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BNL LARP Accelerator Physics Program

ResourcesBNL role in national program

BNL Accelerator Physics Program

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LARP FY06 Program Resources

36% ($4.0M) of funding goes to Accelerator Systems:- Beam diagnostics instrumentation- Accelerator Physics theory, simulations & expts- Commissioning- Collimation

52% ($5.7M) goes to Superconducting Magnet R&D - Goal oriented: first LHC Interaction Region upgrade- Limited funding allows only a narrow scope

Nb3Sn quadrupoles (necessary in all scenarios)First IR upgrade onlyNo IR dipoles, fast cycling magnets, magnetic TAN, ...Minimal synergy other programs (ITER, ...)

- No construction!

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BNL role in the LARP Accelerator Physics Program

Electron cloud Drees, He, ..

Beam-Beam wires Fischer, post-doc, ..

IR Comm. Wanderer, ..

Beam Comm. Calaga, Drees, ..

Tune feedback CAMERON, ..

Lumimonitor Drees

Schottky Cameron

Cleaning Eff. Studies DREES, ..

Irradiation studies SIMOS, ..

BNL names in blue, task leaders UPPER CASE

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BNL LARP Accelerator Physics Program - strong role of RHIC

The RHIC complex is a major accelerator facility. In a few years it will be the only US high energy hadron collider and, together with the LHC, one of two in the world. This produces a significant degree of synergy with the LHC.

Numerous beam dynamics issues are under study both within LARP and external to LARP.

– PLL tune & coupling feedback (real time coupling signal)– Beam-Beam (present proton limit, strong-strong like LHC)

• Long range beam-beam compensation (with wires)• Head on beam-beam compensation (with an electron lens)

– E-cloud studies (present heavy ion limit)– Non linear IR corrections – HI collimation and beam loss studies

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Phobos magnet

IP

5m

TWC

Warm Dipoles Electron Detector

Sec 10

Sec 9

Existing concrete stands

LHC type electron detectors in IR10 for detailed e-cloud studies

• study e-cloud formation with and w/o dipole field

• much higher sensitivity than the RHIC type detectors

• focus on surviving electrons in gaps and fill pattern optimization

• approved for APEX time during this run in FY06 (polarized protons)

• collaboration BNL (A. Drees, D. Hseuh et al. ) and CERN (M. Jimenez et al.)

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Bound-free Pair Production (BFPP) Measurement at RHIC

Ions after e-capture can cause a “hot-spot” at a location downstream of the IR => potential problem at the LHC First attempt to measure the cross section at RHIC (A. Drees, W.

Fischer, J. Jowett et al.)

count rate @ local loss monitor when collisions start cross section measurement

using vernier scan technique:BFPP = 0.97 mb (prelim.)(pred.: 0.15 mb)

IR

point of impact simulation

~ 8 Hz

7-100 -50 0 50 100 150 200 250 300

0

0.5

1

1.5

2

2.5

3

3.5

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Log of losses (arb. units)

distance from PHENIX (m)

Comparison ICOSIM (black) with BLM data during gap cleaning

PHENIX

PHOBOS

12 o'clock

BRAHMS

4 o'clock

STAR

Loss Maps and Luminosity Monitors• fast and rad. hard LHC type luminosity monitor

(ionization chamber) is installed in IR10• collaboration between BNL and LBNL (A. Ratti et

al.), approved for APEX time this year • 1st use “in the field” this year in RHIC,

calibration with existing luminosity detectors (ZDCs).

• Loss maps for HI and protons (code benchmarking)• collaboration between BNL (A. Drees) and CERN (R.

Assmann et al., H. Braun et al.)

1st attempt to predict loss maps for HI in RHIC (and later LHC) and to compare with data

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BNL LARP Accelerator Physics Program

LHC will be very vulnerable to transients in the energy ramp

NEED FEEDBACK for

- closed orbits (CERN)

- tune (LARP)

- chromaticity (LARP)

Recent results from RHIC show “military precision” in maintaining desired tunes

Tune & coupling feedback system (4 variables) shows collaborative benefits to all:

BNL + CERN + FNAL

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BNL LARP Accelerator Physics Program

Decoupling success

Coupling feedback allows UNPRECEDENTED proximity of the two tunes (0.0007 at left)

The crux has been passed (?) in the quest for chromaticity feedback.

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BNL LARP Accelerator Physics Program

LARP AP is and will continue to be an effective mechanism to provide US expertise towards supporting the LHC program

BNL personnel are playing a major role in this process. Many on-going collaborations with CERN and the other US labs

RHIC is able to provide a developmental environment for many LHC sub-systems without the problems of start-up conditions