F. Mazzolini Vacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005 Front-end vacuum system F.Mazzolini.

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

Front-end vacuum system

F.Mazzolini

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

A Front-End is the interface between the Storage Ring and one or more Beamlines. It includes all the components installed between a Light Port in the Storage Ring and the first optical element of the connected Beamline. It should:

• protect the personnel from accidental exposure to high-energy ionising beams or to the intense beam of synchrotron light;

• protect the vacuum of the storage ring (contamination and/or air inrush from the Beamline);

• protect the optical components of the beamline from possible contaminants (from the SR);

• dissipate all the unusable power generated from the light source in order to reduce the overheating of the BL optical components.

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

ID Front-end layout (ELETTRA)

- Undulator section 8 -

1) Diaphragm

2) Photon Shutter

3) Beam Stopper

4) Fast Valve

5) IMG

6) IMG + Pirani

7) RGA

8) Gate Valve

9) Ion Pump

10) Delay Line

11) (Double Slits)

12) (Photon BPM)

13) Shielding Wall

(13) (7)(5) (8)(9)(9) (3)(4)(9)(2)(1) (10)(6)

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

BM Front-end layout (ELETTRA)

1) Diaphragm (2 x 6mrad)

2) Photon Shutter + Beam Stopper

3) Gate Valve

4) Fast Valve

5) IMG + Pirani

6) RGA

7) Ion Pump

(1) (2)(5) (3) (4) (6)(7)

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

Insertion Device Front-end Bending Magnet Front-end

The Front-end Vacuum System @ ELETTRA

Length: 6 m

IMG: 2

Pirani gauge: 1

Ion pump 230 l/s: 3

NEG Pump: 3

P < 1 E-9 mbar (with photons)

Length: 11 m

IMG: 5

Pirani gauge: 3

Ion Pump 230 l/s: 5

NEG Pump: 1

P < 1 E-9 mbar (with photons)

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

Front-ends @ ELETTRALIGHT PORT STATUS BEAMLINES

1.1 In operation/___/___ Back FEL / ___ / ___1.2 In operation FEL / NanoSpectroscopy2.12.2 In operation SuperESCA / ESCAMicroscopy3.13.2 In operation VUV Phot. / SpectroMicroscopy4.14.2 In operation Circularly Polarised Light5.15.2 In operation XRD1 / SAXS6.1 In operation SYRMEP / Materials Science6.2 In operation Gas Phase / SPELEEM7.1 Under construction MCX7.2 In operation ALOISA8.1 In operation LILIT / BEAR8.2 In operation BACH9.1 In operation SISSI (Infrared)9.2 In operation APE

10.1 In operation Deep Lithography / ___10.2 In operation IUVS / BADELPH11.1 In operation XAFS / ___11.2 Under commissioning XRD212.1

12.2 (*) In operation Diagnostic

Light Port = m.n

m = straight section number

m = 1 ÷ 12

n = light source type

n = 1 Bending Magnet n = 2 Insertion Device

(*) 12.2 Bend. Magnet

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

Main faults #Operational consequences

(for a Beamline)

Bellows 1 Beamline out of service for 2 weeks

Vacuum feedthough 4None (discovered during maintenance)None (local pressure increase)

Vacuum joints ~ 10 None (small vacuum leaks)

Vacuum valves 3 None (discovered during maintenance)

Ion pumps 1 None (local pressure increase)

Power supplies (vac. pumps) ~ 10 None (local pressure increase)

Vacuum instrumentation ~ 20Wrong vacuum measurementFew e-beam dump

Ancillary subsystems: cooling,pneum., electro-mechanical …

~ 50FE not operational (~ 1 hour to recover).Few e-beam dump

Front-end vacuum faults @ ELETTRA (1993 – 2004)

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

Front-end vacuum system: few (silly?) questions.

Pumping system

Ion pump: diode, triode, Ti-Ta, Starcell are really so different?

Getter pump: TSP, Neg cartridge or coating. Do we need them?

Fast valve system

It works, but it is expensive! Can we serenely live without it?

Vacuum Instrumentation

IMG, RGA: where do we have to install them?

RGA: vacuum monitoring or just for maintenance?

Ancillary subsystem

Water flowmeters, position indicators (microswitches), thermocouples, etc. are potentially “dangerous”! Possible effects on the interlock system

(Beam dump!). Which strategies to reduce their impact on the accelerator operations?

Reliability

Do you adopt any systematic preventive maintenance (bellows, ...)?

Generally speaking

Accordingly with your experience, which are the weakest point (if any) in a really used Front-end?

F. MazzoliniVacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005

Some facts:

• 20 fast valves installed on 16 front-ends (VAT 77, CF40-CF160)

• 1 front-end without fast valve (Infrared beamline)

• 5 ventings of the storage ring (SR) avoided in 12 years

• 0 spurious closing (no sensor installed in the SR)

• ~300 k€ spent in 9 years (1993 – 2001)

• 10 full days to recover from a complete venting of the SR (minimum!)

• 21 different experiments at the same time

• ~50 users/day

Fast valves @ ELETTRA