G' Y' Hsiung 1

1
NSRRC Vacuum System and the Conceptual Design for
the Taiwan Photon Source Vacuum System
Workshop on Vacuum Systems for Synchrotron Light
Sources, Barcelona, SPAIN, 12 -13 Sep. 2005.
Gao-Yu Hsiung (???) Vacuum Group
2
Taiwan Light Source (TLS)
VUV
SX
HX
ID in operation W20 (1995) 4 15 keV U10
(1995) 3 500 eV U5 (1997) 60 1500
eV U9 (1999) 4 100 eV EPU5.6 (1999) 60
1400 eV SWLS (2002) 4 30 keV SW6
(2004) 6.5 19 keV
HX
VUV
SX
VUV
SX
HX
HX

• 1993 Operation 1.3 GeV
• 1996 Ramping to 1.5 GeV
• 2000 1.5 GeV Full Energy Injection (200 mA)
• 2004 Operation with Superconducting RF Cavity
• 2005 Top-up Injection at 300 mA

• Circumference 120 m
• Critical Energy 2.14 keV
• Natural Emittance 25 n mrad
• Average Pressure (200 mA) 0.68 nTorr
• Accumulated Dose gt 8000 Ah
• Life Time 10 h

New ID in planning 1 EPU-II (2006) 3 IASW6
(2006)
SX
HX
3
AL Chambers for TLS

• B-Chamber
• CNC machining in pure alcohol
• Distributed Ionization Pump
• TIG welding in clean room

• S-Chamber
• Al Extrusion
• Chemical cleaning by acid
• TIG welding in clean room

• ID-Chamber
• Surface finishing by CNC machining after TIG
  welding

4
AL Beam Duct for SW
(1) Al Beam duct (Extruded)
(2) TIG welding on one side
(3) Leakage Check
(4) Flatness Check
11 mm inner height
S.S. Taper
Al/SS Bimetal adaptor
SW6
(5) TIG Welding on the other side (with Al beam
duct installed in SW6)
Temperature of beam duct 100 K
5
Specifications for the ID Chambers
6
Gauges and Pumps

• Gauges (1E-4 1E-12 Torr)
• Extractor Type Ionization Gauges (Leybold)
• 3 Gauges in each Straight or Bending Sections
• Pumps (Oil-free)
• Roughing
• Sorption Pump (LN2) Roughing from 1 atm
• Magnetic suspended TMP Vacuum Bake out
• Molecular Drag Pump Backup pump for TMP
• UHV Pumping
• Sputtering Ionization Pump (starcell)
• NEG (lumped or strips)

7
Top-up Injection at 300 mA(routine operation
before Dec. 2005)
PLAN
Beam current I 300 mA
Life time t gt 5.5 h
Variation of Photon flux ?I / I lt 0.1
Average Pressure P lt 0.65 nTorr
8
In-Achromat Superconducting Wiggler(to be
installed at Dec. 2005)
PLAN
IASW6 (3.1 T)
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Taiwan Photon Source (TPS)
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Progress of TPS Project

• 2004.07.09
• Board of Trustee meeting decides to propose TLS2
  project.
• 2004.08.19-20 Accelerator Forum (NSRRC)
• Propose 3 GeV, 400 mA (L 300 360 m) TLS2
  concept
• 2004.10.20 Conceptual proposal for TPS
• 3 3.3 GeV, 350 mA 500 mA (L 518.4 m)
• 2004.12.07 Submit proposal to Government
• 2005.01 Accepted by National Sci. Tech. Council
  Meeting
• 2005 Conceptual Design for TPS

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Design Goals

• High stability
• Photon intensity fluctuation lt 0.1
• Beam orbit fluctuation lt 0.2µm (BW200Hz,1kHz
  sampling)
• Beam size fluctuation lt 0.1µm
• Low emittance and high brightness
• Brightness gt1021 p/s/0.1bw/mm2/mrad2 (_at_ 10 keV)
• Emittance elt 2 nm-rad
• High reliability
• High injection efficiency (gt 90)
• Machine Up-time gt 98
• Trip rate lt 1/week
• Superconducting Technologies

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Site Plan for TPS
TLS 1.5 GeV 120 m
TPS 3 GeV 518.4 m
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Parameters of TPS
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Booster Ring
- Proposed -
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Insertion Devices
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Flux and Brilliance at 3.0 GeV
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Vacuum Systems
Low impedance structure Ante-chamber Localized
pumping Low dustP lt 0.2nTorr (0mA) P lt 1nTorr
(Y1, 400mA)
Cross section of beam duct
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Features of Large B-Chambers

• 1. Photon Absorbers located far from the source
• Lower power density simple design for the
  cooling.
• Normal incident of irradiation least production
  rates for PSD and photoelectrons.
• 2. UHV pumps located at the ante-chambers
• Closed to the gas sources (Absorbers) localized
  pumping.
• Open flange without pumping holes higher
  pumping efficiency.
• 3. Lower Impedance
• Smooth cross section of beam duct least
  quantity of tapers and flange gaps.
• Pumps removed from beam duct least quantity of
  pumping holes or slots.

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Assembly Drawing for one Cell
4 Cells in 1/6 Section
(One Cell)
B1
B2
by T. L. Yang
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Chambers with Magnets

• Clearance between chambers and Q-, S-magnets is
  kept 3 mm.
• The supports for the chambers are fixed to the
  ground and isolated from the magnets and girders.

Quadrupole
Sextupole
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Deformation from Evacuation

• Length of chamber 4 m
• Thickness of halves 50 mm

B1
B2
MAX deformation 0.168 mm
MAX deformation 0.126 mm
by T. L. Yang
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Thermal Analysis - 1 for Al Crotch Absorber
1. Normal Incidence (closer to source)
2. Normal Incidence (farther from source)
Max. Pd 33 W/mm2 (at 3 GeV, 400 mA) L 2.7 m
(from BM source)
Max. Pd 22 W/mm2 (at 3 GeV, 400 mA) L 3.3 m
(from BM source)
Tmax 198 C
Tmax 266 C
Hot spot
Hot spot
To be improved
by C. K. Kuan
23
Thermal Analysis - 2 for Al Crotch Absorber
3. Saw tooth (0.4 mm / step)
4. Saw tooth (0.2 mm / step)
Max. Pd 22 W/mm2 (at 3 GeV, 400 mA) L 3.3 m
(from BM source)
Max. Pd 22 W/mm2 (at 3 GeV, 400 mA) L 3.3 m
(from BM source)
Tmax 121 C
Tmax 108 C
Hot spot
Hot spot
Better improved !
by C. K. Kuan
24
Simulation of Pressure
Modeling
MS2
B5
SS
B4
B3
MS1
B2
1.9E-6 TorrL/s
1.7E-6 TorrL/s
1.9E-6 TorrL/s
1.7E-6 TorrL/s
6.4E-7 TorrL/s
1.5E-7 TorrL/s
5.7E-7 TorrL/s
6.4E-7 TorrL/s
1.5E-7 TorrL/s

• Monte Carlo program is provided by Dr. Y.
  Suetsugu. Ref JVST A14(1), 245 (1996).
• PSD modeling. Ref A. G. Mathewson, et al, KEK
  Reports KEK-78-9 (1978).

by C. K. Chan
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Simulated Pressure Distribution
Average Pressure (B2-B5) 1.94 nTorr
MS1
SS
B3
B2
B4
MS2
B5
by C. K. Chan
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Manufacture for the B-Chambers

• 1. Bulk - A5083H321 or A6061T5 Aluminum alloys
• 2. Length 4 m, Width lt 500 mm
• 3. Machining by CNC with Alcohol Spraying
• 4. Cleaning by vapor detergent or chemical
  solvents
• 5. TIG welding (Auto-straight welding) in dust
  controlled clean room
• 6. Leakage check by RGA

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Assembly and Installations

• 1. Assembling all the vacuum chambers and pumps
  for each cell with 2 Sector Gate Valves connected
  on both ends in the clean room.
• 2. Vacuum baking (150 C, 24 h) for each cell in
  the laboratory.
• 3. Move the assembly of each cell from laboratory
  to the tunnel.
• 4. Positioning each cell vacuum system on the
  supporting frames.

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Front Ends

• ID Front Ends
• Fixed Masks, Absorber (PAB), PBPM, Heavy Metal
  Shutter (HMS)
• Pumps (IPNEG), IG(EX), Metal Gate Valve
• BM Front Ends (1)
• Pre-Mask, Absorber, PBPM, HMS
• Pumps (IPNEG), IG(EX), MGV

Build-in-one Aluminum Chamber
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Front Ends
FE Simple structure Easy alignment
ID-FE
BM-FE
ID-Chamber
Photon BPM position resolution lt 0.3µmangular
resolution lt 0.1µrad
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Structure for Fixed Maskin BM-Front End Chamber
for Pump
Pre-Mask (V) 0.2 mm (H) 2 mm for each step
Pre-Mask
for PBPM1
Synchrotron Light
7 mrad for Beam line
(2 mrad gap)
1 mrad for PBPM
by C. K. Kuan
31
Schedule (proposed)
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Conclusions

• The aluminum alloy chambers performs well.
• The B-, S-, and ID-chambers, and the low
  temperature beam ducts for SW, performs well for
  the TLS.
• It is feasible for TPS beam ducts.
• On-going works for TPS vacuum systems
• Design for the Injection Section and Diagnostic
  Sections.
• Design the primary BPM with resolution lt 0.1 µm.
• Design and test for the absorbers and high heat
  load components.
• Evaluation the new chemical cleaning procedures.
• Evaluation the impedance from monitors and
  ceramic chambers.