(The Future of) SHE Chemistry with SISAK · 2000 - 257The transactinide Rf detected with SISAK liquid scintillation detectors, proved that studying SHE with SISAK is possible. 2001

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Presented at PacifiChem 2010 by

Jon Petter Omtvedt Honolulu, December 2010.

(The Future of)

SHE Chemistry with SISAK

Slide 2 J.P. Omtvedt, PacifiChem 2010, Honolulu, December 2010

Outline

● What is SISAK?

● 10 years of SISAK SHE research ● Summary of results

● Experience gained

● The (SISAK) future... ● Capabilities

● Requirements

● Organisation and Logistics

● Conclusions

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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), Dr. Christoph Düllmann (GSI), Prof. Gunnar Skarnemark (Chalmers), Dr. Klaus Eberhardt (U. Mainz), Dr. Norbert Trautmann (U. Mainz).

Many others: Students, technicians and other personnel at Oslo, LBNL, Mainz and GSI.


Outline

● What is SISAK?




● Requirements


● Conclusions

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Slide 5

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.

Slide 6

SISAK Liquid-liquid Extraction System

● AKUFVE ● Distribution ratios ● Continuous flow

● Fast

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Slide 7



● Special centrifuges

● Fast Separation chamber

Inlet/outlets

Rotating cup

Slide 8




● Fast Phase boundary

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Slide 9



● Special centrifuges 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

● 0.3 mL chamber

● Fast

Slide 10





● 0.3 mL chamber

● Fast

PEEK centrifuges developed in Oslo for SHE chemistry studies in the 1990s

● PEEK

● Two types: → liquid-liquid → gas-liquid

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Slide 11





● 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 12

On-line Liquid Scintillation α-detection

Outlet

Inlet

Light guide

PMT

Scintillationchamber

150 200 250 300 350 4000

200

400

600

800

1000

Co

un

ts/c

han

nel

Channel

219Rn,6.82 MeV

+6.55 MeV

215Po,7.39 MeV Wierczinski et al., NIM A 370 (1996) p532.

Wierczinski et al., Radioan. Nucl. Ch. 247 (2001) p57. Stavsetra & Omtvedt, Radiocarbon (2002) p24. Stavsetra, Hult & Omtvedt, NIM A 551 (2005) p323. Stavsetra et al., NIM A 543, (2005) p509.

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Slide 13

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.

Slide 14

Full SISAK system for SHE

Degasser

Aq.phaseExtraction

MainExtraction

Ar flushing

Ar flushing

Aq

.ph

ase

Org. phase

Gas jet

Aq. phase

Org. phase

Org.phase

Scintillator

Scintillator

Todetectors(organicphase)

Todetectors(aqueous

phase)

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Slide 15

Full SISAK system for SHE


Outline

● What is SISAK?




● Requirements


● Conclusions

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Slide 17

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

Results of a Oslo-LBNL-Gothenburg-Mainz collaboration

Achievements 2000-2010

Slide 18

Important Improvements 2000

2005

Premixer

Only one throttle

Org. feed

0.7 mm (i.d.) tubes

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Slide 19

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 20

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.

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Outline

● What is SISAK?




● Requirements


● Conclusions

Slide 22

The Future?

● Good chemistry cases:

- Take full advantage of the freedom offered by preseparation.

- Must be interesting for theoreticians.

- Must be clearly understood (equations known).

- Fast kinetics.

● Reliability and ease of operation.

- Less maintenance and fewer break-downs.

- Replace degassers with membrane separation units.

● Logistics and man-power

- Need collaboration with an accelerator lab with a local SISAK group/students or at least liquid-phase chemistry group.

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Slide 23

Prototype Membrane Degasser

●Teflon membrane with 0.25-1.0 μm pore size.

●Phase separation adjusted with throttle on liquid outlet.

MSc thesis work of J. Nilssen (2009).

Slide 24

Prototype Membrane Degasser (MDG)

●Teflon membrane with 0.25-1.0 μm pore size.

●Phase separation adjusted with throttle on liquid outlet.

●Tested with - 0.2-0.9 Bar suction Flow decrease

from 0.37 to 0.09 mL/s severely

reduces the gas to liquid transfer.

Unexpectedly much better

than centrifuge degasser (fitted

with mixer)!

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Slide 25

Prototype MDG with premixer

●A mixer in front of the degasser increases transfer.

- But will also slow down transport.

●Many different mixers developed through the years

- Zigzag pattern & - PEEK wool the most effective.

Slide 26

Prototype Membrane Degasser (MDG)

Fitting a mixer to MDG did not help, but was

only tested with 1 μm membane.

●A mixer in front of the degasser increases transfer.

- But will also slow down transport.

●Many different mixers developed through the years

- Zigzag pattern & - PEEK wool the most effective.

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Slide 27

Full SISAK with MDGs…

Degasser

Aq.phaseExtraction

MainExtraction

Ar flushing

Ar flushing

Aq

.ph

ase

Org. phase

Gas jet

Aq. phase

Org. phase

Org.phase

Scintillator

Scintillator

Todetectors(organicphase)

Todetectors(aqueous

phase)

●Reduction from five to two centrifuges.

Slide 28

Cryptans

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Slide 29

How Heavy SHE can SISAK handle?

SHE experiments with rutherfordium not regarded as particularly difficult anymore. SISAK has only done chemistry experiments with rutherfordium….

But:

“Normal” experiments used 1-min 261Rf, SISAK used 4-s 257Rf....

No other liquid phase chemistry has tackled 4-s SHE. For SISAK, the difference between Rf, Db, Sg, Bh and Hs is about cross-section and decay pattern, not half life.


Conclusions

● SISAK can handle Rf, Db, Sg without problem.

● SISAK might handle Bh and Hs.

● A stable, two-person per shift system can be built

– no new science, just technology.

● To justify the investment a (very) good chemistry case must be identified

– close collaboration with theorists necessary.

● Dedicated effort at one lab necessary

– will most likely require local SISAK group.

● SISAK detector system very effective and true on-line

– can be used for other liquid phase experiments.

● Funding a major issue, as always.

Documents

(The Future of) SHE Chemistry with SISAK · 2000 - 257The transactinide Rf detected with SISAK liquid scintillation detectors, proved that studying SHE with SISAK is possible. 2001