Outline Part 1 (SISAK system) The SISAK System (part 1) · The SISAK System (part 1) ......
Transcript of Outline Part 1 (SISAK system) The SISAK System (part 1) · The SISAK System (part 1) ......
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Jon Petter Omtvedt ASRC seminar, Tokai, 27th September 2011
The SISAK System (part 1) On-line LS Detection (part 2)
Slide 2 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Outline – Part 1 (SISAK system)
1) What is SISAK?
1) Principle
2) History and highlights
2) SISAK SHE research
a. Adoption to SHE research
b. Highlights
c. Experience gained
3) Conclusions
Slide 3 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Outline – Part 2 (LS Detection)
1) Background 1) Principle
2) History
2) On-line LS for SISAK a. Detection cells
b. PSD electronics
c. Scintillation yield monitoring
3) Conclusions
Slide 4 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Oslo Group and Collaborators
Project leader: Prof. Jon Petter Omtvedt Senior scientists: Prof. Jorolf Alstad and Prof. Tor Bjørnstad.
Post docs: Dr. Karsten Opel, Dr. Alexey Sabelnikov, Dr. Nalinava Sen Gupta.
PhDs: Marcus Johansson (2000), Liv Stavsetra (2005), Li Zheng (2007), Fereshteh Samadani (2010), Darina Polakova (on-going).
Masters: Kristin Fure (1998), Liv Stavsetra (1999), Elin A. Hult (1999), Jan-Erik Dyve (2000), Hanne Breivik (2001), Fereshteh Samadani (2006), Beyene G. Haile (2008), Frøydis Schulz (2009), Johannes Nilsen (2009).
Key collaborators: Prof. Darleane Hoffman (LBNL), Dr. Ken Gregorich (LBNL), Prof. Heino Nitsche (LBNL), Dr. Matthias Schädel (GSI), Prof. Christoph Düllmann (GSI), Prof. Gunnar Skarnemark (Chalmers), Dr. Klaus Eberhardt (U. Mainz), Dr. Norbert Trautmann (U. Mainz), Prof. Andreas Türler (PSI), Dr. Alexander Yakushev (GSI).
Many others: Students, technicians and other personnel at Oslo, LBNL, Mainz and GSI.
Part 1) What is SISAK?
a. Principle
b. History and highlights
Slide 6 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Liquid-liquid Extraction System SISAK
SISAK = Short-lived Isotopes Studied by the AKUFVE- technique
AKUFVE is a Swedish acronym for an arrangement for continuous investigations of distribution ratios in liquid-liquid extraction.
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Slide 7 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
AqAq
OrgOrg
Aq
Org
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VR
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Purpose is to measure distribution of a given species between two immiscible phases:
Liquid-liquid Extraction (LLE)
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For continuous-flow system (SISAK)
concentration is measured as activity / flow rate.
↑
Slide 8 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Liquid-liquid Extraction System
● AKUFVE ● Distribution ratios ● Continuous flow
● Fast
Slide 9 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Liquid-liquid Extraction System
● AKUFVE ● Distribution ratios ● Continuous flow
● Special centrifuges
● Fast Separation chamber
Inlet/outlets
Rotating cup
Slide 10 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Liquid-liquid Extraction System
Phase boundary
● AKUFVE ● Distribution ratios ● Continuous flow
● Special centrifuges
● Fast
Slide 11 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Liquid-liquid Extraction System
Throttles control phase separation
Phase separation monitored by measuring light transmission
Slide 12 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Liquid-liquid Extraction System
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Slide 13 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Liquid-liquid Extraction System
Centrifuge (H-10) developed in Gothenburg in the 1970s.
Application and further development by a Gothenburg-Oslo-Mainz collaboration.
Separation chamber volume reduced with each generation:
- 120 mL → 12 mL → 0.3 mL
Reinhardt & Rydberg, JActaChemScand 23 (1969) p2773. Persson et al. RCA48, (1989) p177. Commercialized by Swedish company MEAB AB.
● Three generations
● AKUFVE ● Distribution ratios ● Continuous flow
● Special centrifuges
● Fast
● Designed in 1970s
Slide 14 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Liquid-liquid Extraction System
● AKUFVE ● Distribution ratios ● Continuous flow
● Special centrifuges
● Three generations
● 0.3 mL chamber
● Fast
Standard setup with degasser and main extraction stage
● PEEK
● Two types: → liquid-liquid → gas-liquid
Omtvedt et al., J. Alloys & Comp. 271–273 (1998) p303.
Slide 15 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
History (I) ● Project initiated in 1969/70 by Janne Rydberg at Chalmers to
see if the new H-33 centrifuges could be used to study short- lived chemical states.
● Soon it was realised that the system was suitable for studying short-lived nuclei.
● In 1971 the first on-line n-irradiation, separation and γ-measurement was performed on Cu nuclei.
● The name SISAK was adopted in 1972 (Short-lived Isotopes Studied by the AKUFVE technique).
● September 1972 SISAK moves to Oslo, which has a n-generator yielding 10x more neutrons (La, Ce and Pr nuclei are investigated).
Slide 16 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
History (II) ● In 1974 a successful test is performed in Mainz. It’s the first
time a gas-jet has been successfully coupled to a chemical system.
● In 1975 the Göteborg-Mainz-Oslo collaboration is formed.
● In 1975 a new and much faster centrifuge is developed and tested, the H-10 (”SISAK 2").
● In 1975-1980 many successful experiments (La, and Ce) in Mainz are performed. Parallel to this a huge effort is done to develop chemical separation systems for Br, I, As, Tc, Ru and Pd. Experiments on Tc isotopes are started in 1979.
● In 1981 a new degasser is developed, which results in faster transport and less radiation health-hazards.
● First experiment at GSI in 1985 (on 243,244Np).
Slide 17 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
History (III) ● First experiment at GSI in 1985 (on 243,244Np).
● In 1987 it is decided that SISAK will be used for transactinide research. This demands that the waste volumes must be reduced.
● New and smaller centrifuges (”SISAK 3") are developed and built in 1988.
● 1989-1990: SISAK 3 is used to study e.g. the 0.8-s 110Tc and 0.8-s 113Ru.
● In 1994 the 0.30 s nuclei 111Tc was observed with SISAK. It’s the most short lived nuclei ever observed after separation with an aqueous based system.
Outline
a. Adoption to SHE research
b. Highlights
c. Experience gained
Part 2) SISAK SHE research
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Slide 19 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
History – SISAK and SHE ● In 1992-1994 chemical separations systems for Rf, Db and Sg
are developed. Model experiments are done at GSI and PSI with the homologes Hf, Ta and W and in Mainz with Zr, Nb and Mo.
● In parallel, a α-detection system is developed, based on liquid scintillation counting techniques.
● In 1995 the first SISAK experiment at LBNL is performed. However, the experiments fails to detect Rf and Db.
● In 1996-1997 further transactinide experiments are done at GSI (Sg), LBNL (Db) and PSI (Rf). Regretfully no transactinide activity is observed due to huge background and pile-up problems.
Slide 20 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Early SISAK Oslo-group
Jorolf Alstad, Liv Stavsetra, Kristin Fure, Elin A. Hult, Marcus Johansson, Jon Petter Omtvedt in collaboration with Mainz and Gothenburg groups
Slide 21 J.P. Omtvedt, ASRC seminar, Tokai, September 2011 Slide 22 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Basic SISAK System late 1990s
Degasser MainExtraction
Org.
Gas jet0.5-1.6 L/min
Orgainc phasereservoir(flow: 0.5-2 mL/s)
Aqueous phase reservoir(flow: 0.5-2 mL/s)
Mixer
Aq.
Pump
Pump
Phase Puritysensor
Phase Puritysensor
Pump Power Supplies(0-35 V, 1 A / pump)
Phase Purity monitor
(PC with 0-5V analog inputs)
Centrifuge Power Supply(Spintec Sf750)
Centrifuge Power Supply(Spintec Sf750)
Amplifier
Slide 23 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
248Cm(18O,5n)261Rf (78 s) → 257No (26 s)
7800 8000 8200 8400 8600 8800
7800
8000
8200
8400
8600
8800 A ll co rrela tion s
W ith in two T1/2
Mother energy (keV)
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Slide 24 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Preseparation w. RTC
Berkeley Gas-filled Seperator (BGS) ●Preseparations removes unwanted background.
●Recoil Transfer Chamber (RTC).
●Allows chemical experiment to focus on chemical properties, not separation.
●Makes α liquid-scintillation detection possible.
Developed at LBNL by Kirback & Gregorich. Kirback et al., NIM A 484 (2002) p587. Omtvedt et al., J. Nucl. RadioSci. 3 (2002) p121.
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Slide 25 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Preseparation w. RTC
Slide 26 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
New RTC: 100 x 40 mm window supported on a honeycomb grid with 80% transmission.
Old RTC: 57 x 143 mm window with 80% transmission honeycomb.
RTC windows
Slide 27 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
0 10 20 30 40 50 600
25
50
75
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197Au(
22Ne,xn)
219-xAc
207Pb(
64Ni,1n)
270110
244Pu(
48Ca,4n)
288114
248Bk(
19O,5n)
262Db
248Cm(
18O,5n)
261Rf
208Pb(
50Ti,1n)
257Rf
Recoil
ene
rgy (
MeV
)
Beam-particle mass (u)
249Cf(
12C,4n)
257Rf
RTC Window Thickness LBNL 2000: BGS - SISAK - LS-array
Slide 29 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SHE Chemistry
• Rf extracted as a DBP complex from 6 M HNO3 solution with HDBP in Toluene.
• Rf extracted with TOA from oxalic acid.
• Rf extracted with TOA from sulphuric acid.
Slide 30 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Oxalic Acid
● 0.1 M Oxalic acid.
● Rf is extracted as oxalate with tri-n-octylamine (TOA, 0.1 M) into toluene.
● This system do not need a washing step (as do the nitric- acid system).
● Reaction: 208Pb(237 MeV 50Ti12+, 1n)257Rf performed at LBNL using the BGS with RTC.
● Measured ~70% extraction for Rf, comparable to Hf.
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Slide 31 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Extraction from Sulphuric Acid
● In a work by Yagodin et al.[1] it is shown that Zr is preferentially extracted (with respect to Hf) by tri-– octylamine (TOA) from sulphate solutions.
● Results can be obtained at modest sulphate and TOA concentrations.
● Two experiments, in 2003 and 2005 (to be published).
● 2005 experiment with double detector arrays in order to measure activity in both phases simultaneously.
[1] G.A.Yagodin et al. Proc. Int. Solv. Extraction Conf. 1971 (ISEC71), the Hague, April 1971, paper 208.
Slide 32 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Rf Extracted with TOA from Sulphuric Acid
Results from LBNL 2003 & 2005 SISAK experiments
Main result
Rf seems to behave more like Hf than Zr when complexed with sulphate ligands.
This is in accordance with theoretical expectations (Pershina et al. RCA 2007).
Slide 33 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Full SISAK system for SHE
Degasser
Aq.phaseExtraction
MainExtraction
Ar flushing
Ar flushingA
q.p
ha
se
Org. phase
Gas jet
Aq. phase
Org. phase
Org.phase
Scintillator
Scintillator
Todetectors(organicphase)
Todetectors(aqueous
phase)
Added in 2005
Slide 34 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
LBNL 2005: SISAK + 2 Detector Arrays
Slide 35 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
2000 - The transactinide 257Rf detected with SISAK liquid scintillation
detectors, proved that studying SHE with SISAK is possible.
2001 - Rf extracted from 6 HNO3 into toluene with HDBP, first SISAK
chemistry experiment on a SHE.
- Rf extracted from oxalic acid into toluene with TOA.
2003 - Rf extracted from sulphuric acid into toluene with TOA.
2005 - Rf extracted from H2SO4, simultaneous detection of both
phases enhances yield and precision.
2006-7 - Knowledge from BGS-RTC used in building two RTC’s for
TASCA, one large and one small.
2008 - New small RTC built for BGS
- 258Db detected with SISAK LS-detection system.
2009 - First GSI experiment with SISAK@TASCA, testing Hs-chemistry with Os.
SISAK achievements 2000-2009 Achievements 2000-2010
Slide 36 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Important Improvements 2000
2005
Premixer
Only one throttle
Org. feed
0.7 mm (i.d.) tubes
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Slide 37 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Hassium
Reaction:
HsO4+ 2OH- ↔ *HsO4(OH)2]2-
Assumptions:
● OsO4is primarily dissolved in organic phase.
● [OsO4(OH)2]2- primarily dissolved in aqueous phase.
● Experiment performed by von Zweidorf et al., but could not distinguish between Os and Hs behaviour.
von Zweidorf et al.: Radiochim. Acta 92, 855 (2004).
Slide 38 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Equilibrium Extraction
●System for investigating Hs
●Developed with γ-emitting Os (OCL) and α-emitting Os (GSI).
Samadani, PhD thesis Univ. Oslo (2010). Samadani et al., RCA 98 (2010) p757. Samadani et al., to be submitted to RCA.
Slide 39 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Equilibrium condition → Premixer
●Phases must be mixed thoroughly enough to ensure extraction under equilibrium conditions.
●Slow kinetics will lead to severe decay loss.
●Efficient mixing very important!
Extraction of OsO4 into toluene, from Samadani et al., RCA98 (2010) (DOI 10.1524/ract.2010.1787)
Slide 40 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
Conclusions
● SISAN ability to measure 4-s 257Rf proven in many experiments and for three different chemistries.
● Likely that SISAK can also handle Db and Sg “without problem”.
● SISAK chemistry to study Hs developed.
● SISAK detector system very effective and true on-line
– can be used for other liquid-phase experiments.
Slide 41 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
SISAK Oslo Group and Collaborators
Project leader: Prof. Jon Petter Omtvedt Senior scientists: Prof. Jorolf Alstad and Prof. Tor Bjørnstad.
Post docs: Dr. Karsten Opel, Dr. Alexey Sabelnikov, Dr. Nalinava Sen Gupta.
PhDs: Marcus Johansson (2000), Liv Stavsetra (2005), Li Zheng (2007), Fereshteh Samadani (2010), Darina Polakova (on-going).
Masters: Kristin Fure (1998), Liv Stavsetra (1999), Elin A. Hult (1999), Jan-Erik Dyve (2000), Hanne Breivik (2001), Fereshteh Samadani (2006), Beyene G. Haile (2008), Frøydis Schulz (2009), Johannes Nilsen (2009).
Key collaborators: Prof. Darleane Hoffman (LBNL), Dr. Ken Gregorich (LBNL), Prof. Heino Nitsche (LBNL), Dr. Matthias Schädel (GSI), Prof. Christoph Düllmann (GSI), Prof. Gunnar Skarnemark (Chalmers), Dr. Klaus Eberhardt (U. Mainz), Dr. Norbert Trautmann (U. Mainz), Prof. Andreas Türler (PSI), Dr. Alexander Yakushev (GSI).
Many others: Students, technicians and other personnel at Oslo, LBNL, Mainz and GSI.
Slide 42 J.P. Omtvedt, ASRC seminar, Tokai, September 2011
ANNOUNCEMENT: Post. Doc. position
● 3 year post. doc. position in Oslo will be announced in a couple of weeks.
● Will be responsible for SISAK system.
● Work at OCL and within SISAK SHE collaboration.
● Can also be involved in investigating thorium (using LLE) for use as fuel in Nuclear Power Plants.
● Many exciting challenges and possibilities!
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The end (of part 1)