Paul Scherrer Institut

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21. April 2023PSI, 21. April 2023PSI,

Paul Scherrer Institut

Diamond Detectors for Transactinide Chemistry

Patrick Steinegger

Outline

• Introduction to transactinide chemistry

• The COLD thermochromatography setup and resulting deposition pattern

• Problems with common Si PIN-diodes and possible application of diamond detectors

• First trials using diamond detectors

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Transactinide Chemistry Experiments

We are interested in the chemical properties of transactinide elements ( Z > 103 ) with a special focus on the so-called superheavy elements ( SHE ).

For instance, this is achieved by deducing adsorption enthalpies (-Hads) using the thermochormatography setup with the Cryo – OnLine – Detector ( COLD ).

I. Zvara, Isotopenpraxis 26 ( 1990 ) 6, pp. 251 – 258

T = 35 °C T = -180°C

Detector array

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Schematic Experimental Setup

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[1] Y. Oganessian et al., Phys. Rev. C 70 ( 2004 )

[2] R. Eichler et al., Nature 447 ( 2007 ), pp. 72 – 75

Hg () Rn ()

Decay properties of SHE 114 (observed at FLNR in 2004 [1] )

[2]

The COLD Detector Array

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Deposition of 185Hg and 219Rn along COLD

Monte Carlo Simulation

Temperature limitation at Tmax ≈ 40 °C

Higher temperatures would enable the determination of adsorption enthalpies of elements with even higher adsorption characteristics on gold ( e.g. 113, Tl, Hg, Pb, etc. → e.g. 10 diamond sandwitch detectors in the COLD array for the „hot region“).

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Deposition of Element Cn ( 112 )

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(-5°C)

(-21°C)(-39°C) (-124°C)

(-28°C)

Further Diamond Detector Applications

Since diamond detectors can be operated near a hot source (e.g. oven), they are perfectly suitable for isothermal vacuumchormatography experiments:

DiamondDetector (cooled catcher)

Heat source (e.g. resistance oven)

Read-outElectron.

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The transition from gas chromatography towards vacuum chromatography (either isothermal or thermal) has the following advantages:

- No aerosol transport and therefore lower background (decreased random rate)- Less pollutions (organic impurities, water, etc.) → clean stationary surfaces- Better energy resolution in case of vacuum thermochromatography- Less chromatographic resolution due to random walk

The possibility of positioning the detector near an IR, UV or VIS source or the operation in the vicinity of an oven is another important feature for other experiments (thermal release expperiments → T ≈ 1200 °C).

Isothermal Vacuumchromatography

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Further Diamond Detector Applications

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Another option are online studies of electrochemically spontanous deposition of superheavy elements on metallized detector surfaces. So far, applied Si detector material was usually damaged due to electrode surface „pinholes“.

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First Trials with CVD / B-doped Diamond

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Diamond “glued” and wire-bonded onto ceramic carrier

3-line source

( 239Pu, 241Am, 244Cm )

DBS Microwave SA

First Trials with Element6 scCVD Diamond

So far it has not yet been possible to record a spectrum. We use(d) different setups - among them the one applied by Pomorski et al. [1] and again another with the diamond glued on a ceramic carrier.

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[1] M. Pomorski, Phys. Stat. Sol. (a) 203 ( 2006 ) 12, pp. 3152 – 3160

Ceramic carrier Glued diamond Wire bonding

Voltage connections

Signal out

Swan Research

10 nm Cr / 100 nm Au ( both sides)

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Thank you for your kind attention!