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Task 2.3 - particle simulations studies: preliminary results of

D2 field quality

M. Giovannozzi

• Setting up of simulations • Results• Outlook

NB: numerical simulations performed by Y. Nosochkov et al.

WP2 TLM - 2.3 - MG27/08/2013

Setting up of simulations - I• Usual goal:

– Check the impact of the FQ estimated for the new D2 magnet on DA.

– Perform scan over multipoles aiming at making the impact of D2 FQ in the shadow of the one of the IT, i.e., DA drop of few percent.

• Conditions:– Collision configuration (round optics, 15 cm b*)– IT FQ included as specified.– D2 FQ included as specified by E. Todesco. In the

following the multipoles are relative to the official values.– Measured FQ in the rest of the machine.– Feed down from orbit in separation dipoles not included.

27/08/2013WP2 TLM - 2.3 - MG

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Setting up of simulations - II• Usual goal:

– Check the impact of the FQ estimated for the new D2 magnet on DA.

– Perform scan over multipoles aiming at making the impact of D2 FQ in the shadow of the one of the IT, i.e., DA drop of few percent.

• Conditions:– Collision configuration (round optics, 15 cm b*)– IT FQ included as specified.– D2 FQ included as specified by E. Todesco. In the

following the multipoles are specified relative to the official values.

– Measured FQ in the rest of the machine.

27/08/2013WP2 TLM - 2.3 - MG

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Results - I• Summary table

• The factor 1/4 in the multipoles corresponds to:– Reduced field (10 m magnet)– Reduced aperture (95 mm)

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label DAmin DAave IT D1 D2 Q4 Q5 adjustments000 10.10 13.37 v65* off off off off005 9.94 11.93 v65* v1 off off off

017 6.48 7.58 v65* v1 v3 v1 v0D2 scaling: b2 *0; b3 *1/4; b4 *1/4

018 6.76 7.60 v65* v1 v3 v1 v0D2 scaling: b2 *0; b3 *1/4; b4 *1/4; a2 *0

028 8.63 9.85 v65* v1 v3 v1 v0 D2 scaling: b2 *0; b3 *0; b4 *1/4029 6.69 8.25 v65* v1 v3 v1 v0 D2 scaling: b2 *0; b3 *1/4; b4 *0030 9.93 12.21 v65* v1 v3 v1 v0 D2 scaling: b2 *0; b3 *0; b4 *0

032 9.86 12.03 v65* v1 v3 v1 v0D2 scaling: b2 *0; b3 *1/4; b4 *0; tune = 62.30/60.31

038 9.44 10.51 v65* v1 v3 v1 v0D2 scaling: b2 *0; b3 *1/4; b4 *1/4; tune = 62.30/60.31

Courtesy Y. Nosochkov

Results - II

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6.0

7.0

8.0

9.0

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12.0

13.0

DA (s

igm

a)

b2, b3, b4 in D2 (normalized to "D2_errortable_v3")

SLHCV3.1b with field errors from "IT_errortable_v65", "D1_errortable_v1", "D2_errortable_v3", "Q4_errortable_v1" and "Q5_errortable_v0"

DAmin

DAave

b2 @ 1/4b3 @ 1/4b4 @ 1/4

b2 = 0b3 @ 1/4b4 @ 1/4

b2 = 0b3 @ 1/4b4 = 0

b2 = 0b3 = 0b4 @ 1/4

b2 = 0b3 = 0b4 = 0

b2 @ 1/4b3 = 0b4 @ 1/4

Courtesy Y. Nosochkov

Non-zero b2 seems to improve DA! To be checked

Outlook

• Found strong impact of the D2 FQ on DA, even for the most optimistic case, i.e., 10 m long magnet with reduced aperture.

• b3 and b4 are the most dangerous multipoles: scans will be performed to set upper bounds.

• Change of tune tested and found to improve DA. • Found impact of b2 on DA: zero value provides the

worse DA! Details to be checked.

27/08/2013WP2 TLM - 2.3 - MG

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