Task 6: Short Period Nb3Sn Superconducting Helical Undulator

Jim Clarke/George Ellwood28/11/2012

Contents• Goals• Status• Testing• Schedule

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NbTi Helical Undulator• Final Parameters:

• 215A

• Beam tube ID: 4.7 mm

• Winding ID: 6.35 mm

• Field on axis: 0.86 T

• Margin with this conductor: 30%

(Revised) Goals• To create two identical undulators with Nb3Sn

• 300mm long and direct comparison with previous NbTi undulators

• The same period, diameter, winding groove etc as NbTi

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Supercon – final wire choice

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•Field on axis 1.2T 40%> NbTi

•Operating current 720A

•Peak field on conductor 3.5T

Supercon Test Results from CERN

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• Operating current 720A required

• Wire will quench at <4T

• Not ideal but we will gain useful experience by winding an undulator with this wire

• So, we will wind two 300mm helical undulators and measure their performance in terms of quench, stability, and peak field

Alumina Coating

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50µm Alumina plasma sprayed coating.

This has been electrically tested to over 1000V without breaking down.

Heat treatment and vacuum impregnation tooling

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1st Milestone Undulator

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Now fully fabricated, wound, impregnated and heat treated – ready for tests

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Testing• No suitable test cryostat at RAL• LASA Milan (Giovanni Volpini) have kindly

offered to carry out the tests of both undulators

• Thanks to Amalia/CERN and Frank/KIT for also trying to fit us in!

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4.3mm diameter bore

Arepoc Hall probe mounted on a carbon fibre rodMaximum diameter 4mm

• Good interaction with LASA• Drawings developed• Interfaces all being considered

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Schedule• Undulator 1 ready for test now• Undulator 2 ready for test by end December• Both undulators should be tested at LASA by

mid Feb 2013.• Test one after the other ~3 days each• Simple peak B field check with Hall probe and

magnet performance as function of current

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Summary• We are still on target to achieve our goals by

the end of M48• We have completed the first undulator, fully

impregnated and heat treated• Second undulator to follow shortly• Tests will be carried out at LASA Milan

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Acknowledgements• Many thanks to our colleagues at LASA, CERN,

KIT and others within HFM without whom we would not have been able to achieve our goals

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