Transcript Underground Gamma-ray Spectrometry in HADES Mikael Hult Geel, Belgium

Underground Gamma-ray Spectrometry in HADES
Mikael Hult
Institute for Reference Materials and Measurements (IRMM)
Geel, Belgium
http://www.irmm.jrc.be
http://www.jrc.cec.eu.int
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Personnel involved in ILIAS
activities - status 1st half of 2005
• Uwe Wätjen (D), Sector Head Radionuclide Metrology, in EUROMET
Technical Committee Ionising Radiation, CCRI Section II
• Mikael Hult (S), Group leader low-level measurements, co-ordinator
of CELLAR,
• Gerd Marissens (B), Chief technician
• Joël Gasparro (F), Post doc. Fellow
• Werner Preusse (D), Visiting scientist
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The EU Institutions
Committee of the
Regions
Court of Auditors
European
Parliament
The Council of
Ministers
Economic and
Social Committee
Court of Justice
The European Commission
(the ‘College’ of Commissioners)
SG
...
RELEX
...
ENTR
...
ENV
….
SANCO
...
RTD
….... JRC
...
Directorates General: the “Commission services”
JRC Institutes: IHCP
IPSC IPTS IRMM …..
JRC can apply for funding from DG RTD like any other institution. The only restriction is
that JRC persons are not allowed to co-ordinate indirect actions
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Structure of the DG-JRC
7 Institutes in 5 Member States
IRMM – Geel, Belgium
- Institute for Reference Materials and Measurements
Staff:  250
IE – Petten, The Netherlands
- Institute for Energy
Staff:  180
ITU – Karlsruhe, Germany
- Institute for Transuranium elements
Staff:  250
IPSC - IHCP - IES – Ispra, Italy
- Institute for the Protection and the Security of the Citizen
- Institute for Health and Consumer Protection
- Institute for Environment and Sustainability
Staff:  350, 250, 370
IPTS – Seville, Spain
- Institute for Prospective Technological Studies
Staff:  100
Total staff: ~ 2200 people
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Olen – Geel – Mol - Dessel
5
5 km
IRMM
SCK•CEN + VITO (+ HADES)
Umicore
BR1 (700 kW) + BR2 (10 MW)
Canberra Semiconductor
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Nearby facilities
• Canberra Semiconductor – for HPGe detector assemblies
• Umicore – for Ge crystal growth
• IRMM – for radioactivity measurements (low-level or high
accuracy)
• IRMM – other facilities: LINAC, Van de Graaff, reference
facilities in analytical chemistry etc.
• SCK – HADES, 2 research reactors and analytical facilities
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GELINA : the Geel Linear Accelerator
Neutron measurements with very high energy resolution
using time-of-flight technique
n
U
e-
L
150 MeV
E
8
1
L
mv 2   
2
T
2
IRMM core competences &
research areas
Core competences
• Food analysis & bio-analysis
• Reference materials
• Chemical/isotopic reference
measurements
• Radionuclide metrology
• Neutron physics (LINAC, VdG)
Applied in the fields of
• Food safety and quality
• Biotechnology and health
• Environment
• Nuclear safeguards
• Nuclear safety
• Nuclear waste treatment
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HADES = High Activity Disposal Experimental Site
First shaft
Connecting gallery
Constructed 2003
Test drift
67 m
84 m
PRACLAY gallery
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0
Location of
IRMM’s ULGS
setup
{
223 m
Second shaft
Constructed 1999
Overburden:
~ 175 m sand
~ 50 m clay
39 m
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Detectors in HADES
Detector
name
Ge-2
Ge-3
Ge-4
Ge-5
Ge-6
Manufacturer
Eurisys
Eurisys
Canberra
Canberra
Canberra /
Ortec
Ge-7
Ge-8
Ge-9
Canberra
Canberra
?
Relative efficiency
Year
Crystal type
(%)
installed
n-type semiplanar
8
1995
p-type coaxial
60
1997
p-type coaxial (XTRa)
106
2000
p-type planar (BEGe)
50
2001
p-type coaxial
p-type coaxial (XTRa)
with inverted head
p-type planar (BEGe)
Well-type
80
2004
80
38
2005
2006
2006?
• Ge-8 is ordered (high resolution – low background at low energies)
• Ge-4 and Ge-7 will be placed in the same shield to form a sandwich detector
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2
Ge
Normalised counting rate (d-1 keV-1 kg-1 )
Gamma-ray background spectrum
10000
10000
10000
10000
10000
10000
3
10
1000
1000
1000
1000
1000
1000
100
100
100
100
100
100
1
10
1010
10
10
10
10
Felsenkeller~14
125 m
cmw.e.
lead
11
11
1
1
-1
10
~ 8 cm Cu
00
00
0
0
00
00
0
0
-3
10
HADES 500 m w.e.
00
00
0
0
00
00
0
0
-5
10
Gran Sasso 3800 m w.e.
00
00
0
00 0
00
0
0
500
500
500
500
500
500
1
3
1000
1000
1000
1000
1000
1500
1500
1500
1500
1500
2000
2000
2000
2000
2000
1000
1500
2000
Gamma-ray energy (keV)
2500
2500
2500
2500
2500
3000
3000
3000
30003000
3000
General comments on materials
Variability between batches
If you want to have a ULB HPGe you need to
select the materials yourself and have the
detector tested in a reputable deep
underground laboratory very near to a
manufacturer.
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Ge-production (i)
1) Raw material: residue from e.g. Zn-ore with 3-5% Ge
2) Reduction of Ge-oxide
Measurements
Resistivity
 Hall
 DLTS
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Zn-plant
Balen?
3) Zone-refinement
4) Czochralski growth
Resistivity
measurement
repeat
Ge-production (ii)
Reduction of Ge-oxide
Needs a powerful furnace. A bit difficult to put underground
but possible
Zone-refinement
12-13 days work (24/24)=> > 1 months without shift work
Relatively easy to put underground (“low power”, some gas)
Czochralski growth
2-3 days
Relatively easy to place underground
(small “low power”, some gas)
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214Bi
0.9
(222Rn-daughter)
Ge
Normalised counting rate (d-1 keV-1 kg-1 )
1.0
60Co
65Zn
0.8
0.7
g-energy: 1115 keV
0.6
0.5
Binding E (Cu): 8.98 keV
0.4
0.3
0.2
0.1
0.0
1080
1100
1120
1140
1160
Gamma-ray energy (keV)
1
7
1180
1200
What is underground?
Depth
(m w.e.)
< 10
Idiom
Characteristics
 The soft component (e, e+, photons) is strongly reduced but still plays a
Not underground
part.
or
 Very little reduction of muon flux and neutron induced by muons.
above ground
 Muon shields are useful.
Shallow
underground
 The soft component of the cosmic ray has vanished.
 The muon flux is reduced a factor of 5-50, but Muon shields are useful.
 There is still a significant flux of neutrons produced by muons (reduction
of factor 2-10).
 The activation of crystal and shield are still important factors.
100 – 1000
Semi deep
underground
 Cosmogenic activation can be neglected.
 A slight improvement can be obtained by discriminating against muons.
 The neutron flux is dominated by (,n) sources
> 1000
Deep
underground
 The influence of the cosmic rays can be neglected.
 The only source for neutrons are (,n) reactions.
10 – 100
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of radiation by depth
Attenuation Attenuation
of radiation
in earth’s crust
1.E-01
-1
10
muons
10
Secondary
neutrons
-3
1.E-03
Neutrons produced
in lead by muons
Intensity cm-2 s-1
Intensity (particlkes/cm 2/s)
HADES
1.E-02
-2
10
-4
1.E-04
10
Neutrons from
fission
and
(,n)
-5
1.E-05
10
1.E-06
0.01
0.1
0.1
1
1
10
10
Depth (meter water equivalent)
100
100
Depth (meter water equivalent)
Source: Gerd Heusser
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1000
1000
Low-level measurements – a growing field!
Isotopic fingerprints
Hiroshima
Neutrinos / bb
Reference materials
4%
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Al intercomparison
3%
JET
Tokai-mura
Safeguards
Neutron data
3%
Bkg+calibration
19%
Nuclear safeguards
3%
Decay data
Radiation Protection
Small samples
HADES
1999-2002
High temporal
(FP5)
Zn in GaAs
2%
BOREXINO
5%
Ref.measurements
resolution
60
Co in steel from
Hiroshima
3%
60
Co in German steel
1%
JCO accident
11%
Maintenance and new
installations
7%
Various
7%
210
Pb in lung cells
3%
2
0
Radioprotection
14%
210
Pb and Th in human
bones
15%
Benchmarking
Fast measurements
Radiopurity for detector
construction
 (E)
Why is this a current
 ( E ) issue?
R( E ) B( E )
FoM
=
Development in germanium detector technology
R( E ) B( E )
104
3 crystals in one cryostat
Figure of Merit (s1/2)
103
102
The first Ge(Li)
101
100
Coaxial
The first HPGe
Planar
10-1
1965
2
1
1970
1975
1980
1985
Year
1990
1995
2000
2005
Source: Physics World, January 2004, “Controlled Fusion: the Next Step”
By Gia Tuong Hoang and Jean Jacquinot
JET
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Collaboration of European Lowlevel underground LAboRatories
Mission: To promote higher quality and
sensitivity in ultra low-level radioactivity
measurements for the improvement of crisis
management,
environment,
health
and
consumer protection standards of Europe.
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CELLAR-Partners
• LSCE - France (-2200 m)
• LNGS - Italy (-1700 m)
• PTB - Germany (-925 m => -415 m)
• IRMM - EU (-225 m)
• University of Iceland (-165 m)
• VKTA - Germany (-50 m)
• IAEA-MEL - Monaco
• MPI-Heidelberg - Germany (-10 m)
• ARC-Seibersdorf – Austria (- 2 m)
+ associated partners
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CELLAR-actions
Setting up of a programme (in close
contact with ICRM LLWG) involving
actions like:
• Joint purchase and underground
storage of electrolytic copper. Testing of equipment.
• ‘Travelling detector’ - study of background at different
laboratories using one detector to better optimise
construction of detectors made from Ge, NaI and CsI
• Intercomparisons
of low-levels of activity (crisis
management and international equivalence)
• Joint publications describing state of
applications areas and future development
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the
art,
There is still work to do!
Low background - above ground
105
104
Felsenkeller
Gran
Sasso
ASSE/UDO
103
HADES
102
101
100
10-1
Modane
Muon fluence rate (a. u.)
Background counting rate (d-1 kgGe-1)
106
10-2
0
1000
2000
3000
Depth (m w.e.)
2
6
4000
5000
The future
Go even deeper!
105
104
Muon fluence rate (a. u.)
Background counting rate (d-1 kgGe-1)
106
103
102
101
100
10-1
10-2
0
1000
2000
3000
Depth (m w.e.)
2
7
4000
5000
Will some wealth from HADES
reach ILIAS?
YES If we can do like only Heracles
succeeded before .....
...... to take Cerberus for a walk
(= to manage to fulfil the
necessary EC formalities)
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