basic parameters
DESCRIPTION
BASIC PARAMETERS. At ‘reference’ orbit (10 MeV?). COMBINING DIPOLE & QUAD FIELD. from experience, combining variable dipole and quadrupole field in the same magnet is difficult and expensive; - PowerPoint PPT PresentationTRANSCRIPT
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA BASIC PARAMETERS
‘BF’ magnet
‘BD’ magnet
Bend angle -0.04994 0.1995 rad
Dipole strength 1.67 E-03 6.65 E-03 Tm
B Length 0.55 0.65 m
Dipole flux density 0.0302 0.102 T
Max quad gradient 9.3 5.8 T/m
Extent of good gradient 39 + 59, - 0 mm
At ‘reference’ orbit (10 MeV?)
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA COMBINING DIPOLE & QUAD FIELD
• from experience, combining variable dipole and quadrupole field in the same magnet is difficult and expensive;
• the series of ‘allowed’ harmonics in dipoles is n = 1, 3, 5, etc; ie dipoles are quadrupoles are ‘chalk and cheese’;
• the parameters given above show that the EMMA magnets are substantially quadrupole magnets with low dipole components;
SOLUTION:
• build the EMMA magnets as pure quadrupoles;
• position them off-centre to provide the dipole component;
• when the ratio dipole/quadrupole needs to be varied, adjust the quad field and move the magnets radially to retain to correct dipole field.
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA MOVING MAGNETS DURING OPERATION
• In HERA (DESY), e- spin transfer into the longitudinal plane requires a horizontal and vertical bump to be applied after vertical polarisation has been achieved –
• horizontal is applied first;
• then the vertical bump is applied and magnet positions changed to keep beam inside the vacuum vessel.
IS NOT NEW!
With thanks to Prof. Des Barber, DESY and U. of Liverpool. – see http://www.lancs.ac.uk/cockcroft-institute/education/Barber_spin_June06.ppt
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA BEFORE AND AFTER
Before vertical bump is applied.
After vertical bump is applied.
With thanks to Prof. Des Barber, DESY and U. of Liverpool. – see http://www.lancs.ac.uk/cockcroft-institute/education/Barber_spin_June06.ppt
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA RESULTING MAGNET PARAMETERS
‘BF’ magnet
‘BD’ magnet
Inscribed radius 44 56 mm
Peak gradient 9.3 5.8 T/m
Good gradient region 39 + 59, - 0 mm
Good gradient quality 0.2% 0.2% g(x)/g(0)
Type of magnet full quad. half quad, mirror plate
Required radial movement
7 12 mm
Amp-turns/pole ( = ) 7164 7237 At
Turns/pole (I = 200 A) 36 36
Magnet thickness 55 65 mm
Limit on coil overhang 19 19 mm
Coil construction 2 layers of 18
turns, 8mm x 8mm.
Design current density 3.0 3.0 A/mm2
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA ‘BF’ MAGNET FEA GEOMETRY
One eighth cross section used for 2D f.e.a of BF magnet.
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA ‘BF’ GRADIENT QUALITY (LINEAR STEEL)
Expressed as: (dBy/dx (x,0))/By/dx (0,0);Gradient: 10.1 T./m at J = 3.2 A/mm2;Gradient quality: + 0.25% at x = 34 mm; -0.35% at x = 39 mm;Max induction in pole root: 1.24 T.
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA ‘BF’ GRADIENT QUALITY (NON-LINEAR STEEL)
Identical quality to linear steel case.
Gradient: 9.96 T;Hence, amplitude linearity: 98.6 %.
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA RESULTING ‘BF’DESIGN
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA ‘BD’ MAGNET FEA GEOMETRY
One eighth cross section used for 2D f.e.a of BD magnet; half-magnet geometry and mirror plate ignored (for the moment).
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA ‘BD’ GRADIENT QUALITY (LINEAR STEEL)
Expressed as: (dBy/dx (x,0))/By/dx (0,0);Gradient: 6.19 T/m at J = 3.2 A/mm2;Gradient quality: + 0.04% at x = 45 mm; -0.28% at x = 59 mm;Max induction in pole root: < 1.0 T.
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA HALF ‘BD’ MAGNET WITH MIRROR PLATE
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA HALF ‘BD’ GRADIENT QUALITY (LINEAR STEEL) on y = 0 axis
Expressed as: (By/dx (x,0))/By/dx (0,0); between x = 5 and x = 60;(steel at x = 0 gives singularity in dBy/dx);Gradient quality: + 0.1% at x = 55 mm; - 0.25% at x = 59 mm.
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA HALF ‘BD’ GRADIENT QUALITY (LINEAR STEEL) on x = 0 axis
Expressed as: D(Bx/dy (0,y))/Bx/dy (0,0); between y = 0 and y = 30;Gradient quality: + 0.03% at y = 30 mm;
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA RESULTING ‘BD’ DESIGN
EMMA Hardware Meeting 1/7/06Neil Marks
EMMA CELL LAYOUT GEOMETRY
NOTE MAGNET PROXIMITY
EMMA Hardware Meeting 1/7/06Neil Marks
EMMAINJECTION/EXTRACTION
PATH
Note injection line cutting through mirror plate on median plane