Artwork: A. Duncan Compact and Low Consumption Magnet Design for Future Linear and Circular...
28
ZEPTO: Tunable Permanent Magnet Dipoles and Quadrupoles Ben Shepherd, Jim Clarke, Norbert Collomb, Neil Marks STFC Daresbury Laboratory, UK Artwork: A. Duncan Michele Modena, Mike Struik, Carlo Petrone CERN, Geneva, Switzerland Compact and Low Consumption Magnet Design for Future Linear and Circular Colliders CERN, 26-28 November 2014
Artwork: A. Duncan Compact and Low Consumption Magnet Design for Future Linear and Circular Colliders CERN, 26-28 November 2014
The CLIC Drive Beam The drive beam decelerates from 2.4 GeV to
0.24 GeV transferring energy to the main beam As the electrons
decelerate, quadrupoles are needed every 1m to keep the beam
focused The quadrupole strengths scale with the beam energy The
CLIC accelerator length is ~42km so there are ~42,000 quadrupoles
needed Overview Introduction Q1 Q2 D1 Summary Ben Shepherd Compact
& Low Consumption Magnet Design Workshop CERN, 26-28 Nov
2014
Slide 4
Quadrupole Tunability The nominal maximum integrated gradient
is 12.2T and the minimum is 1.22T For operational flexibility each
individual quadrupole must operate over a wide tuning range 70% to
120% at high energy (2.4 GeV) 7% to 40% at low energy (0.24 GeV)
12.2 T 1.22 T Overview Introduction Q1 Q2 D1 Summary Ben Shepherd
Compact & Low Consumption Magnet Design Workshop CERN, 26-28
Nov 2014
Slide 5
Quadrupole Specification ParameterHigh-energy endLow-energy
endUnits Number of quadrupoles41400 Strength12.21.22T Stability5x10
-4 Integrated gradient quality0.1% Good field region11.5mm Minimum
bore radius13mm Maximum width390mm Maximum height390mm Maximum
length270mm Overview Introduction Q1 Q2 D1 Summary Ben Shepherd
Compact & Low Consumption Magnet Design Workshop CERN, 26-28
Nov 2014
Slide 6
Permanent Magnet Option The integrated magnet strength
requirement is very challenging (given the space constraints) for a
conventional electromagnet The nominal power consumption for the EM
version will be ~8 MW in nominal mode and up to ~17 MW in tune-up
mode Total Power Load limit to air within the tunnel is only 150
W/m (all components) A PM quad would potentially have many
advantages Vastly reduced electrical power Very low operating costs
No cooling water needs Very low power to air We have been
investigating the PM option for the drive beam CERN-STFC
collaboration: ZEPTO Zero-Power Tunable Optics Overview
Introduction Q1 Q2 D1 Summary Ben Shepherd Compact & Low
Consumption Magnet Design Workshop CERN, 26-28 Nov 2014
Slide 7
Permanent Magnet Challenges There are many existing PM
quadrupole examples The combination of high strength, large
tunability, high field quality, and restricted volume meant that a
new design was required Additional challenges for PM include
possible radiation damage, field variation with temperature, PM
strength variation from block to block (material and engineering
tolerances) The complete tuning range (120% to 7%) could not be met
by a single design We have broken the problem down into two magnet
designs one high energy and one low energy Overview Introduction Q1
Q2 D1 Summary Ben Shepherd Compact & Low Consumption Magnet
Design Workshop CERN, 26-28 Nov 2014
Slide 8
Quadrupole Types High energy quad Gradient very high Low energy
quad Very large tuning range Erik Adli & Daniel Siemaszko Low
Energy Quad High Energy Quad Overview Introduction Q1 Q2 D1 Summary
Ben Shepherd Compact & Low Consumption Magnet Design Workshop
CERN, 26-28 Nov 2014
Slide 9
NdFeB magnets with B r = 1.37 T (VACODYM 764 TP) 4 permanent
magnet blocks each 18 x 100 x 230 mm Mounted at optimum angle of 40
Max gradient = 60.4 T/m (stroke = 0 mm) Min gradient = 15.0 T/m
(stroke = 64 mm) Pole gap = 27.2 mm Field quality = 0.1% over 23 mm
Stroke = 64 mm Poles are permanently fixed in place High Energy
Quad Design Stroke = 0 mm Overview Introduction Q1 Q2 D1 Summary
Ben Shepherd Compact & Low Consumption Magnet Design Workshop
CERN, 26-28 Nov 2014
Slide 10
High Energy Quad Animation Overview Introduction Q1 Q2 D1
Summary Ben Shepherd Compact & Low Consumption Magnet Design
Workshop CERN, 26-28 Nov 2014
Slide 11
Engineering of High Energy Quad Single axis motion with one
motor and two ballscrews Rotary encoder on motor (linear encoders
used during setup to check repeatability) Maximum force is 16.4 kN
per side, reduces by x10 when stroke = 64 mm PM blocks bonded to
steel bridge piece and protective steel plate also bonded Steel
straps added as extra security Overview Introduction Q1 Q2 D1
Summary Ben Shepherd Compact & Low Consumption Magnet Design
Workshop CERN, 26-28 Nov 2014
Magnet Centre Movement The magnet centre moves upwards by ~100
m as the permanent magnets are moved away 3D modelling suggests
this is due to the rails being ferromagnetic ( r ~ 100, measured)
and not mounted symmetrically about the midplane should be easy to
fix Motor/gearbox assembly may also be a contributing factor
Overview Introduction Q1 Q2 D1 Summary Ben Shepherd Compact &
Low Consumption Magnet Design Workshop CERN, 26-28 Nov 2014
Slide 15
Low Energy Quad Design Lower strength easier but requires much
larger tunability range (x12) Outer shell short circuits magnetic
flux to reduce quad strength rapidly NdFeB magnets with B r = 1.37
T (VACODYM 764 TP) 2 permanent magnet blocks are 37.2 x 70 x 190 mm
Max gradient = 43.4 T/m (stroke = 0 mm) Min gradient = 3.5 T/m
(stroke = 75 mm) Pole gap = 27.6 mm Field quality = 0.1% over 23 mm
Stroke = 0 mm Stroke = 75 mm Poles and outer shell are permanently
fixed in place. Overview Introduction Q1 Q2 D1 Summary Ben Shepherd
Compact & Low Consumption Magnet Design Workshop CERN, 26-28
Nov 2014
Slide 16
Low Energy Quad Animation Overview Introduction Q1 Q2 D1
Summary Ben Shepherd Compact & Low Consumption Magnet Design
Workshop CERN, 26-28 Nov 2014
Slide 17
Engineering of Low Energy Quad Simplified single axis motion
with one motor and one ballscrew Rotary encoder on motor linear
encoders used during setup to check repeatability Maximum force is
only 0.7 kN per side PM blocks bonded within aluminium support
frame Overview Introduction Q1 Q2 D1 Summary Ben Shepherd Compact
& Low Consumption Magnet Design Workshop CERN, 26-28 Nov
2014
Slide 18
Assembled at Daresbury during 2013 Careful attention paid to
pole positions Measurements Early 2014: Hall probe at Daresbury
Late 2014: stretched wire, rotating coil at CERN Overview
Introduction Q1 Q2 D1 Summary Ben Shepherd Compact & Low
Consumption Magnet Design Workshop CERN, 26-28 Nov 2014
Slide 19
Measured Integrated Gradient Overview Introduction Q1 Q2 D1
Summary Ben Shepherd Compact & Low Consumption Magnet Design
Workshop CERN, 26-28 Nov 2014 Higher than expected tuning range!
Maximum gradient: 45.0 T/m Minimum gradient: 3.6 T/m
Slide 20
Measured Axis Movement Good agreement between measurement
methods stretched wire rotating coil X axis moves in one direction
Possible misalignment of outer shell? Y axis moves up and then back
down Harder to explain this X (horiz) Y (vert) Overview
Introduction Q1 Q2 D1 Summary Ben Shepherd Compact & Low
Consumption Magnet Design Workshop CERN, 26-28 Nov 2014
Slide 21
PM dipoles: ZEPTO-D1 New STFC-CERN work package: investigate PM
dipoles Drive Beam Turn Around Loop (DB TAL) Main Beam Ring to Main
Linac (MB RTML) Total power consumed by both types: 15 MW
Reduced-length DB TAL prototype to be constructed by Dec 2015
Several possible designs currently on the table TypeQuantityLength
(m) Strength (T) Pole Gap (mm) Good Field Region (mm) Field Quality
Range (%) MB RTML6662.00.53020 x 201 x 10 -4 10 DB TAL5761.51.65340
x 401 x 10 -4 50100 Overview Introduction Q1 Q2 D1 Summary Ben
Shepherd Compact & Low Consumption Magnet Design Workshop CERN,
26-28 Nov 2014
Slide 22
Design Concept #1 Design used for a prototype at SPring-8*
Steel top plate moves down to shunt flux from PMs and decrease
field Tuning range: 0.77-1.59T *IPAC 2014 TUPRO092, Watanabe et al
160mm max 1.8T max 2.1T 5mm Overview Introduction Q1 Q2 D1 Summary
Ben Shepherd Compact & Low Consumption Magnet Design Workshop
CERN, 26-28 Nov 2014
Slide 23
Design Concept #2 Overview Introduction Q1 Q2 D1 Summary Ben
Shepherd Compact & Low Consumption Magnet Design Workshop CERN,
26-28 Nov 2014 Moving section in backleg flux shunted between poles
Tuning range: 0.8-1.6T
Slide 24
Design Concept #3 (Neil Marks) Overview Introduction Q1 Q2 D1
Summary Ben Shepherd Compact & Low Consumption Magnet Design
Workshop CERN, 26-28 Nov 2014 Rotating cylinder in backleg (steel
and PM) Rotate by 180 to get full range Tuning range: 0.78-1.69T
Field quality (2D): 1.2x10 -4 Modelled as H-magnet (left) or
C-magnet (right)
Slide 25
Summary PM driven quads have many advantages in terms of
operating costs, infrastructure requirements, and power load in the
tunnel We have shown that only two PM designs are required to cover
the entire range of gradients required for the CLIC Drive Beam Two
prototypes have been built and measured, demonstrating the required
gradient range The magnetic centre moves vertically as the gradient
is adjusted We think we understand the reasons for this Modelling
of dipole concepts for the DB-TAL is in progress Overview
Introduction Q1 Q2 D1 Summary Ben Shepherd Compact & Low
Consumption Magnet Design Workshop CERN, 26-28 Nov 2014
Slide 26
Acknowledgments Daresbury Laboratory team Magnet design: Ben
Shepherd, Jim Clarke, Neil Marks Mechanical design: Norbert
Collomb, James Richmond, Graham Stokes CERN team Project lead:
Michele Modena Magnet measurements: Antonio Bartalesi, Mike Struik,
Marco Buzio, Samira Kasaei, Carlo Petrone Also starring: Alexandre
Samochkine, Dmitry Gudkov, Evgeny Solodko, Alexander Aloev, Alexey
Vorozhtsov, Guido Sterbini Overview Introduction Q1 Q2 D1 Summary
Ben Shepherd Compact & Low Consumption Magnet Design Workshop
CERN, 26-28 Nov 2014
Slide 27
References 1.Aicheler et al, Eds., A Multi-TeV linear collider
based on CLIC technology: CLIC Conceptual Design Report. CERN,
2012.CLIC Conceptual Design Report 2.Volk et al, Adjustable
permanent quadrupoles for the Next Linear Collider, PACS2001 Proc.
2001 PAC Cat No01CH37268, vol. 1, 2002.Adjustable permanent
quadrupoles for the Next Linear Collider 3.Tommasini et al, Design,
Manufacture and Measurements of Permanent Quadrupole Magnets for
Linac4, IEEE Trans. Appl. Supercond., vol. 22, no. 3, pp.
40007044000704, Jun. 2012.Design, Manufacture and Measurements of
Permanent Quadrupole Magnets for Linac4 4.Plostinar et al, A hybrid
quadrupole design for the RAL Front End Test Stand (FETS), in Proc.
of EPAC, 2008, vol. 8.A hybrid quadrupole design for the RAL Front
End Test Stand (FETS) 5.Lim et al, Adjustable, short focal length
permanent-magnet quadrupole based electron beam final focus system,
Phys. Rev. Spec. Top. - Accel. Beams, vol. 8, no. 7, p. 072401,
Jul. 2005.Adjustable, short focal length permanent-magnet
quadrupole based electron beam final focus system 6.Mihara et al,
Variable Permanent Magnet Quadrupole, IEEE Trans. Appl. Supercond.,
vol. 16, 2006.Variable Permanent Magnet Quadrupole 7.Iwashita et
al, Permanent Magnet Final Focus Doublet R&D for ILC at ATF2,
PAC 2009 MO6PFP024.Permanent Magnet Final Focus Doublet R&D for
ILC at ATF2 8.S. C. Gottschalk et al, Performance of an Adjustable
Strength Permanent Magnet Quadrupole, PAC 2005.Performance of an
Adjustable Strength Permanent Magnet Quadrupole 9.Clarke et al,
Novel Tunable Permanent Magnet Quadrupoles for the CLIC Drive Beam,
IEEE Trans. Appl. Supercond., vol. 24, no. 3, pp. 15, Jun.
2014.Novel Tunable Permanent Magnet Quadrupoles for the CLIC Drive
Beam 10.Shepherd, Collomb, and Clarke, Permanent magnet quadrupoles
for the CLIC Drive Beam decelerator, CLIC-Note- 940, 2012.Permanent
magnet quadrupoles for the CLIC Drive Beam decelerator
11.Bartalesi, Modena, and Struik, Results of the first measuring
campaign of the Daresbury Permanent Magnet High Gradient Quadrupole
Prototype for the CLIC Drive Beam, TE-MSC Internal Note 2013-10,
2013.Results of the first measuring campaign of the Daresbury
Permanent Magnet High Gradient Quadrupole Prototype for the CLIC
Drive Beam 12.Shepherd et al, Prototype Adjustable Permanent Magnet
Quadrupoles For CLIC, IPAC 2013 THMPE043.Prototype Adjustable
Permanent Magnet Quadrupoles For CLIC 13.Shepherd et al, Design And
Measurement Of A Low-Energy Tunable Permanent Magnet Quadrupole
Prototype, IPAC 2014 TUPRO113.Design And Measurement Of A
Low-Energy Tunable Permanent Magnet Quadrupole Prototype
14.Shepherd et al, "Tunable high-gradient permanent magnet
quadrupoles," 2014 JINST 9 T11006 doi:10.1088/1748-
0221/9/11/T11006.Tunable high-gradient permanent magnet
quadrupolesdoi:10.1088/1748- 0221/9/11/T11006 Overview Introduction
Q1 Q2 D1 Summary Ben Shepherd Compact & Low Consumption Magnet
Design Workshop CERN, 26-28 Nov 2014