Status of the AC Dipole Studies

Ryoichi Miyamoto (UT Austin)

LARP Meeting at FNAL 9/12/2007

LHC AC dipoles will be the Tevatron style.

Machine RHIC Tevatron LHC

E [GeV] 250 980 7000

frev [kHz] 78 48 11

ν, 1- ν 0.69, 0.31 0.58, 0.42 0.3, 0.7

fd [kHz] 55 20.5 3, 8,…

δ ≥ 0.01 ≥ 0.01 ≥ 0.01

βarc , βd [m] 45, 11 80, 47 180, 260

σ [mm] 0.75 0.5 0.3

Bdl [Gm] (4σ) 140 140 165• RHIC AC dipole system: air core magnet + custom made amplifier• Tevatron AC dipole system: already installed (iron core) pinger + audio amplifier

Requirement to the Power Supplyto Produce 4σ Oscillation @ the Collision Energy

Tevatron AC Dipole LHC AC Dipole

Imagnet [A] 450 1700

Rmagnet+calbe [mΩ] 85 11

P=I2R/2 [kW] 8 16

Pdesign [kW] Pmagnet [kW] Imagnet [A]

Crown I-T8000 8 4.5 320

LabGruppen FP13000 13 4.5 320

2 Crowns 16 6.5 390

2 LabGruppens 26

Results of the Power Supply Tests

−

−

+

+

NP NS

NP

ZL ~ 10 Ω

Schematic Diagram ofthe Dual Amplifier System

Potential Issues

• Burst length?• An audio amplifiers doesn’t like resonant circuits?• Transformer?

Power to produce 200 A

Lossy Core!

An AC dipole has an influence like a thin quad.

δ = νd - ν

Measured Phase Space @ B0 IP

true β δ = -0.01 δ = -0.02 Beam motion is still given by

));(cos();()()( dd ssAsx

Change of β is the same as a thin quad:

acdacd

d 4

)2sin(

)2cos()2cos(2

q

Vertical β for New Proton and Pbar HeliciesProton Helix

Pbar Helix

βv,B0 = 27.9 cmβv,D0 = 30.8 cm

βv,B0 = 35.9 cmβv,D0 = 36.2 cm