uk neutrino factory meeting front end test stand (f.e.t.s.) engineering status by p. savage 22nd...

UK Neutrino Factory Meeting

Front End Test Stand (F.E.T.S.)Engineering Status

by P. Savage22nd April 2009

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SourceChopperL.E.B.T. R.F.Q. Diagnostics

1.Laser Based Beam Profile Measurement Tank

2.L.E.B.T. assembly

3.R.F.Q. Concept developments

4.Pepperpot Emittance Measurement System

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1) First Tank

Laser Based Beam Profile Measurement

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Position 1 Position 2 Position 3

Laser Ion Beam

BEAM PROFILE MEASUREMENT SYSTEM

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Vacuum Linear Stage

Vacuum Rotary Stage

Mirror to deflect laser

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2 linear drives, each with an attached rotary drive mounted to a back plate in the vertical position.


CONCEPT

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Now the horizontal linear / rotary drive pairs have been added to the motor chassis


CONCEPT

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A tunnel has been placed between the horizontal drives, this volume will be pumped separately from the main vessel and will contain diagnostics.


CONCEPT

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The detector has been added to the differentially pumped tunnel.


CONCEPT

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... And the tunnel has been closed and extended with sprung ends to mate with the internal faces of the containing vessel.


CONCEPT

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BEAM PROFILE MEASUREMENT

SYSTEM

Door Chassis

Motor Chassis

CONCEPT

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Faraday cup is isolated from ground.

Thin fabricated copper jacket is at 2kV to accelerate the electrons.

100 Amp turns onto soft iron yoke.

Soft iron (permeability = 600) dipole is at ground potential.


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Motor chassis

Door chassis

Detector

Vacuum vessel


200mm

Laser in

Laser out

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Laser in

Laser out

Beam

Vacuum Pumps3 x 800 l/s

Faraday cup assembly / beam stop

Sub-D feed-through panel for linear and rotary motors

BNC feed-through flange for detector

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2) L.E.B.T.

Low Energy beam Transport

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LOW ENERGY BEAM TRANSPORT

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Solenoid

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Solenoids

Beam direction

First tankDown stream wall


L.E.B.T. support frame

Solenoid / drift vessel support bridges x4

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Drift vessel

Beam pipe sectionsFlexible bellows

Support and alignment structures x 4

Drift lengths:d1 = 25cmd2 = 13.5cmd3 = 35cmd4 = 17cm


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L.E.B.T. FARADAY CUP / BEAM STOPFaraday cup / beam stop assembly

Pneumatic linear feed-through mechanism

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An assembly of front plate (at ground) (1), secondary electron suppression ring (2) and faraday cup (3) all mounted to a cooled stainless steel welded assembly(4). The complete assembly can move downwards out of the beam path.

1 2 3 4

Toroid

Toroid casing

Mu metal shield

Beam pipe seal

Electrical feed-through x 6

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What is next for the LEBT development?

a) Install L.E.B.T. beam pipe sections and drift vessel, attach pump and conduct vacuum test.

b) Finalise design for L.E.B.T. drift vessel toroid and cooled faraday cup/beam stop assembly.

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3) R.F.Q.

Radio Frequency Quadrupole

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324 MHz Four Vane R.F.Q.

To accelerate H- beam from 65keV to 3Mev

An R.F.Q. consists of:

•Copper structure•Vacuum tight•Vane tip modulations•Cooling channels

•Tuners•RF coupling•Vacuum ports•Support / alignment structure

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PLUG TUNER

Currently working on the design of the plug tuners.

Each 1m RFQ section may have perhaps 20 static plug tuners and 1 dynamic plug tuner.

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PLUG TUNER

Cooling pipes

‘O’ ring groove

Copper plug

Stainless steel insert

Braze interfaces

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DYNAMIC PLUG TUNER ASSEMBLY

The plug tuner is mounted to a linear feed-through mechanism that maintains a vacuum seal by using an edge welded bellows. The model shown here has 50mm of travel and is driven by a stepper motor.

Stepper motor

Bellows

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PLUG TUNERS ATTACHED TO ONE RFQ SECTION

So already the basic RFQ structure becomes cluttered and this is before including provision for vacuum, RF and support / alignment.

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What is next for the RFQ development?

a) Finalise static and dynamic tuner design for the RFQ. Manufacture prototype plug assembly and send for vacuum brazing to test joint design.

b) Design in remaining RFQ features including the vacuum ports, RF coupling section and support/alignment framework.

c) Choose RFQ assembly technique and make test assemblies to check joint quality.

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4) Pepperpot

A device for measuring beam emittance

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Close up of the assembled grid head showing the quartz plate.

PEPPERPOT

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Fast CCD camera

H- beam

Exploded view of grid head

PEPPERPOT

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What is next for the Pepperpot system?

Mount the system inside a vacuum vessel that can be positioned at any longitudinal position on the FETS. In addition to pepperpot measurement the vacuum vessel will allow for slit-slit measurements.

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Goal for this year

To have a working H- beam that is transported through the first laser based diagnostic vessel, through the LEBT and then through a range of diagnostics including a toroid, a slit-slit scanner or a pepperpot head before finally hitting the beam stop.

To have a complete design for the RFQ and associated peripherals.

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THANK YOU

Any questions?

uk neutrino factory meeting front end test stand (f.e.t.s.) engineering status by p. savage 22nd...

Documents

beam profile measurement

beam profile measurementslide

beam path

h beam

drift vessel toroid

linear drives

assemblypneumatic linear

drift lengths