# Presentation: 004613

## LAUC Proposal:  Feedboxes and System Engineering

***bnl - fnal - lbnl - slac***

_**US LHC Accelerator Research Program**_

**	****	**

**Michael Lamm**
**LARP+LAUC  DOE Review**
**June 21, 2008**

**Proposal**
**Motivation**
**What the present IR looks like **
**System Ideas for new IR**
**How we could participate**
**Conclusion**

## Proposal Summary

- Play a lead role in the Phase 1 IR System Design
- Cryogenic engineering
- Powering/Quench Protection
- AP support

- Supply all or part of the cryogenic/power distribution boxes

## Motivation to Participate in Phase I IR Upgrade

- Benefit to CERN is our unique experience/expertise
- U.S. responsible for much of the existing IR system components and system design
- Major contributor to ongoing LHC program via LARP Hardware and Beam Commissioning

-  Benefit to U.S.
- Supports LARP goals (general and Nb3Sn Magnet)
- State-of-the-art accelerator component design
- Modest investment, sizable contribution
- Support US HEP (higher luminosity, faster)

**Present High Luminosity IR Layout**

- Resistive “D1”

**Two styles of IR Quads, MQXA(KEK)  and MQXB(FNAL): same aperture and operating gradient; different inductance and powering**
**Resistive D1  (SC D1 in low luminosity regions supplied by BNL)**
**Distributed correctors built into Quad coldmass**
**In-line cryo/Power Feedbox  (DFBX)**
**No extraction circuit, all heaters fire under quench condition**

## Latest Ideas from CERN for Phase I IR

- IR Quadrupoles:  Wider aperture, lower gradient, longer length: New Layout!
- D1 wider aperture magnets (superconducting)
- Local corrector magnets may be incorporated into a single box
- Quads operate in 1.9K, D1/correctors 4.2 K TBD
- Layout argues for **new cryo/power distribution boxes**
- Large stored energy argues for **new powering scheme** including extraction circuits

## Present idea for Powering New IR Quads

**Present idea for Powering New IR Quads**

**Identical Magnets powered in series**

- Presentation by K.H Mess (Dec. 2007)

## Powering Issues

- Extraction Circuit ?
- Benefit depends on propagation of quench energy through helium vs. energy extraction efficiency
- Analysis of phase I IR quad thermal model
- Quench analysis of Cryogenic/power feedbox
- Data collected now during commissioning provides insight

## Powering Issues II

- Cold vs. Warm diodes
- Less reliable/less accessible but would reduce number of high current leads
- Experience with diodes in present LHC
- Cold in arcs, warm in IR’s
- Experience with HTS lead design
- Effect of transient high current

## Existing feedboxes not matched to phase I needs

**Phase I requires 12kA power leads**
**Phase I needs SC D1 power distribution**
**Space is very cramped with existing boxes**
**No spare power boxes, no spare leads...**

**Electrical QA Tests on DFBX**

**Existing cryostat and power interfaces don’t match new system requirements**

## New Feedbox strategies

**While many solutions are being considered the favored solution is to build new boxes, placed in a low radiation-accessible alcove**
- Easy access to feed box and power leads
- All boxes built ~the same (no need for L/R, uphill, down hill)
- SC link from feedbox to magnets. Highly desirable to use  HTS or MgB2 since it can be cooled by He gas and therefore need only room temperature gas outlet
- HTS leads (MgB2 or 2G YBCO considered)

## HTS leads ~ 30 Meters from beam line

- Access control
- Removable

## In position to take lead in system design

- USLHC was responsible for the Cryogenic Design of the existing IR
- Provided existing DFBX including HTS leads!
- Electrical design including, heater specs, buswork and expansion loops
- Leadership position in LHC HC
- Responsible for CERN DFB cryo commissioning as well as DFBX retrofits.
- Presently responsible for both cryo and electrical commissioning of DFBX

## Cryogenic Contributions 

- US would take a lead role in the cryogenic design of Phase I IR
- Evaluate performance of existing system
- Calculate static/dynamic heat loads
- Review magnet thermal design
- Review heat exchanger location efficiency
- Propose cryogenic instrumentation

## Cryogenic Effort/Schedule

- Cryo must be determined early in the IR design!
- No major mods to cryoplant envisioned
- Magnet environ. (mass, cooling req., oper. temp)
- Powering scheme
- Will require expensive effort starting no later than Fall FY09 (preferably ASAP)
- Will require extended stays at CERN (2-3 weeks, 3-4 times over the next 12 months)
- Mostly cryo engineers not presently working on LARP

## System  Powering/Quench Protection

- Proposed areas of concentration:
- Quench protection integration
- Quench protection studies
- Power supply specifications
- Feedbox powering especially, SC link and SC power leads
- Design/specification of internal bus work, internal wiring

- Interesting engineering and magnet science task

## Proposed Quench/Powering Effort

- Two LARP quench protection experts stationed at CERN till January 2009 for HC
- Propose to CERN that some effort be diverted to this task starting in the Fall
- This work must be done in close conjunction with CERN powering/quench protection group  so task is well matched
- Expect extended visits to CERN beyond January 2009 is needed
- Segue from HC to Upgrade

## Accelerator Physics Issues 

- Based on our experience with the present IR Quads, there are several IR related AP topics beyond the basic optics design:
- Strength and Location of Corrector Magnets
- Effect of Internal Alignment of IR quadrupoles
- Expect to be more critical in Phase I
- Energy deposition studies
- Impact on IR absorber design
- Propose ~0.5 FTE AP effort
- Redirection on LARP JIRS?

## Propose to supply cryogenic feedbox

- CERN plans for phase I feedboxes are being  discussed now as part of the LHC IR working group
- Detailed plan depends on results of cryo, powering and quench protection system TBD
- Most of the effort in the next 12 months will go towards making a design and detailed cost and schedule analysis, however...
- Based on present feed boxes, cost of HTS and cryo distribution lines, we estimate ~$1500k/complete feedbox. (not including EDIA)

## Cryo/power feedbox issues

- Feedbox schedule will be challenging conceptdesigndelivery by 2013
- Do-able based on our extensive experience with existing feedboxes
- In some ways simpler device because there are less space constraints
- Institutional memory; will benefit from lessons learned in existing DFBX
**CERN must commit to functional specs within 6 months**

## Cryo/power feedbox issues

- SC link will be a challenge but do-able
- Tight space, 40 m run with brittle material
- Part of mission is to consider all reasonable options including resistive or LTS links
- Ongoing discussion with MgB2 vendors in U.S. and Europe
- U.S. supported YBCO transmission lines
- Expect collaboration with CERN power lead expert along with our own experts
- Build 10 meter prototype in FY10

## Summary of Required Effort in FY09

- Goal: Feedbox design for CD02
- Experience shows in house design must be well beyond concept for real cost estimate
- SC link and SC power leads is not off the shelf
- Design 10 meter prototype link and test
- System design closely linked!
- Effort in FY09:   ~3 FTE’s (1.5 FTE drafter, 1.5 FTE Cryoengineer, 0.5 FTE physicist)

## Summary of Required Effort in FY09 II

- To make an impact and meet our delivery schedules, the system design must be solved in some detail prior to the CERN TDR.  For FY09
- Cryo design   (0.75 cryo engineer)
- Powering Scheme (0.5 FTE physicist)
- AP studies (0.5 FTE physicist)
- ~2 FTEs

## Cost Estimate and Milestones Summary

- Functional and Interface specs for IR: January 2009
- CD2 summer 2009
- Order Feedboxes:  No later than January 2011
- String test at CERN (deliver first DFBX)  Jan 2012
- Start installation:  Jan 2013

## Conclusion

- U.S. is in a unique position to contribute to the phase I IR System Design and Feedbox
- Tasks aligned with U.S. long term goal for Nb3Sn IR quads and advanced accelerator technology
- New feedboxes with HTS/MgB2 is a technically interesting project with high success probability
- Only modest effort required, should not have major effort impact on Nb3Sn program.
- System design needs to start NOW.  Feed box design needs to start this year; construction in 2010-12