Latest Developments at Daresbury Laboratory

Joe Herbert Vacuum Science Group Leader

- Daresbury Laboratory

OLAV IV April 1 – 4, 2014 – NSRRC, Hsinchu, Taiwan

Outline •Introduction (STFC; Cockcroft Institute; ASTeC)

•Activities of ASTeC (main accelerator projects) •ALICE; EMMA •VELA/CLARA •UK FEL •ELI-NP-GB

•ASTeC Vacuum Science Group R&D Highlights (general description) •NEG Coatings •SRF Coatings •SEY Studies •Photocathode development

•Topics to address during OLAV

Science and Technology Facilities Council

One of Europe’s largest multi-disciplinary

scientific research organisations

~£600 million

Joint Astronomy Centre Hawaii

Isaac Newton Group of Telescopes

La Palma Isaac Newton Group of Telescopes La Palma

UK Astronomy Technology Centre Edinburgh, Scotland

Chilbolton Observatory Stockbridge, Hampshire

Rutherford Appleton Laboratory Harwell Science and Innovation Campus Didcot, Oxfordshire

ALICE & EMMA

ASTeC & Cockcroft Institute

Old SRS Facility

VELA (CLARA)

“Its purpose is to research, design and develop particle accelerators, machines that can be used to reveal the nature of matter, to probe what happened at the instant the universe was born and to develop new materials and medicines to improve our quality of life.” – Swapan Chattopadhay (Director CI)

Significant increase in Activity in Accelerator Science and Technology in the UK (e.g. No’s of students)

Background

Centre of excellence with a flexible skill base. Play strategic role in shaping accelerator based projects in the UK (Internationally).

SRS 2001

20 Staff (now 50 + 15) RF (& Cryo) Vacuum (SS & MS) Magnets (Rad.S) Acc. Phys. Intense Beams (Lasers & Diagnostics)

ALICE & EMMA – Test Facilities (2003)

IR FEL

EMMA – FFAG

Photoinjector Laser Energy Recovery LINAC

Super Conducting RF

Beam Dump

THz Dipole Chicane

ALICE

• Grant to fund science using IRFEL & THz through Liverpool University. (Cancer)

• Demonstrate 20 um FEL output to enhance future funding opportunities.

• Use as a training facility for staff/students, e.g. LHeC test facility.

EMMA

• Understanding non-scaling FFAG

• Explore potential uses/applications (e.g. protons, muon accelerator, compact accelerators)

• Physics – Verify effects of resonance crossing.

VELA (Versatile Electron Linear Accelerator)

VELA – The Facility

VELA Beam Energy 4 - 6 MeV Bunch Charge 10 - 250 pC Bunch length (σt,rms) 1 - 10 ps Normalised emittance

1 - 4 µm

Beam size (σx,y,rms) 1 - 5 mm Energy spread (σe,rms) 1 - 5 %

Bunch repetition rate

1 - 10 Hz (with ALPHA-X gun) 1 - 400 Hz (with high rep. rate gun in the future; klystron and laser specified for 400 Hz)

£2.5 million capital investment from UK government Projects with clear IMPACT (Economic) Applications in Medicine; Health; Security; Energy Allow development of new accelerator technologies specifically through partnership with Industry. Industrial and Scientific support Required VELA, it is hoped will form the injector for CLARA (Compact Linear Advanced Research Accelerator) – Next generation particle accelerators.

Beam Energy 250 MeV Undulator Minimum

Gap 6 mm

Undulator Period 29 mm FEL Wavelength 400 – 100 nm Bunch Charge 20 – 250 pC Normalised Emittance 0.2 – 2.0 mm-mrad Seed Sources 800 nm TiSa + Mid-IR

OPA + 100 nm HHG Afterburners 50 nm Novel

Technology

CLARA

S-band RF Gun (2 ½ Cell) developed for the ALPHA-X laser-wakefield accelerator. Photoinjector uses a Cu photocathode Laser source – 400Hz amplified Ti:S laser at 800nm. Peak Intensity ~1 TW/cm^2

VELA – Industrial Interest Novel security scanning techniques

Performance testing of components for RF power delivery

Testing of novel beam position monitors

Evaluation of beam diagnostic technologies

Testing and evaluation of beam stabilisation equipment

Applications in using electron beams for industrial processes (Health & Environment e.g. Water Purification)

Shie

ld W

all

Shield Wall

Shield Wall

Electron Beam Test Facility

2m

4m

6mSh

ield

Wall

Shie

ld W

all

0m 10m

Gun

4m 6m2m 8m 12m

2.5 cell, S – band RF π-mode SWCu photocathode100 MV/m peak6 MeV

14m 16m 18m

Load – locksystem

Beam stay clear increase from φ34 mm to φ100 mm

Beam stay clear From ICT1 to YAG11minimum φ34 mm

Beam stay clearminimum φ34 mm

BPM 8 : Mechanics in placeCan be instrumented later.

~1m space required for cavity BPMsThree in a row, each with ~30 cm (Information from S. Boogert)

LaserRoom

SynchronisationRoom

NEG

Vacuum baked section

Beam stay clearminimum φ34 mm

NEG

Optical Table

Vacuum Pressure Zone 2

Vacuum Pressure Zone 1

Sputter Ion Pump (SIP)

NEG Pump

Pneumatic All metal gate valve

Inverted Magnetron Gauge (IMG)

Pirani Gauge (PIRG)

Residual Gas Analyser (RGA

Pumping Port

Key for Vacuum Symbols:

NEG

EBT-

INJ-MA

G-DI

P-01

EBT-

INJ-MA

G-QU

AD-0

1

EBT-

INJ-MA

G-QU

AD-0

2

EBT-

INJ-MA

G-QU

AD-0

3

EBT-

INJ-MA

G-QU

AD-0

4

EBT-

INJ-MA

G-QU

AD-0

7

EBT-

INJ-MA

G-QU

AD-0

8

Tran

sver

se D

efle

ctin

g Ca

vity

S -b

and

EBT-

INJ-VA

C-VA

LV-0

1

EBT-

INJ-MA

G-HC

OR-0

2/VCOR

-02

EBT-

INJ-DI

A-WC

M-01

EBT-

INJ-DI

A-HB

PM-0

1/VBPM

-01

EBT-

INJ-DI

A-YA

G-01

EBT-

INJ-MA

G-HC

OR-0

1/VCOR

-10

EBT-

INJ-MA

G-BS

OL-0

1

EBT-

INJ-MA

G-SO

L-01

EBT-

INJ-DI

A-HB

PM-0

2/VBPM

-02

EBT-

INJ-DI

A-YA

G-03

EBT-

INJ-MA

G-HC

OR-0

6/VCOR

-06

EBT-

INJ-DI

A-YA

G-05

EBT-

INJ-MA

G-HC

OR-0

4/VCOR

-04

EBT -

INJ-MA

G-HC

OR-0

3/VCOR

-03

EBT-

INJ-DI

A-YA

G-02

EBT-

INJ-VA

C-VA

LV-0

2

EBT-

INJ-MA

G-DI

P-02

EBT-

INJ-MA

G-QU

AD-1

1

EBT-

INJ-MA

G-QU

AD-1

5

EBT-

INJ-DI

A-IC

T-01

EBT-

INJ-DI

A-HB

PM-0

4/VBPM

-04

EBT-

INJ-MA

G-HC

OR-0

8/VCOR

-08

EBT-

INJ-DI

A-HB

PM-0

5/VBPM

-05

EBT-

INJ-DI

A-YA

G-08

Win

dow

EBT-

BA1-DI

A-HB

PM-0

1/VBPM

-01

EBT-

BA1-DI

A-YA

G-01

EBT-

INJ-MA

G-QU

AD-0

9

EBT-

INJ-MA

G-QU

AD-1

0

EBT-

INJ-DI

A-YA

G-06

EBT -

INJ-MA

G-HC

OR-0

7/VCOR

-07

EBT-

INJ-DI

A-YA

G-07

EBT-

INJ-MA

G-HC

OR-0

9/VCOR

-09

EBT-

INJ-VA

C-SH

UT-0

3

Tem

pora

ry V

alve

Loc

atio

n

EBT-

BA1-VA

C-VA

LV-0

1

EBT-

INJ-DI

A-IC

T-03

EBT-

INJ-DI

A-BA

M-01

LC T

est B

PM

EBT-

INJ-VA

C-SH

UT-0

2

EBT-INJ-MAG-QUAD-13

EBT-INJ-MAG-QUAD-14

EBT-INJ-DIA-YAG-09

EBT-INJ-MAG-VCOR-11

EBT-INJ-VAC-SHUT-01

EBT-BA2-DIA-YAG-01

EBT-BA2-DIA-HBPM-01/VBPM-01

EBT-BA2-VAC-VALV-01

EBT-INJ-DIA-ICT-02

EBT-INJ-DIA-HBPM-06/VBPM-06

Window

EBT-INJ-VAC-IONP-01

EBT-INJ-VAC-NEG-01

EBT-INJ-VAC-IMG-01

EBT-INJ-VAC-PIRG-01

EBT-INJ-VAC-RGA-01

EBT-INJ-VAC-IONP-03

EBT-INJ-VAC-IONP-04

EBT-INJ-VAC-IONP-05

EBT-INJ-VAC-NEG-02

EBT-INJ-VAC-IMG-02

EBT-INJ-VAC-PIRG-02

EBT-INJ-VAC-RGA-02

EBT-BA1-VAC-IONP-01

EBT-BA1-VAC-IMG-01

EBT-BA1-VAC-PIRG-01

EBT-BA1-VAC-RGA-01

EBT-BA2-VAC-IONP-01

EBT-BA2-VAC-IMG-01

EBT-BA2-VAC-PIRG-01

EBT-BA2-VAC-RGA-01

EBT-INJ-VAC-IONP-06

EBT-INJ-VAC-IONP-07

EBT-INJ-VAC-IONP-08

EBT-INJ-VAC-IONP-09

EBT-INJ-VAC-IONP-10

EBT-INJ-VAC-IONP-11

EBT-INJ-VAC-IMG-03

EBT-INJ-VAC-PIRG-03

EBT-INJ-VAC-RGA-03

EBT-INJ-VAC-IMG-04

EBT-INJ-VAC-PIRG-04

EBT-INJ-VAC-RGA-04

EBT-INJ-VAC-IMG-05

EBT-INJ-VAC-PIRG-05

EBT-INJ-VAC-RGA-05

EBT-INJ-VAC-IMG-06

EBT-INJ-VAC-PIRG-06

EBT-INJ-VAC-RGA-06

EBT-INJ-VAC-IONP-02

VELA - Schematic

VELA - Layout

Laser Transport Path – Differential Pumping System

VELA - Vacuum Requirements

• 1 x 10-10 mbar in the RF photoinjector • 5 x 10-8 mbar in the remainder of the beam transport path

• ~10-6 mbar in the laser transport system

CLARA

Why CLARA?

Dedicated Flexible FEL test facility Demonstrate advanced FEL concepts

Operating Modes

Parameter Seeding SASE Ultra-short Multibunch

Max Energy (MeV) 250 250 250 250 Macropulse Rep Rate (Hz) 1–100 1–100 1–100 1–100 Bunches/macropulse 1 1 1 16 Bunch Charge (pC) 250 250 20–100 25 Peak Current (A) Bunch length (fs)

125–400 850–250 (flat-top)

400 250 (rms)

∼1000 <25 (rms)

25 300 (rms)

Norm. Emittance (mm-mrad) rms Energy Spread (keV)

≤ 1 25

≤ 1 100

≤ 1 150

≤ 1 100

Radiator Period (mm) 27 27 27 27

CLARA CDR Parameters

UK FEL - ? (4GLS/NLS….)

• Next large scale user facility for the UK? • Significant prototyping required – CLARA • Many possible options:-

– Hard X-rays at low rep rate – Soft X-rays at high rep rate – OR a combination (multiple source)

3x Basic Accelerator Technologies

CW Superconducting RF (equi-spaced e- pulses)

Pulsed superconducting RF (non equi-spaced e- pulses, “burst mode”)

Normal conducting RF (equi-spaced e- pulses)

• There are many possibilities. • Need input from the UK FEL user community on priorities.

Key parameters determining technology and cost are: – maximum photon energy – energy per pulse – repetition rate – regularly spaced pulses or burst mode and also: – number of FELs – tuneability (energy range of each FEL) – fixed/variable polarization – attosecond schemes – seeding schemes Choice of technology will also determine how much R&D is needed and hence overall timescales …

Possible Target Parameters ? • Energy ~ 8.7 GeV • Peak photon energy ~ 18.6 keV • Gap tuneable e.g. ~ 5.5 -16.5 keV • Repetition rate ~ 100 Hz • Initial no. of FELs ~ 2 • Possible no. of FELs ~ 4+ • Length ~ 840 m • Power ~ 6.6 MW • Cost < £450m

Extreme Light Infrastructure (ELI)

Nuclear Physics (NP)

Gamma Beam (GB)

3x Co-ordinated ELI projects – Hungary (ELI – Attosecond), Czech Republic (ELI – Beamlines) and Romania (& perhaps more to come?).

ELI-NP-GB

Gamma Beam System

700 MeV high brightness e- beam, scatter intense high power optical laser photons into energetic gamma ray photons 2-20 MeV – Very High Quality Gamma Beams

Roof & Crane support steel columns

33 ELI-NP-GS Overall Accelerator & Building Layout – 3D

BPM 2 Screen 2

Ion pump

RF Acc. Structure S-band 2

(Solenoid omitted)

RF Acc. Structure C-band 1

M1 M2

M3

M4

M5

C2 C3

RF Acc. Structure S-band 1

RF Gun

Corrector 1

RF Acc. Structure S-band 1

RF Acc. Structure S-band 2

RF Acc. Structure C-band 1

QUA 01,2,3-C

SPECT-C Dipole Dump 1

M2 M3 M4 M5 Corrector 2

Laser

Solenoid coils

M1 Screen 6

Ion Pump

RF Acc. Structure C2

RF Acc. Structure C3

BPM 4 Screen 4

Ion pump

Solenoid coils

RF Gun

Screen 1 Ion pump

Current monitor 1

Corrector 3, 4 Corrector 5

Vacuum valve 2

Vacuum valve 1

BPM 3 Screen 3

Ion pump Corrector 6

BPM 5 Screen 5 Ion pump

BPM6 Ion pump

Transverse Deflecting

Cavity 1

Screen 7 Ion pump

BPM 1

Vacuum Science Group Programmes Major Work Programmes

Novel Coatings including NEG Photoinjector development SRF – Coatings SEY – Measurements (inc. morphology and surface structure effects on SEY) Vacuum System Design

Underpinning Activities Characterisation of materials for vacuum (Outgassing/Surface Analysis) Gauge Calibration (TPG & RGA/QMS) Pump Speed Measurements Cleaning/Processing Developments for UHV/XHV

NEG Developing Coating Techniques

Planar, Tubular, Complex shapes Magnetron Sputtering (PVD) Twisted wire & Alloy Wire (target for coating) CVD (plasma assisted)

Studying properties of films with different compositions. Using Ti; Zr; V; Hf (comparison of ternary and quaternary films) Using additional barrier layers e.g. Dense Aluminium, Nitrides Developing low SEY coatings e.g TiN, DLC. Reducing Activation Temperature (extends range of materials,

reduces energy consumption)

Development of Photoinjector for ALICE (complete)

Conceptual design of photoinjector for NLS/UK-FEL (complete)

Design/build upgrade ALICE gun to include load-lock wafer transfer and offline cathode activation. (Complete)

Understanding the requirements for XHV for GaAs cathode operation and the techniques to achieve XHV. (Complete)

Investigation of various cathode materials (Copper, GaAs; alkali metals) (Ongoing)

Investigating activation procedures/techniques (including fundamental understanding of surface properties) (Ongoing)

Photoinjectors

Loading chamber

Preparation chamber Surface analysis chamber

Cleaning chamber

RGA

Hydrogen cracker source

Hemispherical analyser for XPS

X-ray source

Caesium dispenser

LEED

Used to investigate surface properties of wafers under different conditions

XPS spectra of the GaAs for (a) un-cleaned sample, (b) after heating to 550° C and (c) after depositing Cs and O layers.

O1s

OKLL

Cs3d5

Cs3d3 CsMNN

Ga2p1 Ga2p3

As2p3

As2p1

(a)

(b)

(c)

3-Stage Loadlock Vacuum & Transfer Wafer Replacement System Wafer replacement time reduced from ~1 month to ~30 min

Metal Photocathodes - Highlights

• Surface preparation of variety metal photocathodes to be used in an RF Gun ( Cu, Ag, Mg, Ti, Pb, Zr, Nb).

• Determination of QE, Work Function and Transverse Energy Spread for different Bulk metals ( single crystal and polycrystalline) and thin metal film as a function of surface preparation, surface chemical state and residual gas absorbate.

• Theoretical modelling of photoemission and validation of calculations using experimental data.

Surface Science Facilities

SRF Thin Films- Highlights • PVD and ALD deposition of SRF thin film ( Nb, NbN and

NbNC) on flat surfaces and 3D structures.

• Study of SRF properties and Microstructure of the film as function of deposition parameters.

• Study of Superconducting properties of these films such as RRR, Hc, AC susceptibility.

• More than 40 Nb samples with RRR ranging from 3 to 30 has been deposited so far.

SRF-Films

Last 2 slides - OLAV IV

OLAV IV

• ELI – NP Project – Ion Pump PSU as TPG – Experience with VACOM, EVAC and Slotted

CF flanges (where space is restricted) – Contamination risk from mobile vacuum

diagnostic systems (rather than permanent) – Extended Warranty Options (vacuum

equipment)

Special Issue ‘VACUUM’ –OLAV? • Oleg Malyshev (ASTeC)

– Associate editor of journal ‘Vacuum’ – Tasked specifically to develop ‘Special Issues’. – Suggested Topic - OLAV – Literature doesn’t contain Operational Wisdom. – Is there a desire to document significant

learning/experience/wisdom? – A few volunteers to coordinate articles (perhaps

3 - US, Asia, Europe)

ASTeC activation procedure

O.B. Malyshev, K.J. Middleman, J.S. Colligon and R. Valizadeh. J. Vac. Sci. Technol. A 27 (2009), p. 321.