# Presentation: 314951

## Accelerator PhysicsSteve Peggs, BNL

**Recent activities**
**CERN LHC Upgrade Task Force**
**Phase Locked Loop workshop**
**LARP AP topics**
**Integration issues**
**Beam experiments**
**Summary**

## Recent ActivitiesCERN LHC Upgrade Task Force

## LHC IR Upgrade Collaboration meeting, CERN, March 2002

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## Phase Lock Loop workshop, June 10 & 11, CERNCERN(many) BNL(5)  DESY(2) GSI(2)

- The size of the **LHC** stresses the early establishment of **feed forward and feed back**** on tunes and chromaticities up the energy a**cceleration ramp.
- This requires Phase Lock Loop (PLL) instrumentation, **similar to the systems now/soon functioning in RHIC, HERA-e/p, Tevatron**
**Full confidence in PLL based operation is also of vital interest to a future US hadron machine:**
- reduce tight tolerances on magnet performance
- reduce magnet costs.

## Many accelerators have experimented with PLLs, finding it difficult to achieve robust and reliable performance
It is necessary to develop more confidence with the mathematical underpinnings, including filters, DSP code, and beam dynamics modeling, et cetera.
Conjecture: need to develop confidence through a joint Instrumentation and Accelerator Physics effort.

- It is necessary to **develop more confidence with the mathematical underpinnings,** including filters, DSP code, and beam dynamics modeling, et cetera.
**Conjecture**: **need to develop confidence through a joint Instrumentation and Accelerator Physics effort.**

## Eg, 4 methods to measure chromaticity up a ramp:
 Fast phase modulation (f >> fs)	Bruning (CERN)
 Slow phase mod ("traditional")	Tepikian (BNL)
 Slow PM (vector analyzer)		McGinnis (FNAL)
 Head-tail								Schmickler(CERN)
Four efforts led by 2 physicists and 2 engineers
An apples to apples comparison is possible?
[Note special BNL/CERN relationship (MoU)]

-  Fast phase modulation (f >> fs)	Bruning (CERN)
-  Slow phase mod ("traditional")	Tepikian (BNL)
-  Slow PM (vector analyzer)		McGinnis (FNAL)
-  Head-tail								Schmickler(CERN)
**Four efforts led by 2 physicists and 2 engineers**
**An apples to apples comparison is possible?**
**[Note special BNL/CERN relationship (MoU)]**

## Traditional slow modulation at RHIC (Tepikian)

**Traditional slow modulation at RHIC (Tepikian)**

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## LARP AP topicsThe Beam-Beam Interaction

**Coherent modes seen for first time (hadron) at RHIC**
**Tevatron Run 2 faces fundamental beam-beam issues**
**Electron lens compensation (FNAL)**
**Wire compensation (CERN)**
**RHIC is a flexible test bed**

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## Electron Cloud

**The electron cloud effect is expected to be very important at the LHC**
**Currently a hot bed of activity, both hadron and electron**
**There are indications that electron cloud is important at RHIC (as well as APS, SNS, PEPII, KEKB, ...)**

## Slide 19

## Nonlinear dynamics

**Nonlinear dynamics emain, as ever, a fundamental limit to storage ring performance**
**Analysis tools (such as SUSSIX) have developed significantly since SSC/E778 days**
**Availibility of AC dipoles promises a new era of linear and nonlinear dynamics studies**
**LHC considers an AC dipole, RHIC is commissioning two (H & V)**
**Another prime candidate for joint experimentation**

## Interaction Region Compensation

**The LHC IR correction scheme is similar to that at RHIC**
**Ongoing correction studies at RHIC are part of machine development time**
**These issues are enhanced in LHC IR upgrade scenarios**

## Slide 22

## Energy deposition and Beam Loss Scenarios

**The stored energy of the LHC beam - ****350 MJ**** - is in a new parameter regime**
**These issues will be even more extreme in any VLHC**
**Fermilab has unique resources in support of both unavoidable energy deposition, and also accident scenarios**
**Accident scenarios are currently under intense scrutiny at LHC**
**IR Upgrade scenarios also push stored energy and energy deposition issues**

## Heavy Ion Operation

**The design goals of the LHC also include heavy ion collisions**
**Special attention is needed with**
**Intra Beam Scattering**
**Rest gas ionization**
** ****Collision of different species**
**Schottky spectra are much enhanced with heavy ion "macroparticles"**

## Remote Operations

**Remote Operations is but ****one**** overlapping component of the Global Accelerator Network (GAN)**
**In ICFA, GAN is dominated by the Linear Collider enthusiasts**
**It is crucial that Remote Operations activities resist Linear Collider hegemony!  ****SNS, LHC, ...**

## Remote Operations

**Typical (sociological) question:** what gives the **remote** crew the "authority" to run a shift on the **local** accelerator?
**One answer:** **send the local "crew chief" to the remote Virtual Control Room.**
**Does this extrapolate to sending ****Dave McGinnis**** to the SL control room when ****Oliver Bruning**** et al want to participate in Fermilab PLL studies???**

## Slide 27

## http://www.agsrhichome.bnl.gov/RemOp

**http://www.agsrhichome.bnl.gov/RemOp**

## Slide 29

## Integration issues

**Lab to lab**
**Physicist to Engineer**
**Across LAPAC org chart boxes**
**With Accelerator (not Magnet) Physicists outside the 3 US labs**

## SUMMARY

**LHC IR Upgrade report (almost out!): major long term hardware  plan, again with a mix of Magnet ($$$) and Accelerator activities**
**Phase Lock Loop activities are non trivial, with the potential to integrate labs and personnel in a new way.  Eg, 4 ways to measure chromaticity.**
**The LHC has pushed some topics into the limelight:**
**Energy deposition**
**Beam loss scenarios**
**Electron cloud**

## Other fundamental topics are still with us
Beam-beam (now + strong effects, compensatio)
Nonlinear dynamics (+ SUSSIX, AC dipole, ..)
Interaction Region compensation
Relatively new topics offer exciting challenges:
Phase Lock Loops
Remote Operations
LARP Accelerator Physics is more independent of hardware development than in Phase I
Expected Level of Effort is 6+ FTEs by 2006 

**Beam-beam (now + strong effects, compensatio)**
**Nonlinear dynamics (+ SUSSIX, AC dipole, ..)**
**Interaction Region compensation**
**Relatively new topics offer exciting challenges:**
**Phase Lock Loops**
**Remote Operations**
**LARP Accelerator Physics is more independent of hardware development than in Phase I**
**Expected Level of Effort is 6+ FTEs by 2006 **