# Presentation: 664405

## AC Dipole and it applications

**Ryoichi Miyamoto, UT Austin**
**Mei Bai, C-A Department, BNL**

- Andreas Jansson (FNAL), Mike Syphers (FNAL), Sacha Kopp (UT, Austin), Rama Calaga (BNL), Wolfram Fischer (BNL), Hermann Schmickler (CERN), Javier Serrano (CERN)

## Outline

- Introduction of ac dipole
-  comparison of ac dipole systems
- Tevatron, RHIC, LHC
-  highlights of what have been done
-  AC dipole for LHC Collaboration

## Introduction of ac dipole

- Long lasting large coherent oscillation with emittance preserved

## Applications of AC dipole

- Linear optics measurement
- Measure beta function and phase advance
- Measure beta function at interaction point
- Linear coupling measurement
- Local coupling measurement
- Non-linear driving term measurement
- Dynamic aperture measurement
- Spin manipulation

## Parameters of the RHIC,Tevatron, and LHC

| machine(GeV) | RHIC(250) | Tev (150) | Tev (980) | LHC(7000) |
| --- | --- | --- | --- | --- |
| frev [kHz] | 78 | 47.7 | 47.7 | 11 |
| ν, 1-ν | 0.71 | 0.58, 0.42 | 0.58, 0.42 | 0.3, 0.7 |
| fm [kHz] | 55 | 20 | 20 | 3, 8,14,19 |
| (Bρ) [Tm] | 833.9 | 500 | 3,300 | 23,000 |
| δ | ≥ 0.01 | ≥ 0.01 | ≥ 0.01 | ≥ 0.01 |
| β (βm) [m] | 45(11) | 80 (47) | 80 (47) | 180 |
| σ [mm] | 0.75 | 1.3 | 0.5 | 0.3 |
| BmL [Gm] (4σ)  | 142 | 50 | 140 | 190 |
| IFNAL [A] | 284 | 100 | 280 | 380 |
| BmL [Gm] | 100 | 50 | -- | -- |

## AC dipole systems at Tevatron and RHIC

## II-1. The Magnet and Power Supply

**30ms**

**30ms**

**80ms**

**Input *****V***

***V***** in CT**

***8.5***** V (*****85***** A)**

***2***** m**

**E17 Vertical Pinger**

***I******max***** ≈ *****100***** A**

***B******m******L***** ≈ *****50***** Gm**

- Waveform
- Generators

- (Audio)
- Amplifier

***5***** V**

*B**m**L ≈ 0.5 I**magnet** *Gm

## II-2. AC Dipole as a Parallel Resonant Circuit

***2.5*****μ****H**

***6*****μ****F**

***65*****m****Ω**

***8.3*****μ****H**

***8.2*****μ****F**

- Power Supply

- Magnet + Cables

***20*****kHz**

**CT**

- Schematic Diagram and Picture of the Circuit

***Z******tot ******≈****** 10 *****Ω**

***R+X******L ******=****** ******1 *****Ω**

*I**magnet* = *V**amp* */* (*R+X**L*)
-           ***≈*** *100* A

- The Parallel Capacitor
-  increases the total impedance
-  keeping the *I**amp* low.

## II-6. β Measurement 

**B0**

**D0**

- _II-3. TBT BPM Data_

- 150GeV
- Uncoalesced, Single Bunch
*B**m**L = 80 Gm*,* **δ* = 0.01
*β**y* = 130 m, *β**m* = 47 m
- Should be *5 *mm but *3* mm ??
- Coupling? Magnet?

**V**

**H**

## RHIC AC dipole system

- Magnet
- Air core with Litz wire
- Ceramic beam pipe with an dimension of
- Two aluminum strips outside the beampipe provide a path for image current
- Location

## RHIC AC dipole system

- Inductance of the magnet:
- In parellel: 26.362 uH
- In series: 104.32 uH

- Current achieved
- In series: 50 Amp ~ 67 Gm
- In parallel: 160 Amp ~ 106 Gm

- Proton beam at 100 GeV

## Beta function and phase advance measurement in RHIC

| IP | 2 | 4 | 6 | 8 | 10 | 12 |
| --- | --- | --- | --- | --- | --- | --- |
| Average | 1.884
±0.051 | 4.858
±0.0034 | 0.883
±0.011 | 1.000
±0.0097 | 2.527
±0.0095 | 5.924
±0.125 |
| design | 2.0 | 5.0 | 0.85 | 0.85 | 3.0 | 5.0 |

## Objective

Investigate the conceptual design of ac dipole for LHC
System design
Magnet design
Power system design
Explore new technologies to achieve broad tuning range
test system 
the principles either at Tevatron or RHIC. 
the technology applicable to LHC
Physics motivations and relevant beam experiments at RHIC and Tevatron 

Financing
LARP: R&D
CERN: Final systems, funding available earliest at 2008
NSF through university program

- Investigate the conceptual design of ac dipole for LHC
- System design
- Magnet design
- Power system design
- Explore new technologies to achieve broad tuning range
- test system
- the principles either at Tevatron or RHIC.
- the technology applicable to LHC
- Physics motivations and relevant beam experiments at RHIC and Tevatron
- Financing
- LARP: R&D
- CERN: Final systems, funding available earliest at 2008
- NSF through university program

- AC dipole collaboration

## Team
FNAL, Univ. Texas, Austin, BNL, CERN

Deliverables
conceptual design report
Test system(s)
Relevant beam studies at Tevatron and RHIC

- FNAL, Univ. Texas, Austin, BNL, CERN
- Deliverables
- conceptual design report
- Test system(s)
- Relevant beam studies at Tevatron and RHIC

- AC dipole collaboration