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Magnet field testing

Kevin Tilley, Paul Flower, Mark Rayner , Henry Nebrensky, 16th November

• Upstream magnets:- Dipole B1

Quadrupoles Q1-Q3

• Downstream magnets:- Dipole B2

Quadrupoles Q4-Q9

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Exptl v Theoretical Field v position (Theoretical is Tapered 0.556T model Scaled to 0.534T)

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Position relative to centre (cm)

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Experimental

Theoretical

Upstream dipole – B1 – completed tests

• Upstream dipole critical to extract

beam from synchrotron vault.

• Performed functional tests prior to

installation in July.

• Performed electrical/water tests (AN talk)

Field map & L_effectiveas expected

Central field versus current to250Amps.

Measurements agreed perfectly with tables & theory (Leff) to 250A. Not tested to full field.

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Upstream dipole – B1 – future tests

• Polarity in situ• Full B.v.I tests (into saturation)

• Determine rqd reproducibility (B/I)• Measure hysteresis • & complete standardisation if rqd.

• Scheduled for w/c 14th Jan’08

• Note, some discussion about changing pole tip of this magnet for non-tapered pole (homogeneities) – use same tests

• May monitor the field of this measurement directly during running if hysteresis significant.

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Upstream quadrupole – Q1 – completed tests

• Performed functional tests prior to

installation in July.

• Performed electrical/water tests (AN talk)

• Measured g.v.I, hysteresis• Measured (g, magnetic centre,

skew)

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Upstream quadrupole – Q1 – completed tests

• Jig allows measurement of field relative to mechanical centre & known rotation – survey references.

• Sample field along 3 lines -> extract 4 parameters, then solve for (g,magnetic centre(x,y), skew). Errors in magnetic centre ~ ±0.1mm

• no significant magnetic centre displacement

• no significant skew.

• g.v. I as expected.

• hysteresis measured at ~0.5%

•- magnet works ok.

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Upstream quadrupoles – Q1-Q3 –future tests

• Polarity in situ

• Scheduled for w/c 14th Jan’08

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Downstream dipole – B2 – future tests

• Polarity in situ• Full B.v.I tests (into saturation)

• Determine rqd reproducibility (B/I)• Measure hysteresis • & complete standardisation if rqd.

• Scheduled for w/c 9th Jan’08 or early December if services available.

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Downstream quadrupoles – Q4-Q9 – present tests

• Perform basic tests.…to qualify as early as possible if any problems exist.…

• Pole tip fields to determine ~g.v.I

• Field balance on each pole tip / colloid.

• If indications, potential to perform detailed checks with jig.

• Expected to begin this week, turnaround time <1week per magnet.

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Downstream quadrupoles – Q4-Q9 – present tests

• We have only incomplete field specifications for the Q35s!

• Detailed tests on at least two Q35s complete with mirror plates.

• Measure one magnet with each of the two coil types for reference data.

• L_effective.• Adaptor & jig -> detailed (g,magnetic

centre(x,y), skew) as before.• g.v.I

• Determine required reproducibility.• Hysteresis.• Standardisation if required.

• In ~2-3weeks

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Summary.

• Upstream magnets:-

Dipole:- performs well to 250A. Checks of full current, polarity, hysteresis in situ. w/c Jan 14th

Quadrupoles: one magnet tested – performs well. Polarity of all in situ. w/c Jan14th.

• Downstream magnets:-

Dipole:- to be tested early December or w/c Jan 9th.Quadrupoles: basic testing schedule commencing

this week. Detailed measurements on at least two of differing coil types for reference data.