# Presentation: 659461

## LARP Status & IssuesSteve Peggs

*State of LARP*
*	**- Mission, org chart, budget*
*Accelerator Systems*
*	**- Commissioning (various), “outreach”, IR upgrade*
*Magnet Systems*
*	**- CERN & LAPAC comments*
*	**- Quadrupole R&D paths, dipole first D1 *
*Collaboration organization*
*	**- Calendar, publications, membership, ...*
*Summary – Napa goals*

- Mirrors:  http://www.rhichome.bnl.gov/LARP    http://www-td.fnal.gov/LHC/USLARP.html

## Mission Statement (“elevator” version)

- 1)	To help make more luminosity, earlier
- 2)	To collaborate in an interaction region upgrade to make even more luminosity, later
- 3)	To use, develop, and preserve unique U.S. resources and capabilities
- 		(physicists, engineers, & infrastructure)
- “Outreach” needed, to our own communities – ATLAS, CMS, ILC, ... – demonstrating how LARP helps them

## Organization Chart

## Budget profile – April 2004

- After adding
- Phase II
- collimator R&D (SLAC)
- This $11 M guidance for FY06 still holds good ...

## FY05 budget – Sept 04

## FY05 budget – Oct 04 DRAFT

- FY05 budget – Oct 04 DRAFT

## Slide 7

## Accelerator System milestones - 1

## AS milestones - 2

## AS milestones - 3

## Installation & Commissioning Schedule

- A major realistic LHC re-scheduling is going on ...
- “The consequence (of the QRL problem) on the schedule will only be clearly assessed when installation restarts (Nov 1) and is running smoothly” Lyn Evans, HEPAP 9/30/04
- This impacts “Hardware Commissioning” planning (for U.S. built deliverables from the “construction program”) ...
- ... and squeezes pre-beam system integration commissioning, especially if first beam is held to May 2007

## System Integration Commissioning (1)

- “Biggest worry is the enormous job of hardware commissioning”
- Lyn Evans, HEPAP, 9/30/04
- Example: getting LHC to ramp at full speed, with fully synchronized sub-systems (800 power supplies, quench protection, cryo, vacuum, & control systems?)  Is this a good example?
- LHC seeks a “nucleus of experience people” from U.S. labs, with critical engineering skills - at the interface of the magnet, cryogenic, and quench protection systems?
- Roberto Saban has a clear statement of required resources to be presented and discussed at Napa
**This is clearly within the LARP mission**

## System Integration Commissioning (2)

- BNL and FNAL directorates have expressed unambiguous support for a LARP role in System Integration Commissioning (pre-beam)
- Funding from inside the present LARP budget is challenging ...
- Where are the experts - BD, TD, C-AD, .... ?
- As with Beam Commissioning, we must begin to name names

## Interaction Region Upgrade

- Quad or Dipole first?
- 120 parasitic long range beam-beam collisions give a challenging problem at higher beam intensities.
- Dipole first layout reduces long-range Beam-Beam interactions
- BUT
- Larger β* at fixed βmax
- Higher energy deposition in D1 from charged particles
- There are other ways to handle BB?

## Ruggiero et al, EPAC - 1

- “Nb3Sn technology
- - appears to be the only candidate for a more substantial improvement
- - could open upgrade scenarios such as 'dipole-first'”
- “Important issues related to long Nb3Sn magnets need to be addressed by vigorous R&D”
- “The choice of the **coil aperture is driven more the power density limit** than by the beam acceptance”!
- “An estimate of the radiation parameters of the magnets requires extensive simulations based on detailed knowledge”

## Ruggiero et al, EPAC - 2

- 	- large crossing angles with superbunches or crab cavities
- 	- or the 'dipole-first' option
- “The effective Nb3Sn filament diameter (>100 ) is too large” (Material development required.)
- Coil thermal stability arguments favor superfluid helium cooling (1.9 K)
- 	- NbTi cable has significant helium porosity
- 	- Nb3Sn cable to date is fully impregnated

## “LAPAC suggests that the main issue is demonstration that (Nb3Sn) quads can be made in both long and short lengths.”

- “LAPAC suggests that the main issue is demonstration that (Nb3Sn) quads can be made in both long and short lengths.”
- “... **demonstration of a working long quadrupole,** the first of its kind in the world, will be a key element in the decision to start ... the LHC luminosity upgrade.”
- “(Dipole) work is focused on the ‘dipole first’ scenario, which must meet the most severe requirements; an open mid-plane design ... 15 T, 10 m”
- “Since the new IR layout ... is not known, ... recommend against going further than ... to deliver a low cost and simple (dipole) demonstration model ...”
- We don’t necessarily agree fully, but the comments are telling

## Both paths have strengths & weaknesses in “going long” 	(incapacity of brittle Nb3Sn to support pre-stress)

- Both paths have strengths & weaknesses in **“going long”** 	(incapacity of brittle Nb3Sn to support pre-stress)
- Optimum design may involve one or both technologies

## Racetrack coils                Cosine theta coils

- Both configurations have strengths & weaknesses ...
- How many kW of irradiated power?  What IR layout?
- Need real beam experience, even with an 2012 upgrade
- For now, opticians can assume G x A = constant ?

## “Dipole first” layout separation dipole

- There are potential benefits to the open mid-plane approach

- A dipole first IR requires a dedicated D1 design that:
- 1) Doesn't quench with ~8 kW of energy deposition, with high field and adequate field quality
- 2) Manage the heat load in a cryogenically friendly fashion >> 4K

- “Dipole first” layout separation dipole

## Separation dipole D1

- At Napa:
-  -	compare a revised open midplane separation dipole with a
- 		cos theta dipole
-  -	present radiation heating calculations
-  -	discuss whether to continue with a separation dipole 	design study
- If “no”, document work by end of CY04
- Separation dipole review at BNL in December

## “Outreach” - Tevatron cf LHC

## Kinetic energy

- 	- 1 small aircaft carrier of 104 tonnes going 30 kph
- 	- 450 automobiles of 2 tonnes going 100 kph
- Chemical energy
- 	- 80 kg of TNT
- 	- 70 kg of (swiss?) chocolate
- Thermal energy
- 	- melt 500 kg of copper
- 	- raise 1 cubic meter of water 85 C: “a tonne of tea”

## “Outreach” - snapback transients

- Vortex currents circulate quantum fluxoids pinned in a Type II SC filament
- A quadratic fluxoid density gradient drives a current gradient ...
- Like eddy currents, “persistent currents”
-  - depend on the “external” field history
-  - decay (SLOWLY) with time
-  - unwind with vicious transients!

## Calendar

- Nov	  8-11	CARE "Beam Dynamics in Future Hadron Colliders ..", CERN
- Nov	13-16	International Linear Collider workshop & SC meeting, KEK
- Nov	 	??	Luminometer Technical and Cost review, LBNL
- Dec	  1- 2	CARE "Beam current msmts & fast lifetime calculations", Lyon
- Dec	15	Quarterly Report deadline
- Dec		??	Abort Gap Monitor engineering feasibility study white paper
- Dec		??	Dipole Design Feasibility review, BNL
**2005**
- Jan 		??	Tune Feedback workshop, BNL (2 days)
- Jan	17-21 ? 	"Chamonix 05", CERN
- Jan	31	Define LARP Beam Comm/LHCOP integrated plan
- Feb		??	Tune Feedback Cost and Technical Review, BNL
- Mar	  8-10 ?	**LARP collaboration meeting 4, near FNAL**
- Mar	15	Quarterly Report deadline
- Apr 		??	Phase II Collimators Go/No Go decision
- May	16-20	Particle Accelerator Conference, PAC05, Knoxville
- Jun		??	**LARP Advisory Committee, LARPAC, FNAL**
- Sep	19-23	Magnet Technology MT-19, Genova
- Oct		??	**LARP collaboration meeting 5, near BNL**

## Organization

**Hypothesis: LARP is similar to an HEP experiment**
- If so, need to establish rules for:
- 	- collaboration membership
- 	- journal & conference publications
- 	- author listings
- 	- speaker invitations
- Also need to establish
- 	- internal technical notes
- 	- fixed terms for some positions
- 	- internal technical review mechanisms
**Discussion & comments?**

## Summary – Accelerator Systems

- 1)	Finalize Task Sheets for FY05, develop those for FY06
- 2)	Re-evaluate milestones, especially those imminent for instrumentation
- 3)	Stabilize the definition of “Phase II Collimator R&D” task
- Commissioning tasks/organization/scope need re-consideration
- Begin naming names ...(commissioning)
- Discuss and evaluate potential new tasks – eg “future instrumentation”
- Chart a road map for IR layout resolution

## Summary – Superconducting Magnets

- 1) The program MUST be mature and unified, or ...
- 2) Task sheets and milestones
- 3) Relationship of LARP program and base program:
- 	- Develop technology for future U.S. machines (BROAD)
- 	- Focused to meet LHC upgrade in 2012 (NARROW)
- 4) Mechanisms for collaborative internal technical decisions
- 5) Can long Nb3Sn magnets be built?
- 6) Integrate energy deposition & heat removal analyses

## Summary - General

- 1) “Outreach” to our own communities – ATLAS, CMS, ILC
- 2) Retain an open door policy to potential additional tasks – even though the hurdle is very high
- 3) Seek to understand the complementary(?) role of CARE
- 4) Uncertain schedule affects planning, directly and indirectly
- 5) Addtitional DoE reporting/reviewing is coming ...
- 6) Organize LARP like an HEP experiment, for the same reasons?