A3: DESIREE

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A3: DESIREE Design and examples of planned experiments Belfast, July 1, 2003 Henning Schmidt, Stockholm University (Double ElectroStatic Ion Ring ExpEriment)

description

Belfast, July 1, 2003. A3: DESIREE. ( D ouble E lectro S tatic I on R ing E xp E riment). Design and examples of planned experiments. Henning Schmidt, Stockholm University. Stockholm Low-Energy facilities:. DESIREE Double ElectroStatic Ion Ring ExpEriment . - PowerPoint PPT Presentation

Transcript of A3: DESIREE

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A3: DESIREE

Designand examples of planned experiments

Belfast, July 1, 2003

Henning Schmidt, Stockholm University

(Double ElectroStatic Ion Ring ExpEriment)

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Stockholm Low-Energy facilities:

DESIREEDouble ElectroStatic Ion Ring ExpEriment.

CRYSIS (EBIS source for very high charge states e.g. U70+)

ECR ion source for intense beams of moderately high charge states.

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Outline

The DESIREE project Motivation: Mutual Neutralization Brief technical description Planned experiments

AMO Physics• Example: Diffuse interstellar absorption

bandsBiomolecules

• Example: ‘Electron Capture Dissociation’

Summary

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Plasma environments:Plasma environments:The degree of ionization is a The degree of ionization is a

determining factor for the ongoing determining factor for the ongoing chemistry. chemistry. Processes that affect this parameter Processes that affect this parameter are therefore crucial.are therefore crucial.

Electron-Ion recombination:Electron-Ion recombination: XX+ + + e+ e- - X + h X + h (atomic recombination) (atomic recombination)

ABAB+ + + e+ e- - A + B (dissociative A + B (dissociative recombination)recombination)

Mutual Neutralization :Mutual Neutralization : XX++ + Y + Y-- X + Y X + Y

AA-- + BC + BC++ A + BC or A + B + C A + BC or A + B + C

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DESIREEDESIREEDDouble ouble EElectro-lectro-SStatic tatic IIon on RRing ing EExpxpEErimentriment

1 m

Double-walled vacuum vesselDouble-walled vacuum vessel Outer tank 300K - Inner tank 15KOuter tank 300K - Inner tank 15K Cooling by cryogeneratorsCooling by cryogenerators

Expected vacuum in inner Expected vacuum in inner partpart 300 K: <10300 K: <10-11-11 mbar mbar 15 K: Density reduced by order(s) 15 K: Density reduced by order(s)

of magnitudeof magnitude

Ion sources:Plasma Ion SourcesSputter Source (Negative Ions)ESI Source (Biomolecules)ECRIS (Highly Charged Ions)

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1 m

Position-sensitive detector

ELISA

DESIREE

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Merged-beams experiments

Longitudinally: Kinematical compression Transversely: Ion optics determines: < 1 eV seems feasible. Can beam cooling be developed?

Relative velocity definition:

Example: MN H-+H2+

E=10 keV/amu, Erel=1 eV, Amax=1 cm2,=1.6.10-14cm2 (COB), I+=I-=100 nA, L=80 cm: 44 s-1

Background rate is similar - The key point is that in MN there are (at least) two neutrals in coincidence!!

How about experiments with Biomolecules?

Count Rate estimates:

RN: In above example N=4.106. Feasible for ESI with trap

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Three special features of DESIREE:

Double-ring structure: Merged beams positive/negative ion collisions.

Cryogenic system: Extremely good vacuum Long storage

lifetime. Internally cold molecular ions.

Electrostatic confinement: High mass-to-charge ratios (i.e. Biomolecules). Absence of magnetic-field mixing in lifetime

measurements

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Examples of proposed experiments at the DESIREE facility:

Atoms and ‘Small’ Molecules: Single-Ring Experiments

Lifetime measurements of metastable ions (He-, C60q+,…)

LASER spectroscopy of atomic/molecular ions (e.g. Cn-)

Merged-Beams ExperimentsMutual Neutralization Collisions

• Fundamental systems (e.g. H-+H2+ …..)

• Astrophysical plasmas (e.g. Cn-+H3

+, H3O+,….)

• Atmospherical ion chemistry.

Collisions involving fullerenes(C60

q++C60-, Ar8++C60

-,….)

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Biomolecules: Single-Ring Experiments (already pursued at ELISA)

Lifetime and stability(J.U.Andersen et al, to be published)

LASER spectroscopy(e.g. GFP: S.B.Nielsen et al PRL 87, 228102 (2001))

Merged-Beams ExperimentsElectron Capture Dissociation in Negative/Positive ion

collisionsCoulombic explosions induced by highly charged ions

Biomolecules:

Examples of proposed experiments at the DESIREE facility:

Biomolecules: Single-Ring Experiments (already pursued at

ELISA)Lifetime and stability

(J.U.Andersen et al, to be published)LASER spectroscopy

(e.g. GFP: S.B.Nielsen et al PRL 87, 228102 (2001))

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Electron Capture Dissociation

ECD is important in protein sequencing because it breaks other bonds than those accessed in collision-induced dissociation.

ECD is studied by introducing electrons in the plasma of FT-ICR mass spectrometer. No control of electron impact energy.

Using simple negative ion to carry the electron, low (even below zero) and well-controlled relative energy is obtained.

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Electron-transfer

10 a0

10 a0

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Area of impact for ’distant’ collisions.

Experimental indication of distant collision: Detection of neutral

at proper time in relation to the arrival of the biomolecule(ar fragments)

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Summary:

DESIREE can be built!We can do new AMO physics in single-ring

and particularly in merged-beams configuration (Mutual Neutralization)

Spectroscopy and lifetime measurements for biomolecular ions - ELISA

’ECD’ like processes and HCI-biomolecular ion interaction in merged-beams - DESIREE unique

The End!

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DESIREE People:

Primary investigator: Ö. SkeppstedtDesign group:

K-G Rensfelt, M. Andersson, L. Bagge,H. Danared, J. Jensen, L. Liljeby, H.T. Schmidt, K. Schmidt, A. Simonsson

Contributors to the Scientific Programme:H. T. Schmidt, H. Cederquist, T. Hansson,J. Jensen, M. Larsson, S. Mannervik,P. vd Meulen, J. Pettersson. P. Royen,E. Uggerud, R. A. Zubarev

New Leif?New Life!