IPAC2013 - List of Authors (Kempkes, M.K.)

Paper	Title	Page
MOPWA065	Affordable, Short Pulse MARX Modulator	828
	R.A. Phillips, M.P.J. Gaudreau, M.K. Kempkes, B.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA J.A. Casey Rockfield Research Inc., Las Vegas, Nevada, USA
	Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator for the next generation of klystrons and accelerators. For short-pulse modulators, this Marx topology provides a means to achieve astounding risetimes and flattop control that are simply not available with hard switch or transformer coupled topologies. The design is a high peak-power pulse modulator of greater efficiency than presently available, in the 100 kV to 1 MV range, for currents of 0.1 to 1 kA, pulse lengths of 0.2 to 5.0 us, and rise/fall times 10% of pulse length. A key objective of the development effort is a design which is modular and scalable, yet low cost, and easy to manufacture and maintain. The modulator will be delivered to Yale Beam Physics Laboratory for evaluation, and will be affordable for deployment at other national labs for klystron and modulator evaluation. In this paper, DTI will describe the new design and provide an update on progress.

MOPWA066	Components of Heating and Fueling of Fusion Plasmas	831
	K. Schrock, M.P.J. Gaudreau, M.K. Kempkes Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: Funded by US DOE, Grant # DE-SC0004250 Next generation fusion facilities will require many megawatts of RF power from dozens of gyrotrons. Each gyrotron requires a power system that must deliver the high-voltage power, modulate cathode voltage, and protect these expensive gyrotrons from arcing damage. It must be highly efficient, to minimize both the power and cooling costs associated with operation and to ensure high facility availability. Diversified Technologies, Inc. (DTI) has bench-tested a table-top scale ‘Buck Matrix’ modulator which uses a single set of IGBT switches for voltage regulation, arc protection, and pulse modulation. Although pulse step modulators represent a one-step solution, their size, and the complexity of their driving transformer make them more expensive than DTI’s two-step approach. DTI’s Buck Matrix modulator, with an efficiency of ~96%, cuts the size of the system in half, using a single layer of solid state switches for both voltage regulation and arc protection/modulation. This cuts the total hardware costs by a~30% or more, and eliminates the need for a separate opening switch or crowbar. DTI will present the system components of the design as well as the performance results to date.

MOPWA067	Robust High-average-power Modulator	834
	I. Roth, N. Butler, M.P.J. Gaudreau, M.K. Kempkes Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: US DOE. Grant No. DE-SC0004254 Diversified Technologies Inc. (DTI) designed a modulator which meets the requirements of the Spallation Neutron Source (SNS) modulators at Oak Ridge National Laboratory and will be less expensive than copies of the current modulators. The SNS modulators, under development for a decade, still do not meet the specifications for voltage, droop, or pulsewidth. The modulators must provide pulses of 85 kV, 165 A, with pulsewidths of 1.5 ms and voltage flatness of 1%. The current modulator switches the full power at high frequency during each pulse, and has a complex output transformer. DTI designed a modulator that meets all specifications and is less expensive. The proposed design is cheaper because there is an HV switch that operates at full current only once per pulse, a corrector that switches only 5% of the power at high frequency, a low-cost transformer-rectifier power supply, and no output transformer. DTI’s patented switch uses IGBTs, allowing the switch to operate at full capacity even if 20% of the devices fail. The modulator will be installed in 2013 at SNS to test klystrons. DTI will present the system components of the design as well as the performance results to date.

Paper

Title

Page

Affordable, Short Pulse MARX Modulator

828

R.A. Phillips, M.P.J. Gaudreau, M.K. Kempkes, B.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA
J.A. Casey
Rockfield Research Inc., Las Vegas, Nevada, USA

Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator for the next generation of klystrons and accelerators. For short-pulse modulators, this Marx topology provides a means to achieve astounding risetimes and flattop control that are simply not available with hard switch or transformer coupled topologies. The design is a high peak-power pulse modulator of greater efficiency than presently available, in the 100 kV to 1 MV range, for currents of 0.1 to 1 kA, pulse lengths of 0.2 to 5.0 us, and rise/fall times 10% of pulse length. A key objective of the development effort is a design which is modular and scalable, yet low cost, and easy to manufacture and maintain. The modulator will be delivered to Yale Beam Physics Laboratory for evaluation, and will be affordable for deployment at other national labs for klystron and modulator evaluation. In this paper, DTI will describe the new design and provide an update on progress.

MOPWA066

Components of Heating and Fueling of Fusion Plasmas

831

K. Schrock, M.P.J. Gaudreau, M.K. Kempkes
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: Funded by US DOE, Grant # DE-SC0004250
Next generation fusion facilities will require many megawatts of RF power from dozens of gyrotrons. Each gyrotron requires a power system that must deliver the high-voltage power, modulate cathode voltage, and protect these expensive gyrotrons from arcing damage. It must be highly efficient, to minimize both the power and cooling costs associated with operation and to ensure high facility availability. Diversified Technologies, Inc. (DTI) has bench-tested a table-top scale ‘Buck Matrix’ modulator which uses a single set of IGBT switches for voltage regulation, arc protection, and pulse modulation. Although pulse step modulators represent a one-step solution, their size, and the complexity of their driving transformer make them more expensive than DTI’s two-step approach. DTI’s Buck Matrix modulator, with an efficiency of ~96%, cuts the size of the system in half, using a single layer of solid state switches for both voltage regulation and arc protection/modulation. This cuts the total hardware costs by a~30% or more, and eliminates the need for a separate opening switch or crowbar. DTI will present the system components of the design as well as the performance results to date.

MOPWA067

Robust High-average-power Modulator

834

I. Roth, N. Butler, M.P.J. Gaudreau, M.K. Kempkes
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: US DOE. Grant No. DE-SC0004254
Diversified Technologies Inc. (DTI) designed a modulator which meets the requirements of the Spallation Neutron Source (SNS) modulators at Oak Ridge National Laboratory and will be less expensive than copies of the current modulators. The SNS modulators, under development for a decade, still do not meet the specifications for voltage, droop, or pulsewidth. The modulators must provide pulses of 85 kV, 165 A, with pulsewidths of 1.5 ms and voltage flatness of 1%. The current modulator switches the full power at high frequency during each pulse, and has a complex output transformer. DTI designed a modulator that meets all specifications and is less expensive. The proposed design is cheaper because there is an HV switch that operates at full current only once per pulse, a corrector that switches only 5% of the power at high frequency, a low-cost transformer-rectifier power supply, and no output transformer. DTI’s patented switch uses IGBTs, allowing the switch to operate at full capacity even if 20% of the devices fail. The modulator will be installed in 2013 at SNS to test klystrons. DTI will present the system components of the design as well as the performance results to date.