# Presentation: 157400

## LARP Magnet R&D at FermilabAlexander Zlobin, Fermilab

- Outline:
- New generation IRQ

***brookhaven - fermilab - berkeley***

_**US LHC Accelerator Research Program**__**                              **_

## LARP

- Fermilab actively participated in launching the U.S. LHC Accelerator Research Program (LARP) and will continue play key role in the Program.
- The goal of LARP magnet R&D is to develop 2nd generation IR magnets for LHC to replace the 1st generation magnets.
- Contributions of Fermilab to LARP Magnet R&D include:
- conceptual designs studies of various magnets for 2nd generation LHC IRs
- participation in material and component development
- leading the IRQ short and long model magnet R&D
- design, fabrication and tests of full-scale prototypes of the LHC IR magnets
- Close BNL-Fermilab-LBNL collaboration and strong connection between the LARP magnet R&D program and the base High Field Magnet R&D programs is critical, in order to reduce risks and increase the probability of success.
- Base magnet R&D programs for Nb3Sn HFM should be able to demonstrate the possibilities and limitations for this technology during next couple of years.

## 1st Generation LHC IRs

- Baseline LHC inner triplets consist of single-bore, high-gradient quads based on NbTi superconductor.
- Quadrupole parameters:
- 70 mm coil aperture
- 205 T/m nominal gradient with 20% margin
- 1.9 K operating temperature

## 2nd generation Inner Triplet Design Options 

- Two fundamental inner triplet design approaches to 2nd generation LHC IRs:
- a) single-bore inner triplet design
- Quadrupoles with largest possible aperture are required, to provide largest beam separation and accommodate the large **-max.
- b) dipole-first designs with double-bore quadrupoles
- For these IR designs there are two contradictory requirements for IR quads:
- Large **-max requires large aperture
- Twin-bore configuration limits aperture

## Double-bore Inner Triplet Designs

- Examples of 2nd generation LHC IR optics based on double-bore inner triplet with 100 mm quads.

- Parallel apertures
- Non-parallel apertures

## R&D Questions 

- R&D questions:
- What is the optimal maximum field for new Nb3Sn IRQ?
- What is the optimum operation margin in the extreme radiation environment at very high luminosity?
- What is the IRQ optimum aperture for single-bore and double-bore quads?
- What is the optimal design for large-aperture Nb3Sn quads?
- Are non-parallel axis double-bore quadrupoles feasible?
- How to maintain good field quality in magnets over the full operating range?
- How to remove the large heat deposition (few kW) from the magnet cold mass?
- What are appropriate materials for operational conditions?
- These questions have to be addressed during conceptual design studies and model magnet R&D.

## Common Quadrupole and Dipole Features

- Many of R&D issues are common to new IR dipoles and quadrupoles:
- Conductor issues
- new Nb3Sn high-Jc strands
- Strand and cable stability, magnetization, degradation
- Maximum field and field quality
- Mechanics and high-stress management
- Coil cooling and heat transfer to cryogenic system
- Quench protection
- Materials and components (high radiation insulation)
- Technology: react and wind approach
- The tight connection and cross-talk of both magnet R&D directions and general technology development is natural and will lead to the high efficiency of the whole program.

## Phases and Milestones

- FY04-FY05 – conceptual design studies
- FY06 - start IRQ model R&D with simplified 1-m long models (2-layer design) in order to develop basic tooling and infrastructure and start basic technology development.
- FY07-FY10 - a series of short models will address the issues of magnet quench performance, field quality, mechanics, quench protection, reproducibility, long term performance, etc.
- FY08 - start studying length dependent effects with 4-m long coils, as soon as we achieve acceptable quench performance.
- FY10-FY12 - construction of one or more prototypes containing all of the features required for use in the LHC.

## FY04-FY05 goals and collaboration

- Establish baseline IRQ design for the first phase of short model R&D, including:
- magnet cross-section
- strand and cable parameters
- mechanical structure of magnet cold mass
- Continue conceptual design studies of D1 design, including:
- magnetic and mechanical design
- thermal design and analysis
- quench protection analysis
- Status of work at Fermilab in these areas will be presented by Vadim.

## Other areas for collaboration

- Nb3Sn strand and cable R&D:
- Strand testing
- stability and magnetization studies
- cable design, fabrication and testing
- Ic degradation and interstrand resistance studies
- Material and component development:
- ceramic or S2-glass insulation with ceramic pre-preg
- end part design and fabrication
- Test of radiation resistant impregnation materials based on liquid poliimid
- Quench heater design, fabrication and test
- Passive correction design, fabrication and test
- W&R technology:
- coil winding, curing, HT and impregnation techniques
- Splicing technology
- Tooling design
- Magnet assembly technique