Specification7MWMBK.docx

Specifications for 7 Megawatt (peak), 201.25 MHz Horizontal Multi-Beam (MBK) Pulsed Klystron Amplifier for Fermilab’s Proton Linac Specification Number: MBK201FERMI

Description: Pulsed, Multi-Beam Klystron Amplifier,

201.25 MHz fixed tuned, Maximum Pulse length Video 500 µs at 15 Hz repetition rate, DC Power 7 MW (peak), 52.5 kW (average), Sealed off, electromagnetically focused, 9 3/16 inch EIA Coaxial output, Coaxial input, Ion-pumped, Water and air cooled as required.

Including: Klystron Tube, Solenoid magnets, X-ray shielding for personnel occupancy area, Tube sockets in self-contained high Voltage oil tank housing, Support frame with casters and self-locking and height adjustable feature for precision fixed floor mounting, Full documentation, Testing to specifications at factory, Final acceptance testing done at Fermilab, Shipping crate adequate for return for repairs, Periodic design and progress review meetings at the factory specified by Fermilab and vendor prior to initialization of work.

1. Electrical Specifications:

1.0 Operating Conditions: Klystron to be operated into a circulator with a VSWR of 1.2:1 or less at any phase angle over an input drive power range of 0.1 to 1 of nominal drive power requirement and over a gun Voltage range of 0.66 to 1.1 of nominal operating Gun Voltage. Typical operating conditions will be 3 dB below saturation with fast phase and amplitude feedback regulations. The klystron load will be an Alvarez linac tank with an over-coupled external Q of 48,200, loaded Q of 25,200 and resulting bandwidth of 8 KHz. Maximum linearity of the RF input drive to RF output power before saturation shall be a design goal for the tube. Fast closed feedback system loops will be provided to stabilize accurately phase and amplitude over varying proton beam loading conditions.

51 % nominal

1.30 There shall be no abrupt changes in amplitude exceeding 2 % when the RF drive is changed to produce output powers from 10 % to full power output at any time during the pulse with load VSWR less than or equal 1.2:1 at any phase angle.

1.31 Goal: The focusing magnet current tolerances shall be designed to limit the phase and amplitude variation ±3° and 1 dB

1.32 Documentation to be provided: manuals, drawings, hazard analysis, fault protection including arc detection, unpacking and installation instruction and their hazards.

2. General Specifications:

2.0 Mounting position: tube is to operate as a diode in horizontal position. Tentative Coax line output position horizontal clock-wise when looking down the tube from the collector.

2.1 Tube operating location is temperature controlled indoor laboratory space.

2.3 Collector power: the collector shall be designed to tolerate indefinitely without damage the full DC power with no RF drive.

2.4 Collector cooling water available indoor laboratory facilities: 68 °F (+ 5/– 2 °F), nominal flow 50 GPM, conductivity available 0.1-0.5 mhos/cm, input and output thermocouples; Fermilab can match other requirements if necessary.

2.5 Body cooling water available same specification as above with available flow of 10 GPM nominal.

2.6 The RF circuit of the multi-beam klystron shall be designed by the vendor to meet all the specifications contained in this document.

2.7 Multi-beam klystron gun shall be designed with all the cathode heaters operating in parallel.

2.8 The electron gun will be installed in an oil tank with high voltage feed-throughs.

2.8.1 The oil tank shall be leak proof and designed to withstand high voltage fault conditions.

2.8.2 Because of the fire safety environment, we are required to use high flash point oil such as R-Temp.

2.8.3 Electrical gradients around the cathode insulators and tube socket assembly shall be low enough so that no arcing will occur if the oil deteriorates to 20 kV/mm stand off when tested as specified in ASTM StandardD877.

2.8.4 The tank shall be designed with input and output valves to allow recycling of the oil to specifications; level sensors, viewing ports for arc detection, thermocouples, and humidity sensors for water leaks.

2.8.5 It shall be designed as part of the tube and focusing electromagnets support frame for shipment to Fermilab and returned to the factory for repair as one unit.

2.8.6 The tube’s support frame and shipping crate shall be designed so that it can be lifted out by overhead crane or forklift truck. A forklift truck will be used to move the tube into operating position. The shipping crate shall be designed so that it could be used to transport the tube back to the factory for repair.

2.10 Operating Position: The klystron, its high voltage oil gun tank, and electromagnet will be integrated as one unit and shipped as one unit. It shall be designed to operate in the horizontal position. The support frame shall include casters so that the tube assembly can be easily positioned. Jacking leg sands shall be provided for precision positioning and locking in place. The assembly frame shall provide a balanced set of lifting lugs for overhead crane lifting. The tube assembly base shall be designed for forklift truck lifting and moving into position.

2.12 RF Output Connection: The RF output shall be coupled from the output cavity of the klystron through a coaxial alumina vacuum output window assembly. A 9-3/16” coax connection shall be the interface output connection point. The output 9-3/16” coaxial line requires 2 Bar of dry nitrogen gas to prevent breakdown in the line.

2.13 If cooling of the coaxial alumina vacuum output window assembly is required, it shall be designed for water cooling.

2.14 Electromagnet will have thermocouples for monitors and interlocks, but cooling and power shall be designed and specified by the vendor.

2.15 Overall Size and Weight: Since space is limited the design effort should be directed at reducing the length of the tube. Currently we can accommodate a length of 19 to 20 feet. Tube assembly weight of 7,500 to 9,000 lbs is preferred.

2.16 Ion pump to be specified by Vendor and safe operating and interlock levels specified for safe operation of the tube.

2.17 X-Ray shielding shall be incorporated in the design of the tube that when the tube is operating at full DC or full RF power, the radiation level shall not exceed 2.5 mR/h when measured anywhere within a 18 inch radius of the tube and tube output window. (This may require a vertical 9-3/16” elbow, pointing upward, surrounded by shielding, and attached to the support frame to meet this requirement.)

2.18 The design of the focusing electromagnet in the cathode shall allow adequate cooling to protect the magnet from overheating.

2.19 The mechanical design of the tube, its packaging, shipping and handling shall have adequate safety margins for the expected encountered g-forces.

2.20 While the tube is in storage provisions shall be incorporated in the shipping crate for the attachment of an ion pump power supply.

3. Acceptance testing at the factory before shipment:

3.0 Fermilab reserves the right to witness the testing before shipping.

3.1 The testing shall demonstrate full compliance with the specification Electrical and General contained in this document.

3.2 With the tube on the vendors test stand and the filament set to specified current and voltage; measure and plot peak beam current versus cathode voltage in 5 kV intervals continuously up to the maximum specified cathode voltage. The log-log plot shall be a straight line and the perveance determined from the line shall be the specified perveance.

3.3 With the tube on the vendors test stand and the cathode voltage and filament current set for maximum RF power output and operating into a test resistive calorimeter load (VSWR less than or equal 1.2:1) demonstrate or measure compliance with specifications:

a) 1.5 peak RF power

b) 1.9 average RF Power

c) 1.10 Tube Efficiency

d) 1.11 Tube Gain

e) 1.12 Bandwidth

f) 1.13 Gain linearity

g) 1.15 Harmonics

h) 1.16 Spurious Output

i) 1.17 Input Match

j) 1.18 RF Power Output no RF drive

k) 1.28 Abrupt Change with RF drive change at six equally spaced VSWR over 360°.

3.4 At one VSWR phase angle and six equally spaced 5 kV intervals up to the maximum specified cathode voltage, plot the input to output transfer curve from zero to full power output. It should be continuous and meet the linearity specification.

3.5 Present test data concerning compliance with Specifications: 1.14, 1.19, 1.20, 1.21, 1.22, 1.24, 1.25, 1.26 1nd 1.29.

3.6 The vendor shall provide standard quality conformance test procedures which documents optimum parameters and performance limits as part of the vendor’s performance inspection tests. The inspections should include but not be limited to: cooling circuits, window pressure tests, heater tests, vacuum tests (including 24 hours ion pump off test), solenoid settings, etc., as well as RF power tests

3.7 Measure and demonstrate at full RF power output into matched load with VSWR less than 1.20:1; a low window sparking rate ( a few per day to start with), klystron vacuum stays within specifications and limits, and body current say within limits.

4. Final Acceptance Testing at Fermilab:

4.0 With the tube on the Fermilab test stand and the filament set to specified current and voltage; measure and plot peak beam current versus cathode voltage in 5 kV intervals continuously up to the maximum specified cathode voltage. The log-log plot shall be a straight line and the perveance determined from the line shall be the specified perveance.

4.1 With the tube on the Fermilab test stand and the cathode voltage and filament current set for maximum RF power output and operating into a test resistive calorimeter load (VSWR less than or equal 1.2:1) demonstrate or measure compliance with specifications:

a) 1.5 peak RF power

b) 1.9 average RF Power

c) 1.10 Tube Efficiency

d) 1.11 Tube Gain

e) 1.12 Bandwidth

f) 1.13 Gain linearity

g) 1.15 Harmonics

h) 1.16 Spurious Output

i) 1.17 Input Match

j) 1.18 RF Power Output no RF drive

k) 1.28 Abrupt Change with RF drive change at one VSWR.

4.2 At one VSWR phase angle and six equally spaced 5 kV intervals upto the maximum specified cathode voltage, plot the input to output transfer curve from zero to full power output.

4.3 On Fermilab’s test stand measure and demonstrate at full RF power output into matched load with VSWR less than 1.20:1; a low window sparking rate ( a few per day to start with), klystron vacuum stays within specifications and limits, and body current say within limits.

5. Miscellaneous Items:

5.0 Full documentation, manuals, drawings, handling, operating procedures, hazards, tube protections from faults.

5.1 A plan for periodic design and progress review meeting at the factory.

5.2 Together with Fermilab, generate a listing of the necessary connectors for water cooling, connectors and valves on the oil tank, connectors for high voltage connections, grounding, arc detector ports, thermocouples.

5.3 In the proposal include an option to purchase six additional tubes after successful acceptance testing at Fermilab.

5.3.1 The additional purchases should include cost and delivery schedule.