Transcript Diapositiva 1 - IDEA project

Status of the Se82 project
Selenium production
and purification
JRA2-ILIAS
Prague, April 20th, 2006, IDEA-N4 meeting
Dominique Lalanne
82Se
production: present status
PRESENT STATUS:
1. There is agreement between ITEP and
CNRS/IN2P3 about production of 2 kg of 82Se
(it was signed in February’05; end of agreement is
31 December 2006).
2. 1-st kg was ready in September’05.
3. 2-nd kg was produced in January’06. To be measured in Laboratoire
Souterrain de Modane this April 2006
First delivery of 1 kg of enriched Selenium from ITEP
Measurement of radio-element traces
Sample(
mBq/kg)
Masse
(kg)
Time
(h)
40K
60Co
137Cs
238U
235U
226Ra
228Th
228Ra
106Ru
82Se
1
300
< 14
0.8 ± 0.3
0.9 ± 0.3
90 ± 15
2.9 ± 5
< 1.5
3.7 ± 7
1.6 ± 5
24 ± 3
powder
Conclusions :
228Ra
and 228Th give the 208Tl contamination so
2 mBq/kg is a factor of 1000 too high for a source of SuperNEMO
226Ra
gives the 214Bi contamination
only a limit, so a more precise measurement would be usefull
108Ru
is a beta emitter of Q ~ 3 MeV so pollution is catastrophic !
purification !
Characteristics of the second kg
• Enrichment: 96.7 ± 0.3 %
• Other Se isotopes:
Isotope 74 76 77
78
80
%
-
3.3
96.7
± 0.1 ± 0.3
-
-
-
82
New opportunities for enrichment
Very important contact with ECP
(Electro-Chemical Plant, Svetlana) Zelenogorsk (Siberia)
 Much easier collaboration with this factory today
40 kg of enriched 76Ge for GERDA experiment
 Possibility of 2 kg of 82Se in this facility
(IN2P3 ownership)
 Enrichment of 100 kg of
in 3 years at ECP
82Se
is possible
Present cost: ~ 50 k€ / kg
 Distillation of 82Se possible in ECP
just after enrichment for highest purity
(distillation of 116Cd have been done in NEMO 3)
contact also for enrichment of Te in 130Te
ECP-ILIAS meeting
Orsay, March 9-10, 2006
Participants :
Dmitry Kononov, Yuri Kulinich, Elena Nikitina, ECP-Krasnoyarsk
Serge Jullian, Dominique Lalanne, Xavier Sarazin, LAL-Orsay
Alexander Barabash, ITEP-Moscow
Goal of the meeting
study of a possible production of enriched 82Se
in the ECP-Krasnoyarsk facility in order to test
the level of purity of the final product and
comparison to the level needed for the next
generation of Double Beta experiment.
Yuri Kulinich presented the possibilities in ECP-Krasnoyark.
For hundreds of kilograms it is without problems, the facility has the goal of
mass production. For example it is ~ 30% of Russian enriched Uranium
production and ECP is largest producer of stable isotopes in the world.
There are different units and the one devoted to enriched Selenium will be a
new one, never used before, so in principle with a low level of radioimpurities.
This facility is closely connected to units for chemical purification and
chemical treatment. Each new isotope needs special equipment and there is
for each a special unit dedicated to.
Dmitry Kononov is an expert in the chemical treatment of Selenium. For the
current Selenium production the level of chemical impurities at the output are
the following :
Thallium : 7. 10-11 g/g
Bismuth : 40. 10-11 g/g
Thorium : 6. 10-11 g/g
Uranium : 3. 10-11 g/g
(240 mBq/kg)
(360 mBq/kg)
-----------------------
Alexander Barabash (ITEP, Moscow) is responsible of the purity
of the post-enrichment process.
He will be allowed to spend as much time as needed at the site
to give the green light for production in clean conditions.
Especially on clean handling in clean air environment and clean
conditions, also on some tools or odds and ends being possibly
polluted or capable to induce pollution from outside.
The possibility of measurements in Modane Laboratory of some
parts of the equipment can be used for selection.
The agreement can be signed within 2 months for
a production of 1 kg by the end of year 2006.
INL, Hidaho, USA
Selenium purification
ILIAS-JRA2
Challenge : from NEMO3 to SuperNEMO
NEMO3 Backgrounds
 External :
 Internal :
214Bi
negligeable
: 60 mBq/kg for 100Mo
300 mBq/kg for 82Se
208Tl
: 300 mBq/kg
~ 0,2 evt kg1 y 1 with 2,8<E1+E2<3,2 MeV
  100Mo
T1/2 = 7.11 1018 y
~ 0,3 evt kg1 y 1 with 2,8<E1+E2<3,2 MeV
SuperNEMO Background requirement
Internal :
208Tl
:
214Bi :
2 mBq/kg for 82Se
10 mBq/kg
Matthias Laubenstein future measurement :
The present level of sensitivity is 1 mBq/kg (Modane Lab),
possibility of a better sensitivity on GeMPI
(a few 100 mBq/kg)
effective volume of sample chamber ~ 15 l
Challenge : from NEMO3 to SuperNEMO
NEMO3 Backgrounds
 External :
 Internal :
214Bi
negligeable
: 60 mBq/kg for 100Mo
300 mBq/kg for 82Se
208Tl
: 300 mBq/kg
~ 0,2 evt kg1 y 1 with 2,8<E1+E2<3,2 MeV
  100Mo
T1/2 = 7.11 1018 y
~ 0,3 evt kg1 y 1 with 2,8<E1+E2<3,2 MeV
SuperNEMO Background requirement
Internal :
208Tl
:
214Bi :
2 mBq/kg for 82Se
10 mBq/kg
New plans for this year : purification of enriched selenium (one kilo)
1 – purification of the second kilo of enriched selenium of ITEP,
if the second kilo of ITEP is not polluted with 106Ru
Sample
82Se
powder
(mBq/kg)
Masse
(kg)
Time
(h)
40K
60Co
137Cs
238U
235U
226Ra
228Th
228Ra
106Ru
1
300
< 14
0.8 ±
0.3
0.9 ±
0.3
90 ±
15
2.9 ±
5
< 1.5
3.7 ±
7
1.6 ±
5
24 ± 3
Radioactivity of the first kilo of enriched selenium from ITEP
2 – study of elimination of
106Ru
Kurchatov Institute, Moscow
Selenium distillation
ILIAS-JRA2
Meeting in Kurchatov Institute
November 17 -18th, 2005
Youri Gaponov, Andrey Tikhomirov, Youri
Muromkin, Serge Jullian, Dominique Lalanne
There is a Kurchatov team with the skill for distillation.
Distillation has been done successfully in the past for Cadmium but not for
Selenium.
Distillation of Selenium should be easier than Cadmium, the melting point
being lower for Selenium (200 degrees at atmospheric pressure) than for
Cadmium (320 degrees).
It can be proposed to make a distillation of natural Selenium to test the
process. But for a successful distillation, the product to be used must be
pure enough, so before distillation a chemical purification is needed.
Purification programme at Kurchatov
1. A choice of a supplier and purchasing of elemental selenium in the amount
of several kilograms (the amount will be determined more accurately later,
after the program of the distillation process development is fulfilled)
2. Incoming control of impurities (admixtures) in selenium.
3. Sampling of 1 kg of initial selenium for measurements in France.
4. Selection of a purification process, pilot plant design, program of tests.
5. Determination of a tolerated « (purified selenium) / waste » ratio.
(For distillation of an enriched product this ratio must be as large as
possible).
6. Mounting of the pilot plant.
7. Start-up of the pilot plant
8. Purification of a 1-kg sample
9. test measurements in LSM
ILIAS conclusions on production and purification issues:
1- for a mass production of hundreds of kilograms of enriched selenium,
the Krasnoyarsk facility seems to be the only one in Russia.
2- a radio-purity level of a few mBq/kg seems hopeless after the production
(even with a step of “evaporation”) for 208Tl.
3- it has to be tested a real distillation process: to be done in Kurchatov soon
3- the chemical purification of INL is better than a factor of 6, a more precise
measurement should give the real value or a lower limit. If it is reached
a factor of 100 that can be correct for SuperNEMO (according the expected
level after production in Krasnoyarsk could be of 240 mBq/kg)
Conclusions for Se82 project, second year
Done :
1- Production of enriched Selenium from ITEP:
inappropriate for SuperNEMO
2- Purification in INL : more measurements needed for the answer
New agreements for testing :
1- Production in Krasnoyarsk
2- distillation in Kurchatov