Outline Part 1 (SISAK system) The SISAK System (part 1) · The SISAK System (part 1) ... (18O,5n)261Rf (78 s) → 257No (26 s) 7800 8000 8200 8400 8600 8800 7800 8000 ... •Rf extracted

28.09.2011

1

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


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


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


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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AqAq

OrgOrg

Aq

Org

VR

VR

X

XD

/

/

][

][

Purpose is to measure distribution of a given species between two immiscible phases:

Liquid-liquid Extraction (LLE)

• • • •

• •

• •

• • • •

• •

• •

• •

• •

• • • •

• •

• •

• • • •

• •

• •

• •

• •

For continuous-flow system (SISAK)

concentration is measured as activity / flow rate.

↑


SISAK Liquid-liquid Extraction System

● AKUFVE ● Distribution ratios ● Continuous flow

● Fast




● Special centrifuges

● Fast Separation chamber

Inlet/outlets

Rotating cup



Phase boundary



● Fast



Throttles control phase separation

Phase separation monitored by measuring light transmission



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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



● Fast

● Designed in 1970s





● 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.


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).


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).


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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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.


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


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)

0

2

4

6

87800 8000 8200 8400 8600 8800

0 2 4 6 8

7800

8000

8200

8400

8600

8800

0 2 4 6 8 10

0

2

4

6

8

Time (T1/2

)


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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Preseparation w. RTC


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


0 10 20 30 40 50 600

25

50

75

100

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


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.


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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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.


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).


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


LBNL 2005: SISAK + 2 Detector Arrays


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


Important Improvements 2000

2005

Premixer

Only one throttle

Org. feed

0.7 mm (i.d.) tubes

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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).


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.


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)


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.


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.


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)

Documents

Outline Part 1 (SISAK system) The SISAK System (part 1) · The SISAK System (part 1) ... (18O,5n)261Rf (78 s) → 257No (26 s) 7800 8000 8200 8400 8600 8800 7800 8000 ... •Rf extracted