Target tests1st – 2nd Nov.

Chris Booth

Sheffield

7th December 2006

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• MICE beam pipe installed in ISIS, pumped down

• Target drive on support frame connected above gate valve

• Cables & optical fibres laid between MICE hall & ISIS vault

• Control electronics installed in MICE hall

• Power electronics installed in ISIS vault

• Scintillators installed by wall of ISIS vault– 10 m from target, at correct production angle

Installation late October

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Beam pipe and target stand

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Target drive in placePhotos

courtesy of Chris

Nelson & Paul

Drumm!

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Target drive in place

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Shielded RAL scintillation counters

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MICE hall - data taking in progress!

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• ISIS signals:

– Machine Start (MS) synchronisation signals

– Beam loss monitors

• Two RAL scintillators, in shielded box

• Two small Glasgow scintillators

• Target position readout

All digitised on scopes and read out by PC.

Instrumentation

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• Several mono-mode fibres damaged during installation, 2 beyond use

– No replacement in Europe!

– Specialist company located to repair & reinstall

• 3-channel semiconductor laser stopped working– Revived 4 days later when rep. arrived with spare!

– (but another channel later stopped for several hours)

• No motor drive for jacking mechanism– Required accesses to operate by hand, at start & end of shifts

• Problem with limit switches prevented gate-valve operation

– Fixed during access

Problems!!

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• Target drive electronics only 10 A max.– Only capable of modest accelerations

• ISIS running at 50 Hz 64

– Pulse every 1.28 s

• Survey run on night of 1st Nov.

– No signals into DAQ(!!). (Phone calls to control room!)

• Full run on night of 2nd Nov.

• Two target modes:

– Held static at various depths (to find beam size at injection)

– Maximum amplitude pulses, initially late then timing advanced to meet beam

Tests

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• Still very preliminary– Analysis of scintillator data continuing in Glasgow & RAL

– Beam loss studies in Sheffield

• “On-line” conclusions:– Beam is much smaller at injection than expected! (Does not “nearly

fill the pipe”)

– It has a hard edge

• Present state of analysis – from beam loss (see plots)– Acceleration of target only just adequate to sample beam at extraction

– Beam (halo) reaches maximum size ~2 ms after injection

– With optimum timing, target just scraped the shrinking beam through the ISIS cycle

– Beam shrinkage is ~16 mm

Results

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Beam loss versus position

Inje

ctio

n

Ext

ract

ion

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Beam loss versus position

Losses after ~2 ms Losses at

extraction

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Loss versus time and depth

Edge of pipe

Combined data – many run conditions

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• Still very preliminary– Analysis of scintillator data continuing in Glasgow & RAL

– Beam loss studies in Sheffield

• “On-line” conclusions:– Beam is much smaller at injection than expected! (Does not “nearly

fill the pipe”)

– It has a hard edge

• Present state of analysis (see plots)– Acceleration of target only just adequate to sample beam at extraction

– Beam (halo) reaches maximum size ~2 ms after injection

– With optimum timing, target just scraped the shrinking beam through the ISIS cycle

– Beam shrinkage is ~16 mm

Results

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• Drive remains in ISIS (electronics back in Sheffield)

• Old target drive recommissioned (with new optical readout) in Sheffield

• New drive electronics from Daresbury last week– Some problems, to be sorted

– Higher current, but significant voltage droop through the pulse

• Tuning of control electronics in progress– Higher accelerations seen

– Some reliability problems (due to droop?)

• Possibility of further run at end of ISIS period (week before Christmas)

• With higher acceleration, hope to clip beam at extraction only

Next steps

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• Tests were difficult, but successful

• Major effort by Sheffield, RAL, Glasgow(Thanks to all involved!)

• Much analysis still to do

• We hope we can obtain even more information in 2 weeks

Conclusions