# Presentation: 804609

## Superconducting Magnet R&Doverview

- Alexander Zlobin, Fermilab
- For BNL-FNAL-LBNL Collaboration

***brookhaven - fermilab - berkeley***

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

## LHC upgrade goals and phases 

- Nominal baseline parameters:
- -luminosity Lnom=1034 cm-2 s-1
- -beam energy Enom=7 TeV per beam
- LHC upgrade goals:
- -luminosity L=(3-10)Lnom
- -beam energy E=(1.5-2)Enom
- LHC upgrade phases:
- -Phase 1 – luminosity upgrade with hardware changes outside the arcs
- -Phase 2 – energy and luminosity upgrade with major hardware changes throughout LHC accelerator complex
- At present time US LHC ARP is mainly focused on the preparation to and participation in the LHC luminosity upgrades

## Luminosity upgrade recipes 

- Reduce *****
- Increase crossing angle
- Increase beam intensity
- 	 L=3.31034 cm-2 s-1
- Halve bunch length
-  L=4.71034 cm-2 s-1
- Double number of bunches
- 	  L=9.41034 cm-2 s-1
- Reduce longitudinal emittance
- The IRs are among the systems limiting the LHC performance. Replacement of the existing inner triplets is a key step to higher luminosity.
- The present LHC IR quadrupoles have a radiation lifetime of 6-7 years at nominal luminosity. We must be prepared to replace them by about 2014.

## Inner triplet designs 

- Two fundamental inner triplet designs:
- -single-bore inner triplet followed by the separation dipoles
- -Double-bore inner triplet with separation dipoles first
- Two approaches to the LHC high-luminosity inner triplet upgrade:
- - present inner triplet optic layout with new single, large-bore high gradient quadrupoles and correctors
- - new inner triplet optic layout with twin, moderate-aperture high gradient quadrupoles and correctors and very high field separation dipoles

## What kind of magnets do we need?

- In all upgrade scenarios we need new IR quads and correctors, and in case of D1 first – high-performance separation dipoles
- Target parameters and operation conditions of upgraded LHC high-luminosity IRs push magnet technology to the limits that exceed the present level of IR magnet technology
- The magnet R&D program address the following issues:
- IR magnet design
- SC strand, cables and components
- Technology
- Performance

## Magnet R&D program goals 

-    Evaluate possibilities and limitations of luminosity upgrade related to the IR SC magnets (in collaboration with AP group)
- Develop high performance prototypes and technologies of superconducting magnets for high-luminosity inner triplets including
- Large-aperture, high gradient quadrupoles
- High-field beam separation dipoles and/or strong correctors
- Program focuses on Nb3Sn, large-aperture quadrupoles.
- Initial program is to develop technologies, not specific designs.
- Specific design choices will be made after several years of magnet R&D and related accelerator design studies.

## Magnet R&D directions 

- 1. Magnet R&D
- Issues: optimal magnet designs (IRQ, correctors, separation dipoles) and performance
- 2. Superconductor and cable R&D
- Issues: Nb3Sn strand and cable design and parameters for IR magnets
- 3. Technology R&D
- Issues: wind-and-react (baseline approach) vs. react-and-wind technique for Nb3Sn IR magnets
- More details will be presented in the separate presentations.

## Conceptual Design Studies

- FY 2002-2004
- Establish magnet target parameters (with US and CERN AP groups).
- Aperture, field strength, field quality, single vs. twin aperture, coil geometry, ...
- Develop and compare different design and technological approaches for quads, dipoles and correctors.

## Experimental R&D

- FY 2003-2009
- Magnet R&D
- Fabrication and tests of 70 mm shell-type Nb3Sn quadrupole models using existing mechanical design and tooling for baseline IR quadrupoles.
- Fabrication and tests of 90 mm shell-type Nb3Sn quadrupole models based on D20 tooling.
- Fabrication and tests of simple Nb3Sn quadrupole models based on racetrack coils
- Development and study of final IR quadrupole short models.
- Long coil problem studies, life-time tests.
- Start development of large aperture, high-field dipoles and/or correctors ... depending on collaborative interest by CERN and KEK.
- SC and cable R&D
- Evaluation of different Nb3Sn strands.
- Development and optimization of Nb3Sn cables for IR model magnets.
- Technology R&D
- Investigation of react-and-wind and wind-and-react technologies.
- Technology optimization for final magnet designs.

## Full-scale prototypes

- FY 2009-2011
- Final design decisions follow initial LHC operational experience.
- Fabrication and tests of large-aperture single or twin-aperture quadrupoles  (final design and technology) – full length in prototype cryostat.
- Fabrication and tests of large-aperture dipoles and/or correctors (depending on collaborative interest by CERN and KEK).

## Magnet R&D Program schedule

- The number of models is consistent with the program goals.
- It will be corrected depending on
- budget available
- results achieved
- collaboration interests

## Milestones

- FY2004:
- selection of the new IR optics, baseline magnet design and technology, SC cable and components
- correction of the material and technology R&D
- FY2006:
- start dipole/corrector R&D in collaboration with CERN
- FY2008:
- start the prototype design including the magnet cryostat
- FY2011:
- Final design report
- deliverable: complete design package, ready to manufacture.
- decision on LHC high-luminosity IR upgrade plan and schedule (CERN)
- who (US, CERN, KEK, industry) builds which IR upgrade magnets.
- decision on next phases of LHC upgrade

## BNL/FNAL/LBNL Collaboration 

- The work will be performed by the collaboration of magnet groups from three U.S. national Labs. BNL, LBNL and Fermilab have:
- strong magnet teams capable of efficiently solving complex problems related to the SC accelerator magnet design and technology development, magnet fabrication and tests
- unique infrastructures that allows extensive engineering, fabrication and testing of SC magnet models and prototypes, structural material and component studies including SC strands and cables
- SC accelerator magnet programs which has already resulted in developing innovative magnet designs and techniques, and obtaining unique experimental data related to magnet and component performance parameters
- We are planning to involve universities and industry in the R&D (especially in SC and material development).
- Collaboration basic principle: The Program is driven primarily by the technical considerations to meet the US LHC ARP goals, and will be carried out based on optimal use of the three labs resources.

## Collaboration with CERN and non-U.S. Labs 

- The work will be performed in collaboration with CERN and other non-U.S. magnet groups working in the field of superconducting accelerator magnet technologies.
*Nature of collaboration with CERN and KEK yet to be established.*
- US-CERN-KEK collaboration meeting on IR upgrade, 11-12 March 2002.
- The status of Nb3Sn high field magnet development in 3 U.S. Labs (Fermilab, BNL, LBNL), CERN and 3 European institutions (CEA/Saclay-France, INFN-Italy and Twente University- Netherlands) and KEK, and future plans have been reviewed.
- All magnet groups demonstrated interest to the development of high field accelerator magnets for the LHC upgrades. However, a lack of funding and concentration of all resources on the LHC construction do not allow performing this work at CERN during next 4-5 years.
- Second meeting is planned for November 2002.

## Why do we need LHC ARP Magnet R&D?

- It is generic since it addresses the most important issues related to the IR designs for high luminosity machines.
- It is practical since it is related to a real machine.
- It extends the expertise of BNL, Fermilab and LBNL in IR magnet designing, fabrication and testing.
- It is an opportunity to develop new Nb3Sn accelerator magnet technology and use it in a real machine.
- It stimulates industry in development of new materials, and Nb3Sn strands and cables for HEP.

## Outcome of the LHC IR magnet R&D

- _US LHC collaboration_:
- magnet and component specifications needed for the detailed design of new LHC high-luminosity IRs
- the designs and technologies of Nb3Sn quadrupoles and other magnets suitable for the LHC high-luminosity IR upgrade
- the IR quadrupole cold-mass full-scale prototype and tooling
- the cost and the schedule for the LHC IR upgrade
- _VLHC program_:
- the conceptual design and the cost of the VLHC interaction regions will be justified
- strong international collaboration of accelerator physicists and magnet developers will exist