# Presentation: 694677

## 

Philip Burrows

John Adams Institute, Oxford University

Overview of intra-train feedback system
FONT2 (NLCTA) results (2004)
FONT3 (ATF) system + results (2005)
FONT4 digital system for ILC
EM background tests

**Philip Burrows**
***John Adams Institute, Oxford University***
**Overview of intra-train feedback system**
**FONT2 (NLCTA) results (2004)**
**FONT3 (ATF) system + results (2005)**
**FONT4 digital system for ILC**
**EM background tests**

**Overview of Fast Feedback Hardware R&D**

## FONT: 
		Queen Mary: Philip Burrows, Glen White, Glenn Christian,
		  Hamid Dabiri Khah, Tony Hartin, Stephen Molloy, 
		  Christine Clarke, Christina Swinson
		Daresbury Lab: Alexander Kalinin, Roy Barlow, Mike Dufau 
		Oxford: Colin Perry, Gerald Myatt
		SLAC: Joe Frisch, Tom Markiewicz, Marc Ross, Chris Adolphsen,  		  Keith Jobe, Doug McCormick, Janice Nelson, Tonee Smith, 		  Steve Smith, Andrei Seryi, Mark Woodley, Linda Hendrickson.	

FEATHER: 
		KEK: Toshiaki Tauchi, Hitoshi Hayano
		Tokyo Met. University: Takayuki Sumiyoshi, Hiroaki Fujimoto

Simulations: Nick Walker (DESY), Daniel Schulte (CERN)

Eurotev (BDS, ILPS),    ELAN (Instr, Bdyn),    ILC WG4 (BDS)

**	****	****Queen Mary: Philip Burrows, Glen White, Glenn Christian,**
**	****	****  *****Hamid Dabiri Khah*****, Tony Hartin, Stephen Molloy, **
**	****	****  ****Christine Clarke, *****Christina Swinson***
**	****	****Daresbury Lab: Alexander Kalinin, Roy Barlow, Mike Dufau **
**	****	****Oxford: Colin Perry, Gerald Myatt**
**	****	****SLAC: Joe Frisch, Tom Markiewicz, Marc Ross, Chris Adolphsen,  ****	****	****  Keith Jobe, Doug McCormick, Janice Nelson, Tonee Smith, ****	****	****  Steve Smith, Andrei Seryi, Mark Woodley, Linda Hendrickson.****	**
**FEATHER: **
**	****	****KEK: Toshiaki Tauchi, Hitoshi Hayano**
**	****	****Tokyo Met. University: Takayuki Sumiyoshi, Hiroaki Fujimoto**
**Simulations: ****Nick Walker (DESY), Daniel Schulte (CERN)**
**Eurotev (BDS, ILPS),    ELAN (Instr, Bdyn),    ILC WG4 (BDS)**

**International Fast FB Collaboration**

## Intra-train Beam-based Feedback Concept

**Intra-train beam feedback is last line of defence against relative beam misalignment**
**Key components:**
**Beam position monitor (BPM)**
**Signal processor**
**Fast driver amplifier **
**E.M. kicker**
**Fast FB circuit**

**TESLA TDR:   principal IR**
**beam-misalignment correction**

## ‘Large’ crossing angle (NLC)

**FB BPM**

**kicker**

## Zero-degree crossing angle (TESLA TDR)

**FB BPM**

**Upstream **
**kicker(s)**

## Aim: prototype components required for ILC intra-train beam feedback system(s):

		BPMs
		Signal processor
		Feedback circuit
		Amplifier
		Kicker 

and demonstrate system performance with real beam

**	****	**
**	****	****BPMs**
**	****	****Signal processor**
**	****	****Feedback circuit**
**	****	****Amplifier**
**	****	****Kicker **
**and demonstrate ****system**** performance with ****real beam**

**Feedback Hardware Program Goals****(FONT/FEATHER)**

## NLCTA: 65 MeV beam, 170ns train, 87ps bunch spacing

FONT1 (2001-2):
	First demonstration of closed-loop FB: latency 67ns
		10/1 beam position correction

FONT2 (2003-4):
	Improved demonstration of FB: latency 54ns
		real time charge normalisation with logarithmic amplifiers
		beam flattener to straighten train profile
		solid-state amplifier

ATF: 1.3 GeV beam, 56ns train, 2.8ns bunch spacing

FONT3 (2004-5):
	Ultra-fast demonstration of FB: latency 23 ns
		3 stripline BPMs 
		high-power solid-state amplifier

**FONT1 (2001-2):**
**	****First demonstration of closed-loop FB: latency 67ns**
**	****	****10/1 beam position correction**
**FONT2 (2003-4):**
**	****Improved demonstration of FB: latency 54ns**
**	****	****real time charge normalisation with logarithmic amplifiers**
**	****	****beam flattener to straighten train profile**
**	****	****solid-state amplifier**
**ATF: 1.3 GeV beam, 56ns train, 2.8ns bunch spacing**
**FONT3 (2004-5):**
**	****Ultra-fast demonstration of FB: latency 23 ns**
**	****	****3 stripline BPMs **
**	****	****high-power solid-state amplifier**

**FONT Prototype Intra-train ****Analogue Feedback Systems**

## FONT2 beamline installation at SLAC NLCTA(65 MeV 170ns-long train @ 87ns spacing)

**Dipole and kickers**

**New BPMs**

## FONT2 results: feedback BPM

**Feedback on**

**Beam flattener on**

**Beam starting positions**

**Delay loop on**

**beam start**

**beam end**

**1**

**2**

**3**

**4**

## FONT: kicker driver amplifiers

**FONT1 3-stage tube amplifier**

**FONT3 PCB**
**amplifer + FB**

**Same drive power**
**as needed for ILC**

## FONT3 outline

**Adjustable-gap **
**kicker**

**BPM **
**ML11X**

**Feedback**

**Superfast**
**BPM processor**

**Superfast**
**amplifier**

**BPM **
**ML12X**

**BPM **
**ML13X**

**Aim: **
**TOTAL latency**
** ****< 20 ns**

## FONT3: BPM processor + amplifier/feedback installation in ATF beamline

**BPM processor board**

**Amplifier/FB board**

**FEATHER**
**kicker**

## FONT3: latency budget

**Time of flight kicker – BPM: ****	****	****          4ns**
**Signal return time BPM – kicker:              6ns**
**	****	****Irreducible latency:                                     10ns**
**BPM processor:                                         5ns**
**Amplifier + FB:                                           5ns**
**	****	****Electronics latency:                                    10ns**
**Total latency budget:                                        20ns**
**Will allow  56/20  =  2.8  periods during bunchtrain**

## FONT3: BPM processor tests (single-bunch, December 2004 beam tests)

## FONT3: BPM processor latency measurement  (single bunch, March 17 2005 beam tests)

**raw signal**

**processor output**

**Distribution of latency:**

**latency**

**Latency 4.7 ns **

## FONT3: BPM scale calibration using correctors (20-bunch data, March 17 2005 beam tests)

**BPM11**

**BPM12**

**BPM13**

## FONT3: BPM position resolution (20-bunch data, March 17 2005 beam tests)

**Distributions of residuals (240 beam pulses):**

**BPM11**

**BPM12**

**BPM13**

**Resolution: 3 - 5 um**

## FONT3: Beamline Installation

## FONT3: Results (June 3 2005)40 pulses per position setting

## FONT3: Results (June 3 2005):Delay-loop feedback w. latency 23 ns

**56ns bunchtrain**

**FB on**

**FB + delay loop on**

**23ns**

**200um**

## FONT3: Averaged results (HIGH gain, nominal delay settings)

## FONT3: Averaged results (LOW gain, nominal delay settings)

## FONT3: Average results (variation of delay-loop settings)

**Delay loop length**

**Delay loop gain**

## Demonstrated feedback with delay loop

Ultra-fast system: total latency 23 ns

Varied main gain, delay loop length, delay loop gain
system behaves as expected

Beam quality + limited time (6 shifts) did not allow detailed optimisation of system parameters

**Ultra-fast system: total latency 23 ns**
**Varied main gain, delay loop length, delay loop gain**
**system behaves as expected**
**Beam quality + limited time (6 shifts) did not allow detailed optimisation of system parameters**

**FONT3: Summary**

## FONT1,2,3: Summary

**67 ns**

**54 ns**

**23 ns**

**Even fast enough for **
**CLIC intra-train FB!**

## ATF/(ATF2): 1.3 GeV beam, 3 bunches with spacing c. 150ns

FONT4 (2005-6):
	modified FONT3 BPM front-end signal processor 
	digital FB system
	modified FONT2 solid-state amplifier: 300ns long o/p pulse
	FEATHER adjustable-gap kicker

 Aiming for first demonstration of FB w. ILC-like bunches: 
	total latency 140ns (electronics + signal propagation)
	stabilisation of 3rd bunch at um level

First component tests at ATF December 2005/April 2006

**FONT4 (2005-6):**
**	****modified FONT3 BPM front-end signal processor **
**	****digital ****FB system**
**	****modified FONT2**** ****solid-state amplifier: 300ns long o/p pulse**
**	****FEATHER adjustable-gap kicker**
** ****Aiming for first demonstration of FB w. ILC-like bunches: **
**	****total latency 140ns (electronics + signal propagation)**
**	****stabilisation of 3****rd**** bunch at um level**
**First component tests at ATF December 2005/April 2006**

**FONT4: Prototype Digital Feedback System**

##  FONT4: Digital FB Processor Module (Dabiri Khah)

- FPGA

- DAC

- DAC

- ADC

- ADC

- ADC

- ADC

- Differential
- To
- single

- RAM

- Clock
- circuit

- JTAG
- circuit

- USB
- circuit

- UART
- circuit

- IN Power
- Jack & switch

- 5v

- 2.5v

- ? v

- 3.3v

- JTAG
- connector

- Serial
- connector

- USB
- connector

- Flash/
- EEPROM

- Differential
- To
- single

- Differential
- To
- single

- Differential
- To
- single

** ****FONT4: Digital FB Processor Module (Dabiri Khah)**

**Latency goal 100ns**

## 1. FONT4 prototype ILC digital FB system 
	Dec 05: modified analogue BPM processor tests
	Apr 06: test of digital FB board 
	Jun 06: closed-loop FB system test with 3-bunch train

2. Ring -> extraction-line feed-forward 
	Dec 05: jitter correlations + transfer matrix studies
	2006:    design + tests of feed-forward system

3. FONT5 prototype ILC digital FB system
	2007: algorithm development + tests w. 20-bunch train

**	****Dec 05:**** modified analogue BPM processor tests**
**	****Apr 06:**** test of digital FB board **
**	****Jun 06:**** closed-loop FB system test with 3-bunch train**
**2. ****Ring -> extraction-line feed-forward**** **
**	****Dec 05:**** jitter correlations + transfer matrix studies**
**	****2006:****    design + tests of feed-forward system**
**3. ****FONT5 prototype ILC digital FB system**
**	****2007:**** algorithm development + tests w. 20-bunch train**

**FONT plans for ATF/ATF2**

## Background Environment for FB BPM (20 mrad)(Hartin)

**Investigated:**
**BPM z location**
**EXT1 position**
**Azimuthal effects**
**L* + Detector B-field**

## Background further down extraction line (20 mrad)

**Will be done for **
**2 mrad scheme also**

## Dependence on Machine Parameter Set 

**# primary pairs/ bunch Xing**

## ESA: 30 GeV beam, single bunch

BPM survivability tests (2006-7):
	put beam through radiator in beam switchyard
	produce ‘spray beam’ to model ILC primary e+e- flux
	mechanical mockup of forward material in ILC IR
	showering -> secondary e+e- and gammas
	irradiate BPM in realistic environment, study:
		noise on direct beam signals
		long-term BPM stability and performance

**BPM survivability tests (2006-7):**
**	****put beam through radiator in beam switchyard**
**	****produce ‘spray beam’ to model ILC primary e+e- flux**
**	****mechanical mockup of forward material in ILC IR**
**	****showering -> secondary e+e- and gammas**
**	****irradiate BPM in realistic environment, study:**
**	****	****noise on direct beam signals**
**	****	****long-term BPM stability and performance**

**FONT@ESA**

## Spray Beam Characteristics(Christian)

- Output of simulation shows range of energies between 0 and 30GeV

## Intra-train feedback performance (TESLA)(White)

**y position FB:**
**restore collisions**
**within 100 bunches**

**1 seed:**
**post-BBA**
**+ GM**
**+ wakes**

**y position scan:**
**optimise signal **
**in pair monitor **

**y angle scan**

**OPTIMAL**
**LUMINOSITY**

## ILC IR-1 (20mrad crossing angle) BDS Results(White)

**Effect of luminosity feedback:**

**Position and angle**
**scan recovers**
**13% more lumi!**
**Fast lumi meas. **
**from BEAMCAL**
**important**
**(Grah et al)**

## BeamStrahlung (White)

**ILC IR**

**BeamCal**

**Photon Detector**

- 200m

**BeamStrahlung ****(White)**

**Diagnostics of bunches at IP.**
**3 potential sources of information:**
**Energy-distribution of Pairs.**
**Number-distribution of Pairs.**
**Energy-distribution of Photons.**