy [MeV]
40
Reaction 89Y(n,2n)88Y
Neutron peak - only 34.8 % of production, 65.2 % of radioactive nuclei produced by background
1.8
EXFOR
88Y
1.6
TALYS 1.2
Cross-section [barn]
1.4
our data
1.2
1
0.8
0.6
0.4
New measurements next weeks
0.2
0
0
5
10
15
20
25
Neutron energy [MeV]
30
35
40
New measurements of neutron cross-section on yttrium
together with Polish colleagues
Improvements:
1) Every irradiations two yttrium samples, one
foil and one pressed tablet
2) Big number of measurements of every sample
(very important for isomeric state
measurement)
3) Measurement in different sample distance to
detector
Measurement is in the framework of
ERINDA
Four irradiations:
First two during weekend:
Energies 18 and 35 MeV
Next two during first half of October:
Energies 26 and 29 MeV
Conclusions
•
Many cross-sections of deuteron and neutron reactions with different materials
are needed (very scarce data at experimental data bases).
•
We used Quinta measurements to obtain cross-sections of relativistic deuterons
reactions on copper.
•
The crucial is determination of beam integral (for all data). The common analysis
of all monitor data and determination of common final of beam integral is
necessary. We made this only fo first Quinta irradiation (March 2011)
•
The set of thirteen reactions on copper was studied and cross-sections were
determined within energy range from 1 GeV up to 8 GeV.
•
The quasimonoenergy neutron sources are ideal possibility to obtain crosssections of reactions which we use for activation measurement of neutron field.
•
We started set of measurements of yttrium samples together with our Polish
colleagues. The ERINDA project and NPI Rez neutron source are used.
BIG THANKS
to students
Diploma and PhD students:
Ondřej Svoboda
Jitka Vrzalová
Martin Suchopár
Petr Chaloupka
Other students:
Ondřej Sláma
Anne Laredo
Daniel Wagner
and also all colleagues
and JINR Dubna Nuclotron
people