Diamond Light Source Vacuum Systems

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Diamond Light SourceVacuum Systems

• Matthew Cox
• matthew.cox_at_diamond.ac.uk

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What is Diamond?

• 3rd generation 3 GeV synchrotron light source
• Currently under construction near Oxford, UK
• First user beam planned for 2007
• Constructed and operated by Joint Venture Company
  (Diamond Light Source Ltd) between UK Government
  represented by CCLRC (86) and Wellcome Trust
  (14)
• 7 phase one beamlines increasing by 4-5 per year
  (maximum around 40 beamlines)
• Optimised to produce high intensity focused
  x-rays from 100 eV to 100 keV for research in
  physics, chemistry, materials science and
  crystallography

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Diamond main parameters

• 3 GeV 300 mA (later 500 mA)
• 24-cell Double Bend Achromat (DBA) design (48
  dipole magnets)
• 6-fold symmetry
• 18 x 5.3 m straights
• 6 x 8.3 m straights (4 available for IDs)
• Emittance (H,V) 2.7, 0.03 nm rad
• Lifetime 10 20 hours

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Diamond vacuum systems
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Diamond layout
Storage ring
Linac
Aerial photo 04 June 04
Beamlines
Booster
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Storage ring overview

• 24 identical arcs (17.35 m) each containing
• 2 bending (dipole) magnets numerous quadrupole
  and sextupole magnets
• 2 crotches (x-ray beam outlets to front ends and
  beamlines)
• No in-situ bakeout (except for ion pumps)
• Assembled, processed and installed on 3 girders
• 24 straights
• 18 short (5.3 m) ID straights
• 6 long (8.3 m) straights (Injection, RF,
  Diagnostics)
• In-situ bakeout generally
• Total circumference 561.6 m

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Storage ring arc
Front end isolation valve
Front end isolation valve
Dipole
Sector isolation valve
Sector isolation valve
Dipole
17.35 m long Assembled, processed and installed
in 3 sections
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Storage ring arc pumping and instrumentation

• Differential (noble) diode ion pump (16)
• NEG cartridge pump (2)
• TSP (2)
• All-metal gate valves (4) of which 2 have RF
  liner
• All-metal right-angle valves (4)
• Inverted magnetron / Pirani gauge pair (4)
• RGA (2)
• Roughing by mobile turbo/scroll pump cart

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Storage ring materials and processing

• Target pressure 10-9 mbar with full stored
  current after 100 A.h of beam conditioning
• Mainly 316 LN stainless steel with 316 L in less
  critical places
• Out-of-vacuum ID vessels extruded aluminium with
  NEG coating
• Mixture of distributed and discrete copper
  absorbers
• No antechamber
• No in-situ bakeout for storage ring arcs except
  for ion pumps
• Pre-installation bakeout to 200-250C
• Nitrogen venting and purging with pre-baked
  components for minor interventions
• Whole sector removed for major interventions
• Spare processed sector on standby
• In-situ bakeout for straights and front ends

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Dipole and crotch vessel assembly
e-beam channel
Bellows with RF assembly
Crotch absorber port
Pumping port
e-beam direction
X-ray beam channel
Total 48 assemblies 3.5/3.8 m long 2 crotch
vessel variants
Finger absorber port
Rectangular Conflat joint
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Photon absorbers
Discrete crotch and finger absorbers, OFHC copper
vacuum brazed
Explosion bonded OFHC copper distributed absorber
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Storage ring vacuum assembly and installation
Integrate with girders, magnets and services
Vessels cleaned and baked to 250C at suppliers
Transport up to 16 tonne girders 1000 m to
synchrotron building
6 m vacuum string assembly and pre-alignment on
trolleys
Crane into final position through the SR tunnel
roof
Pump down and leak test
Lift into oven
Vent to dry nitrogen, make vacuum
interconnections to straights and pump down
Repeat 71 times
Bakeout to 200-250C
Bake straights in situ as needed
Lift under vacuum to Girder Assembly area
Vacuum conditioning with stored beam
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Storage ring assembly and installation
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Injection system
Part of LTB transfer line assembled on site from
vessels
Turnkey Linac system
Pre-baked booster vacuum vessel and ion pump
supplied under vacuum as part of girder assembly
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Front ends

• 3 main designs of front end
• Undulator (6 phase one)
• Superconducting multipole wiggler (1 phase one)
• Bending magnet
• Procured as complete assemblies baked and vacuum
  tested

Absorbers for the undulator front ends
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Beamlines and insertion devices

• 7 phase one beamlines
• Macromolecular crystallography x 3
• Extreme Conditions
• Materials and Magnetism
• Microfocus Spectroscopy
• Nanoscience (UHV)
• 7 phase one insertion devices
• 5 in-vacuum undulators
• 1 out-of-vacuum undulator
• 1 superconducting multipole wiggler

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Installation and commissioning status
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Acknowledgements

• Diamond Vacuum Group
• ASTeC Vacuum Science Group
• Diamond Project Team