# Presentation: 658456

## IRQ design comparison:shell-type vs. block-type

- Paolo Ferracin
- LHC IR Upgrades workshop
- St. Charles, IL USA
- October 3 - 4 , 2005

## Motivations and goals

- Definition of a strategy to compare block-type and shell-type quadrupole magnets
- Magnet requirements for an LHC luminosity upgrade application
- Investigate block-type quadrupole magnets (racetracks) as an option for a luminosity upgrade
- Perform a comparison analysis

- Paolo Ferracin

- 10/03/2005

## Shell-type vs. block-type

- Previous work: V.V. Kashikhin, *et al.*, “2nd generation LHC IR quadrupoles based on Nb3Sn racetrack coils”, *EPAC 2004.*

- Paolo Ferracin

- 10/03/2005

## Comparison strategy

-  Requirements for a luminosity upgrade scenario
-  Accelerator physics
- Aperture and beam envelope
-  Magnetic design
- Gradient and field quality (systematic and random errors)
-  Mechanical design
- Coil pre-stress and support structure
-  Energy deposition
- Absorber and LHe channel
-  Quench protection

- Paolo Ferracin

- 10/03/2005

## Upgrade scenario*

- Phase 1:  increase of luminosity with hardware changes only in the interaction regions
*β*** **= *0.25 m
- σ = 2.185 mm
- Dtrip = 78.5 mm
-  77 mm (T. Sen, *et al.*, 2001)
-  Increase the triplet magnet diameter
-  Same gradient
- Gnominal ~ 200 T/m
- Gshort sample ~ 250 T/m
- L = 4 - 5 x 1034 cm-2s-1
- *O. Bruning, *et al.*, “LHC luminosity and energy upgrade: a feasibility study”, ***LHC Project Report*** 626 (2002)

- Paolo Ferracin

- 10/03/2005

## Comparison strategy

-  Requirements for a luminosity upgrade scenario
-  Accelerator physics
- Aperture and beam envelope
-  Magnetic design
- Gradient and field quality (systematic and random errors)
-  Mechanical design
- Coil pre-stress and support structure
-  Energy deposition
- Absorber and LHe channel
-  Quench protection

- Paolo Ferracin

- 10/03/2005

## Coil aperture and beam envelope*

- The aperture of the triplet magnet must provide enough space to enclose:
- 		Dtrip > 1.1 x (7.5 + 2 x 9) · σ + 2 x 8.6 mm
- 9 σ of the beam envelope per beam
- 7.5 σ of beam separation
- 20 % of *β**-*beating (factor 1.1)
- 8.6 mm
- 3 mm of peak orbit excursion
- 1.6 mm of mechanical tolerances
- 4 mm spurious dispersion orbits (horizontal)
-     *O. Bruning, *et al.*, “LHC luminosity and energy upgrade: a feasibility study”, ***LHC Project Report*** 626 (2002)

- Paolo Ferracin

- 10/03/2005

## Coil aperture and beam envelope

- Shell-type

- Block-type

- Paolo Ferracin

- 10/03/2005

## Coil aperture and beam envelope

- Shell-type

- Block-type

- Paolo Ferracin

- 10/03/2005

## Shape of beam envelope

- Dtrip > 1.1 x (7.5 + 2 x 9) · σ + 2 x (1.6 + 3 + 4) mm

- Paolo Ferracin

- 10/03/2005

## Coil aperture and beam envelope

- Dtrip = 78.5 mm

- Paolo Ferracin

- 10/03/2005

## Comparison strategy

-  Requirements for a luminosity upgrade scenario
-  Accelerator physics
- Aperture and beam envelope
-  Magnetic design
- Gradient and field quality (systematic and random errors)
-  Mechanical design
- Coil pre-stress and support structure
-  Energy deposition
- Absorber and LHe channel
-  Quench protection

- Paolo Ferracin

- 10/03/2005

## Magnetic design: coil aperture and field quality

- Phase 0: Dtrip = 60.4 mm; Rref = 17 mm
- Phase 1: Dtrip = 78.5 mm; Rref ~ 22 mm

- Paolo Ferracin

- 10/03/2005

- Magnetic design: block-type coil geometries

- Paolo Ferracin

- 10/03/2005

## Magnetic design: gradient and field quality

- TQ-v1 cable (27 strands)
- Jc = 3000 A/mm2
- 1.9 K
- Harmonics < 0.05 at Rref

|  | Inner | Outer |
| --- | --- | --- |
| Iss [kA] | 13.3 |  |
| N turns | 26 | 37 |
| Bss [T] | 13.9 | 13.3 |
| Gss [T/m] | 251 |  |
| SC area [cm2] | 52 |  |

- Paolo Ferracin

- 10/03/2005

## Comparison strategy

-  Requirements for a luminosity upgrade scenario
-  Accelerator physics
- Aperture and beam envelope
-  Magnetic design
- Gradient and field quality (systematic and random errors)
-  Mechanical design
- Coil pre-stress and support structure
-  Energy deposition
- Absorber and LHe channel
-  Quench protection

- Paolo Ferracin

- 10/03/2005

## Mechanical design: support structure

- Aluminum shell
- Iron yokes
- Stainless steel pad
- Stainless steel poles
- Stainless steel mid-plane spacers
- Aluminum bore

- Paolo Ferracin

- 10/03/2005

## Mechanical analysis: coil and bore stresses

- Coil stress < 170 MPa

- Bore stress < 150 MPa (293 K, 4.3 K and excitation)

- Paolo Ferracin

- 10/03/2005

## Comparison strategy

-  Requirements for a luminosity upgrade scenario
-  Accelerator physics
- Aperture and beam envelope
-  Magnetic design
- Gradient and field quality (systematic and random errors)
-  Mechanical design
- Coil pre-stress and support structure
-  Energy deposition
- Absorber and LHe channel
-  Quench protection

- Paolo Ferracin

- 10/03/2005

## Energy deposition and quench protection

- For a given luminosity upgrade
-  Heat deposition on the coil
- Effect on coil temperature margin
-  Radiation dose
- Effect on component lifetime
- Next step
- Design of absorber and LHe channel
- Peak power density below quench limit with safety margin (about factor 3)
- Limit on the radiation damage
- Second iteration on coil geometry to meet requirements
- Beam envelope
- Gradient and field quality
- Support structure
- Quench protection

- Paolo Ferracin

- 10/03/2005

## Conclusions

- Definition of a comparison strategy for shell-type and block-type quadrupole magnets
- List of requirements for a given luminosity upgrade scenario
- Investigation of a block-type quadrupole magnet as an option for a luminosity upgrade
- Next step
- Energy deposition studies
- Quench protection
- Second iteration of magnetic and mechanical design
- Shell-type vs. block-type comparison

- Paolo Ferracin

- 10/03/2005

## Coil aperture and beam envelope

- Questions
- Which is the relation between beam separation (7.5 σ) and crossing angle?
- Is Dtrip the “worst condition” (injection, nominal,...)?

- Paolo Ferracin

- 10/03/2005

## Magnetic design: coil aperture and field quality

- Question
- Which is the relation between beam envelopes  (2 · 9 σ) and Rref ?

- Paolo Ferracin

- 10/03/2005

## Phase 0

- L = 1034 cm-2s-1
*β*** **= *0.5 m
- σ = 1.54 mm
- Dtrip = 60.4 mm
- Absorber (beam pipe) thickness = 3 mm
- LHe channel      thickness = 2 mm
- Dcoil = 70 mm
- Gnominal = 215 T/m
- Gshort sample = 257 T/m

- Paolo Ferracin

- 10/03/2005