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

2. Vacuum 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.

3. F. Mazzolini Vacuum 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) (3) (4) (9) (2) (1) (10)(6)

4. F. Mazzolini Vacuum 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)

5. F. Mazzolini Vacuum 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)

6. F. Mazzolini Vacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005 Front-ends @ ELETTRA LIGHT PORTSTATUSBEAMLINES 1.1In operation/___/___Back FEL / ___ / ___ 1.2In operationFEL / NanoSpectroscopy 2.1 2.2In operationSuperESCA / ESCAMicroscopy 3.1 3.2In operationVUV Phot. / SpectroMicroscopy 4.1 4.2In operationCircularly Polarised Light 5.1 5.2In operationXRD1 / SAXS 6.1In operationSYRMEP / Materials Science 6.2In operationGas Phase / SPELEEM 7.1Under constructionMCX 7.2In operationALOISA 8.1In operationLILIT / BEAR 8.2In operationBACH 9.1In operationSISSI (Infrared) 9.2In operationAPE 10.1In operationDeep Lithography / ___ 10.2In operationIUVS / BADELPH 11.1In operationXAFS / ___ 11.2Under commissioningXRD2 12.1 12.2 (*)In operationDiagnostic 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

7. F. Mazzolini Vacuum Systems for Synchrotron Light Sources Barcelona, September 12–13 2005 Main faults# Operational consequences (for a Beamline) Bellows1Beamline out of service for 2 weeks Vacuum feedthough4 None (discovered during maintenance) None (local pressure increase) Vacuum joints~ 10None (small vacuum leaks) Vacuum valves3None (discovered during maintenance) Ion pumps1None (local pressure increase) Power supplies (vac. pumps)~ 10None (local pressure increase) Vacuum instrumentation~ 20 Wrong vacuum measurement Few e-beam dump Ancillary subsystems: cooling, pneum., electro-mechanical … ~ 50 FE not operational (~ 1 hour to recover). Few e-beam dump Front-end vacuum faults @ ELETTRA (1993 – 2004)

8. F. Mazzolini Vacuum 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?

9. F. Mazzolini Vacuum 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