Transcript Document

Cosmogenic induced activity
IDEA (Integrated Double-beta decay European Activities)
Task coordinators: Maura Pavan, Susana Cebrián
Susana Cebrián
[email protected]
University of Zaragoza (Spain)
Zaragoza, 7th-8th November 2005
 Implementation plan
9.R2 - Table 1 – IDEA - Second 18 months Execution Plan
WP
Task
13st to 18th month
(1.04.2005-30.09.2005)
- Up-grade and
development of
simulation codes
Tasks
4
B1
19th to 24th month
(1.10.2005-31.03.2006)
- Upgrading of existing
codes for n/p activation
- Design of further n/p
activation tests on Ge
and TeO2
25th to 30th month
(1.04.2006-30.09.2006)
- further n/p activation
experiments
- Start-up of tests at CERN and other labs on Ge
and TeO2
Milesto
nes and
Delivera
bles
- Upgraded codes for n/p activation and related
technical report
- progress report
Outline of the talk
• Simulation-based work
• Irradiations tests
• Outlook and summary
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
 General issues
MEETINGS:
Common Meeting on Monte Carlo studies (JRA1 / N3 / JRA2) held in Zaragoza,
on 15th September 2005
(minutes and transparencies available at http://www.unizar.es/ilias/JRA1/05.htm)
• Interest on copper activation by JRA1
• Interface with GEANT4 Collaboration
CONFERENCES:
Talk on “Cosmogenic activation in germanium Double Beta Decay
Experiments” by s. Cebrián et al at TAUP2005 Conference, Zaragoza (Spain),
September 2005
(available at http://ezpc00.unizar.es/taup2005/talks.htm)
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Simulation-based work
GOAL: Identification of the most reliable codes and of the weak points of
computations for treating our problems in order to improve them
In the first year …
Studies for relevant activation problems in DBD
using different codes and comparing with data when
possible: Te, Ge
In the last six months …
S. Cebrián, Cosmogenic Induced Activity
• Activation study for Cu
• Improvements in GEANT4
IDEA meeting, Zaragoza, November 2005
Activation study for Cu

Why copper?
• Common material in set-ups of rare event experiments
• A large amount of experimental data for production cross sections!

Similar work to that done for Te and Ge:
1.
Comparison of excitation functions to find the most reliable
evaluation for relevant products using:
• Measurements with beams:
protons: lots of data at EXFOR database
neutrons !!!: E. J. Kim et al, J. Nucl. Sci. Tech. 36 (1999) 29-40
• Calculations based on semiempirical Silberberg & Tsao formulas:
•
2.
YIELDX
Monte Carlo calculations:
MENDL-2 (using versions of ALICE)
p >100 MeV
p <200 MeV, n <100 MeV
Calculation of production rates of induced nuclei
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Activation study for Cu: excitation functions
YIELDX works very well
at E>200-300 MeV but
overestimates below
MENDL for n is above
results from Kim’99
MENDL for p gives good
agreement with
measurements at low energy
57Co
S. Cebrián, Cosmogenic Induced Activity
production in nat Cu
IDEA meeting, Zaragoza, November 2005
In MENDL predictions production by neutrons is
higher and with lower threshold than by protons
MENDL results for n seem to be
below Kim’99 data
Much worse agreement between
measurements and calculations
60Co
S. Cebrián, Cosmogenic Induced Activity
production in nat Cu
IDEA meeting, Zaragoza, November 2005
 Deviation factors
MENDL(n)
MENDL(p)
YIELDX
YIELDX
<100 MeV
<200 MeV
200-300MeV
>300MeV
56Co
3,6
1,8
1,1
1,2
57Co
1,4
1,1
1,4
1,1
58Co
1,3
1,8
6,8
2,9
60Co
1,4
2,6
2,0
1,6
1,5
1,5
1,5
5,0
3,6
1,7
1,8
1,3
1,3
1,9
54Mn
59Fe
2,5
46Sc
65Zn
1,7
At low energies
there can be
significant
differences in F
between
products
Our selection for the excitation functions in Cu:
at low energies (<100 MeV): MENDL results for neutrons, normalized to experimental
data when possible very important to reproduce experimental production rates!
at higher energies: experimental data for protons combined with YIELDX
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Activation study for Cu: production rates
 Cosmic neutron spectrum: parameterization based on measurements
E>20 MeV:
4.5 10-3 n/cm2/s
J. F. Ziegler, IBM Journal of Research and Development 42 (1998) 1.
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
 Production rates (kg-1d-1)
LE
ME
HE
COSMO
F&M '04
Heusser'05
972,3
19,9±2,6
56Co
2,6
+
18,0
+
2,3
22,9
57Co
29,7
+
55,8
+
2,8
88,3
58Co
90,4
+
65,7
+
3,5
159,6
60Co
81,8
+
14,2
+
1,4
97,4
54Mn
3,6
+
25,9
+
3
32,5
59Fe
4,3
+
1,9
+
0,3
6,5
39±10
46Sc
0
+
2,5
+
1,3
3,8
4,6±1,6
Contributions up to 100 MeV (LE), 1001000 MeV (ME) and above 1 GeV (HE)
30,5
155±35
131,5
142,6±7,8
25,7
2675,5
181±16
134,2
52,2
18,6±1,8
Calculations based on modified COSMO
L. Baudis, R. W. Schnee, NUSL White Paper, 2002
Deduced from experimental data (Fisher
et al., PLB 218 (1989) 257)
Measurements following a long exposure at
LNGS surface
J. A. Formaggio, C. J. Martoff, Annu. Rev.
Nucl. Part. Sci. 54 (2004) 361
G. Heusser, LRT2004, Sudbury, December 2004.
Thanks are due to G. Heusser for informing
us on their measurements
S. Cebrián, Cosmogenic Induced Activity
G. Heusser, M. Laubenstein, H. Neder, to appear
in “Radionuclides in the Aquatic environment” (Ed.
Povinec) Elsevier, 2005
IDEA meeting, Zaragoza, November 2005
 Production rates
LE
x 2.1
(kg-1d-1)
ME
HE
COSMO
F&M '04
Heusser'05
at LNGS
972,3
19,9±2,6
48,1
155±35
185,5
131,5
142,6±7,8
335,1
56Co
2,6
+
18,0
+
2,3
22,9
57Co
29,7
+
55,8
+
2,8
88,3
58Co
90,4
+
65,7
+
3,5
159,6
60Co
81,8
+
14,2
+
1,4
97,4
25,7
2675,5
181±16
204,5
54Mn
3,6
+
25,9
+
3
32,5
134,2
52,2
18,6±1,8
68,3
59Fe
4,3
+
1,9
+
0,3
6,5
39±10
13,6
46Sc
0
+
2,5
+
1,3
3,8
4,6±1,6
8,0
30,5
Differences are understandable if just
semiempirical cross sections are
considered: for 60Co low energy neutron
contribution is missed
Extremely high rates
justified by Chernobyl
58Co
production not understood:
measured production cross sections
for n and for p higher than for 60Co but
this is not true for production rates
Discrepancies for other products could be (qualitatively)
understood mainly due to the selected excitation
functions at medium energies: based on p measurements
not continuous with n measurements at lower energies
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
 Summary of the activation study in Cu
• Deviations between measured production cross sections (for p and even
for n) and calculations (using YIELDX and MENDL library) have been
evaluated for different products.
• Semiempirical calculations reproduce quite well cross sections above
~300 MeV, but they cannot be the only source of information to derive
reliable production rates
• For the production of some nuclei, the use at low energies of the excitation
function specific for neutrons is essential
• Apart from 58Co, some discrepancies between our calculated production
rates and the direct measurements at Gran Sasso could be understandable
and could be reduced if some information of cross sections for neutrons
at medium energies (hundreds of MeV) was available.
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Improvements in GEANT4
 Contact has been established between ILIAS MC working groups and the
GEANT4 Collaboration to pass on to them underground physics interests on
simulations
Ongoing validation effort regarding isotope production within the
GEANT4 Collaboration
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Calculations for Ge using GEANT4
 Irradiation experiment Aleksandrov’91 simulated obtaining production s
• with 660 MeV protons
• on natural Ge
• using different GEANT4 models (Bertini and Binary cascades) and
semiempirical YIELDX J. P. Wellisch, nucl-th/0306006, nucl-th/0306008, nucl-th/0306016
S. Cebrián, Cosmogenic Induced Activity
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IDEA meeting, Zaragoza, November 2005
 Global deviation factor from Aleksandrov’91 results
model
deviation factor F
YIELDX
1.87
GEANT4 (Binary)
5.88
GEANT4 (Bertini)
3.18
• YIELDX gives better agreement than GEANT4
• Bertini model seems to work better than Binary cascade, as found in Te
simulations (Heidelberg presentation) and in the GEANT4 Collaboration
validations
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Irradiation tests
GOAL: to measure the production cross-sections and/or rates of production
with n/p beams on the targets of interest
Essential to validate calculations with codes
In the first year …
Some crucial questions regarding activation in Te, Ge
were identified giving rise to possible irradiation tests
In the last six months …
• Experiment at CERN on TeO2
• Proposals for Ge experiment
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Experiment at CERN on TeO2
 Initial problem
1,E+02
COSMO predicted a high production
1,E+01
cross section
of 60Co in Te between
1-3 GeV
sigma (mb)
1,E+00
1,E-01
1,E-02
Disagreement with YIELDX calculations and
measurement for 1.85 GeV p at Berkeley by Bardayan’97
1,E-03
1,E-04
60Co
production in nat Te
1,E-05
10
100
1000
10000
100000
energy (MeV)
Silberberg &Tsao (YIELDX)
GEANT4
measurement Berkeley
modified COSMO
measurement CERN
Irradiation experiment proposed and already carried out at CERN with 1.4 GeV p
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
 Features of experiment
Beam (p) energy
Fluence
Sample mass
Te mass
1.4 GeV
1.65 1015 p/cm2
0.457 g
0.365 g
• Two long gamma countings (several days) performed
 Results
• Activation yields of many different products identified (Rb, Rh, Sn, In, Sb
isotopes) including 60Co
• Complete evaluation of production cross sections and comparison with
YIELDX calculations (together with results of a previous irradiation at 24
GeV also at CERN) underway
• 60Co production cross sections (mb):
energy (GeV)
CERN
24
1.14±0.19
1.85
1.4
Berkeley
preliminary!
CERN
YIELDX
1.15
0.63±0.15
0.85
0.40±0.06
0.77
Sensitivity of CUORE to 130Te DBD is not jeopardized by cosmogenic 60Co in crystals
and YIELDX calculations in good agreement with measurements
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Proposals for Ge irradiation experiment
 An irradiation experiment with germanium as target is being planned
• target sample: natural or enriched?
• projectile: n or p?
• energy beam: mono-energetic?
• facility and time: for irradiation and for gamma-counting
• to shed light on 68Ge activation (there are important discrepancies between
calculated and experimental production rates) low energy neutron beams would
be highly recommended
• the use of both natural and enriched targets would be advisable
 Several possible experiments have been analyzed:
• facilities, beam features, cost
• actvivity yields and possible counting
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
IRRADIATION
1
ITEP, Moscow, Russia
Facility
Beam
Svedberg Laboratory
(TSL), Uppsala, Sweden
800 MeV p on W target
Fully monoenergetic n
producing n with a
beam 20-175 MeV
continuous energy spectrum Fluence: 5 105 n/cm2/s (2Total fluence: 1015 p
30 cm , up to 106 n/s)
W target: D=5cm, L=3 cm
Availability
Gamma
counting
Cost
More info
2
Included. Possibility of sending
the sample for further
measurements.
Irradiation: 3000 €
Personnel: 3000 €+ 500
€/sample
Gamma counting: 150 €/day
Samples: 1.4$/mg 70Ge
(buying); 300-500 €/half a year
(renting)
“Pilot activation experiment at
ITEP”, V. Kornoukhov
3
Centre de Reserches du Cyclotron
(CRC), Louvain, Belgium
Quasi-monoenergetic n beam 20-65
MeV
Fluence: 1.3 104 n/cm2/s (10 cm ,
up to 2 106 total n/s)
Beam for therapy, industry and
basic research.
Deadlines for proposals: 15
October, 15 January
TARI access in 2004-2007
Not available.
Beam for industry and research.
Deadline for Proposals: December 2005
for operation in February-July 2006
Irradiation: 400 €/hour
+ sample
Irradiation: 516 €/hour for industry.
Offered free irradiation if proposal
accepted
+ sample
- http://www.tsl.uu.se
- On the beam and facility: L.
Andersson et al, Proceedings of
EPAC2004, Lucerne,
Switzerland.
- http://www.cyc.ucl.ac.be
- On the beam and facility: H.
Schuhmacher et al, NIMA 421 (1999) 284
- Irradiation experiment in Ge at CRC: J.
E. Naya et al, NIMA 396 (1997) 374.
S. Cebrián, Cosmogenic Induced Activity
4
Natural
irradiation
Cosmic
rays at sea
level
Possible.
Sample
IDEA meeting, Zaragoza, November 2005
YIELDS
1, ITEP
2, Uppsala
3, Louvain
4, Nat irradiation
5787
~25
~0.5
0.3 10-3
68
(for Ge, 1 g sample)
Activity
mBq
(for 1 g 70Ge)
(V. Kornoukhov)
(for nat Ge after 1 hour of
irradiation, assuming s=60 mb)
Activity ratios: 10000 : 50 : 1 : 0.001
 counting at 1077 keV
counts/day
(I=3%, =2%)
X-rays at 9.2 keV
counts/day
(I=39.7%, =100%)
(for nat Ge after 1 hour of (for nat Ge after 1 y of
irradiation, assuming s=60 irradiation assuming R=50
kg-1 d-1)
mb and completely
monoenergetic beam)
300
1.3
0.026
1.5 10-5
~2x105
~850
~17
~0.01
Only X-ray
counting
possible
Sample=detector approach:
+ higher efficiency for measuring the yield, allowing lower neutron fluxes
Very
massive
samples
required
- irradiation of components other than Ge crystal
- not easy continuity for enriched samples
PROS & CONS
Possibility of seeing other
activation products
Continuation with
enriched samples
Extrapolation of results
1, ITEP
2, Uppsala
3, Louvain
4, Nat irradiation
++
-
--
+
++
-
-
-
-
+
+
-
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
Outlook
9.R2 - Table 1 – IDEA - Second 18 months Execution Plan
WP
Task
13st to 18th month
(1.04.2005-30.09.2005)
- Up-grade and
development of
simulation codes
Tasks
4
B1
19th to 24th month
(1.10.2005-31.03.2006)
- Upgrading of existing
codes for n/p activation
- Design of further n/p
activation tests on Ge
and TeO2
25th to 30th month
(1.04.2006-30.09.2006)
- further n/p activation
experiments
- Start-up of tests at CERN and other labs on Ge
and TeO2
Milesto
nes and
Delivera
bles
- Upgraded codes for n/p activation and related
technical report
S. Cebrián, Cosmogenic Induced Activity
- progress report
IDEA meeting, Zaragoza, November 2005
Summary
 A study of activation in Cu using available experimental
data and different calculations is underway, allowing a better
validation of codes.
 GEANT4 has started a validation effort for isotope
production
 An irradiation test on Te has been carried out at CERN
and preliminary results are available for 60Co.
 Different options for an irradiation experiment with Ge
have been studied.
S. Cebrián, Cosmogenic Induced Activity
IDEA meeting, Zaragoza, November 2005
1000
production cross section (mb)
68Ge
production in nat Ge
100
10
1
10
YIELDX (Silberberg&Tsao)
MENDL-2 (n)
CEM95 (p)
GEANT4 LHEP_PRECO (p)
S. Cebrián, Cosmogenic Induced Activity
100
energy (MeV)
Aleksandrov'91
Horiguchi'83
HMS-ALICE (p)
GEANT4 LHEP_BERT (p)
1000
10000
MENDL-2P (p)
ISABEL (Majorana, n)
HMS-ALICE (n)
GEANT4 LHEP_BIC (p)
IDEA meeting, Zaragoza, November 2005