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Page 1: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 1

Aperture for AFP, ALICE, and LHCb (LHC)

M. Giovannozzi Acknowledgements: H. Burkhardt, B. Holzer, D. Macina, M. A. Gallilee, J. Jowett, G. Spigo

15/06/2012

Disclaimer: unless otherwise stated, nominal parameters are used.

Page 2: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 2

AFP layout - I

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Page 3: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 3

AFP layout - II• Layout provided by G. Spigo.• Defined maximum aperture markers

for MAD-X model:– Mechanical tolerances equal to those of

neighbouring magnetic elements, i.e., 0.84 mm radial, 0.36 mm horizontal.

– Aperture definition: maximum rectangle inscribed into real aperture shape.

• Defined installation of markers for Beam 1 and Beam 2 elements.

• Defined offset files.• No change in position between

injection and top energy.• All files (and sample job) available

under afs at ~giovanno/public/For_AFP

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Page 4: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 4

AFP aperture: results - I

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b*=11 mq=170 mradSep=2 mm

Page 5: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 5

AFP aperture: results - II

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Distance (m)

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b*=0.55 mq=142.5 mradSep=0.5 mm

Page 6: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 6

Alice beam pipe - I• New layout before LS2: certified (by M. A.

Gallilee) nominal layout.• New layout after LS2: certified (by M. A. Gallilee)

proposed layout.• S-dependent tolerances have been introduced

for both layouts.• Several configurations considered:– Nominal injection– Nominal collision – proton physics– Nominal squeezed - ion physics

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Page 7: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 7

Alice beam pipe - II

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LS2 aperture Nom apertureLS2 tol. Nom. Tol.

Page 8: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 815/06/2012

Alice aperture: results - I

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b*=10 mqext=170 mradSep=2 mm

• R = 17.2 mm, tol. = 5.1 mm -> n1 = 4.1 s• R = 19.2 mm, tol. = 5.1 mm -> n1 = 8.4 s

Page 9: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 9

Alice aperture: results - II

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b*=10 mqtotal=88 mradSep=0.5 mmb*=0.6 mqtotal=150 mradSep=0.7 mm

Page 10: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 10

LHCb beam pipe - I• New layout before LS2: certified (by M. A.

Gallilee) nominal layout.• New layout after LS2: certified (by M. A. Gallilee)

proposed layout.• S-dependent tolerances have been introduced

for both layouts.• Several configurations considered:– Nominal injection– Nominal collision – proton physics– Nominal squeezed – proton physics

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Page 11: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 11

LHCb beam pipe - II

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Page 12: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 1215/06/2012

LHCb aperture: results - I

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Page 13: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 13

LHCb aperture: results - II

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b*=10 mqtotal=370 mradSep=2 mmb*=3 mqtotal=265 mradSep=0.7 mm

Page 14: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 14

Conclusions for nominal LHC - I• AFP

– Current proposal is compatible with aperture requirements. It is also compatible with high-beat optics.

– Further aperture restrictions (installation of Ferrites) should be re-evaluated.– Compatibility between AFP and ALFA should be carefully assessed.– The AFP area will be completely changed in the HL-LHC era.

• Alice– Too small aperture at injection beyond -2 m from IP!– High-beta optics not considered: it will enhance the aperture problems.– Top energy configurations are fine.

• LHCb– No specific problems found.– V-crossing at top energy with b*=3 m considered: no problem found

• All the files for Alice and LHCb are available under– /afs/cern.ch/eng/lhc/optics/V6.503/aperture: nominal beam pipe– /afs/cern.ch/eng/lhc/optics/V6.503/aperture/as-built: upgraded beam pipe

Any feedback is more then welcome!15/06/2012

Page 15: Aperture for AFP, ALICE, and  LHCb  (LHC)

MG - LEB meeting 15

Conclusions for nominal LHC - II

An important remark: the running conditions after LS2 are not completely defined (or at least known to me). An exhaustive analysis is therefore not possible, to date.

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