JPARC RFQ Design

1
J-PARC RFQ Design

• Tom Page
• Proton Driver Meeting
• 05/05/05

2
Information we have

• 19 drawings
• Vacuum chamber assembly drawings.
• Cavity assembly drawings.
• Vane end details (pdf).
• Various papers describing physics design.

3
J-PARC Front End system
4
RFQ pictures
Installed RFQ
5
RFQ Assembly
6
RFQ Assembly isometric view
Complete assembly weight approximately 13,000
15,000 lbs. This does not include the table which
supports the RFQ.
7
RFQ Assembly exploded view
Upper vacuum chamber
Cavity assembly
Lower vacuum chamber
(Cavity end plates not shown.)
8
RFQ Assembly End view / cross section
Cross section
End view
9
Vacuum chamber lower section
10
Cavity assembly details
(4) Quadrants each 3115 mm long, made from 0.2
doped oxygen free copper (OFC) pillars
Side view showing bolted connection.
Assembled
Exploded view
11
Cavity assembly details keys(?)
12
Vane ends
Side view showing bolted connection
13
Vane ends (cont.)
Vane exit detail
Vane entrance detail
14
p(PI)-mode Stabilizing Loop (PISL)
15
PISL sealing detail
16
Water cooling system
Plugs visible
Cooling tube detail
Cooling holes
17
Water cooling system (cont.)
Cooling tubes enter through bottom of vacuum
chamber.
18
Cavity end plate (injection shown)
19
Monitors, tuners and couplers(30 mA-RFQ)

• 16 RF-field pick-up monitors
• 14 fixed stab-tuners with vacuum ports
• 6 movable stab-tuners
• 2 RF-couplers

20
Movable tuner detail
(6) Movable stab-tuners are used to tune the
resonant frequency during operation.
21
Coupler
(2) RF couplers at different longitudinal
positions.
22
More detail needed

• Quadrant fabrication drawings
• Fabrication tolerances of vanes
• Assembly keying and tolerances
• PISL details
• Coupler and tuner details

23
Decisions

• Decision needed for RFQ technology choice
• Bolted assembly with separate vacuum chamber
  (30mA J-PARC).
• Laser welded assembly with integrated vacuum
  (50mA J-PARC).
• Brazed assembly with integrated vacuum (SNS style
  built by LBNL).
• Determine number of segments and length of
  segments.

24
Design / Analysis required

• Mechanical design
• Support structure for cavity
• Vacuum chamber (if necessary)
• Cavity assembly details and processes (laser
  welding, brazing, etc.)
• Thermal analysis / design of cavity
• Cooling water requirements.
• Thermal stresses.
• Frequency shift WRT temperature.
• Coupler and tuner design.

25
Possible prototypes

• Small length assembly prototype
• Demonstrate assembly technique.
• Determine manufacturing steps.
• Determine achievable assembly tolerances.
• Vane prototype to investigate vane machining
• Vane profile tooling.
• Determine machining tolerances.
• Find capable vendors.

26
Next steps

• Start looking at the SNS brazed RFQ design.
• Looks like we may have a complete design package
  for this RFQ (lots of drawings).
• Try to get more information on the J-PARC 50 mA
  laser welded design.
• Work of small scale prototypes of chosen design.