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Beamline Deflection of Secondary Beamline for AEgIS Collaboration Gerard Lawler Boston University CERN glawler@bu.edu May 11, 2015 Gerard Lawler Deflection of Secondary Beamline Einzel lens Beamline Subsection Example Overview Go over

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Beamline

Deflection of Secondary Beamline for AEgIS Collaboration

Gerard Lawler

Boston University CERN glawler@bu.edu

May 11, 2015

Gerard Lawler Deflection of Secondary Beamline

SLIDE 2

Beamline Einzel lens Subsection Example

Overview

Go over and explain the basic beamline elements in use (columnator, einzel lens, HV electrodes). Discuss effectiveness of each. Highlight problems which arose. Explain modifications. Cover additional and explain plans for the future.

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

Beamline

Antiproton beam I am working with is extremely wide. Degraders make things worse increasing the angular scattering. Huge number of background events (protons, pions, fragments) from annihilations in the degrader. Also, background is fast. It will saturate detector quickly.

Figure : Beam profile Figure : Total energies

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

Einzel lens

Original suggestion for first beamline element was einzel len. Consist of three electrodes in sequence. Two ends are at 0 potential and middle one is at some high potential.

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

Einzel lens

Sufficient focusing required too high voltage (≈ 105 V) More realistic, kiloVolt range einzel lens is below

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

Columnator

Intended to reject antiprotons with wilder trajectories after focsing. However, when paired with realistic voltage einzel lens. It eleminated too any antiprotons. Decided to widen aperature and place first then have to focus fewer antiprotons which would need lower voltage on lens electrode.

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

HV Electrodes

Means by which 0 to 10 keV antiprotons are selected. Began with no firm idea as to geometry. Found paper A simple double-focusing electrostatic ion beam deflector. Using and modifying some of its ideas.

Figure : From paper Figure : Own implementation

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

Beamline Idea

from 2015-05-11 12:54:04.png

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

Beamline So Far

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

Future Directions

Add second einzel lens after electrodes to refocus beam. Try to extend curvature of HV electrodes to keep beam focused. Assess power loss in accelerating beam around corner with Theorem (Larmor Formula) P =

q2a2 6πε0c3 (SI units)

Pass more antiprotons through deflector.

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

References

Angela Gligorova, Helga Holmestad, Torkjell Huse, Nicola Pacifico, Ole Rohne, Heidi Sandaker (2012) Improved setup for the secondary beam line AEgIS CM - 25.02.2015

H. Kreckel, H. Bruhns, K. A. Miller, E. Wahlin, A. Davis, S. Hckh, and D.
W. Savin (2010)

A simple double-focusing electrostatic ion beam deflector REVIEW OF SCIENTIFIC INSTRUMENTS 81, 063304 (2010) R.B. Miller (1982) An Introduction to the Physics of Intense Charged Partucle Beams Springer Plenum Presss 1982

Gerard Lawler Deflection of Secondary Beamline

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Beamline Einzel lens Subsection Example

The End

Gerard Lawler Deflection of Secondary Beamline