New ALICE Beam Pipe: Injection Protection

New ALICE Beam Pipe: Injection Protection

C. Bracco on Behalf of ABT/BTP Acknowledgment: M. Giovannozzi

Outlines

Reminder Assumptions Aperture and beam envelope: Nominal injection Grazing event (MKI failure) Conclusions

Reminder

To protect the LHC aperture at injection (bottleneck in the arc) and

respect the collimation hierarchy: LHC injection protection collimators (TDI, TCLIA and TCLIB) ar at 6.8 s TCDI (in the TL) are at 4.5 – 5 s

Reminder

Alice aperture: results - I

Ok!...check MKI grazing failure..

M. Giovannozzi

b*=10 m qext=170 mrad Sep=2 mm

Minimum aperture = 13 s (bottleneck in the arc)

4 s bottleneck in the experiment

18/07/2014

MG - TREX meeting

5

Reminder

90% MKI strength

10% MKI strength

Assumptions

Only MKI failures are considered :Only vertical plane Normalised emittance of 3.5 mm mrad also for postLS2 case Optics for protons (minimum n1):b* = 10 m, crossing angle = 170 mrad , separation =2 mm Beam envelope: 6.8 sb (what can go through TCDIs and TDI) Aperture: Mech.aperture* – Mech.tol.* – Orbit** – Disp.offset * Data from ALICE and Massimo ** 3 mm *sqrt(b/max(b)) ** Dy*3e-4

Aperture and Beam Envelope PreLS2

Nominal kick

TDI

TDI

Aperture and Beam Envelope PostLS2

Nominal kick

TDI

TDI

Phase Advance Min

Aperture- MKI

Grazing Event

grazing (10% MKI kick)

TDI

Nominal MKI kick

TDI

Conclusions

The new proposed aperture fulfills the n1 requirements of collimation hierarchy: bottleneck kept in the arc and > 7.5 s No direct beam impact on the new aperture is expected also in case of the most critical MKI failure (grazing event) Recommendation: calculate energy deposition induced by secondary showers in case of grazing event.