Overview of Driver Technologies for Nanosecond TEM kickers

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Overview of Driver Technologies for Nanosecond TEM kickers Anatoly Krasnykh TID/RFARED SLAC National Accelerator

Overview of Driver Technologies for Nanosecond TEM kickers Anatoly Krasnykh TID/RFARED SLAC National Accelerator Lab The 2 nd Topical Workshop on Injection and Injection Systems, PSI, April 1 -3, 2019

Outline • Introduction • Nanosecond Driver State of the Art • Switch: What we

Outline • Introduction • Nanosecond Driver State of the Art • Switch: What we are looking for? • Fast Thyratrons and Fast Solid State Devices (MOSFETs) • Known Approaches and Effects to Raise the di/dt Rates on the Resistive Loads • Driver Technology Based on the Electromagnetic Shock Wave Formation • Simplified Circuit Layouts To Produce Few Nanosecond Pulses with NLTLs • Specifics to Employ a Shock Electromagnetic Wave Approach • Effects in Advanced Semiconductor Switch Physics and Technology • Driver Technology Based on the Drift Step Recovery Processes in Semiconductor • Junction Recovery Mode in the DSRD and SOS • Simplified Circuit Layouts To Produce Few Nanosecond Pulses with the DSRD Assistance • Specifics to Employ the DSRD‐based Driver • Driver Technology Based on the Fast Ionization Processes in Semiconductors (FID) • Conclusion

Beginning of My Experience with Nanosecond Drivers 5 ns Fall time 1. 5 ns

Beginning of My Experience with Nanosecond Drivers 5 ns Fall time 1. 5 ns by Tektronix 519 or by Ferizol oscilloscopes Nanosecond Kicker Driver Technology Based on the Shock Wave Approach (Middle of 70’s) Nanosecond Drivers Technology Based on the DSRD Approaches (Middle of 80’s) Fast Magnetization (Shock Wave Formation) II Symposium on Collective Methods of Acceleration Dubna, 1976, p. 57. All Union Conference on Charged Particle Accelerators, Dubna, 1988, v. 2, p. 103.

Introduction: Nanosecond Driver State of the Art Controllable Switches for the Nanosecond Kicker Drivers:

Introduction: Nanosecond Driver State of the Art Controllable Switches for the Nanosecond Kicker Drivers: • Thyratron‐based (gas filled tubes) • Solid State Field Effect Transistor (MOSFET‐ based) What we are looking for? • • • 50 ns timing stability (less than nsec) repetition rate (range is wide, from 100 Hz to several MHz) high rates of current rise (hundreds Amperes per nanosecond) DART-II +_20 k. V kicker pulser Rise time: 10 ns 20 ns Trigger Is there any progress in gas filled tubes? • Western Vendors: E 2 V, Litton • Pulsed Technology, Ltd. (Russia) CX 1599 10 ns Jitter: 0. 2 ns di/dt: 100 A/nsec Va: 12. 5 k. V Ia: 1 k. A L 4897 A Jitter: 5 ns di/dt: 100 A/nsec Va: 20 k. V Ia: <3 k. A However, the rate of rise refers often to that part of the leading edge of the pulse between 25% and 75% of the pulse amplitude. TPI‐ 1 k/20 Jitter: <0. 5 ns di/dt: 100 A/nsec Va: 20 k. V Ia: <1 k. A The DU FEL Facility

Introduction: Nanosecond Driver State of the Art Solid State Switches (MOSFET‐based) A single MOSFET

Introduction: Nanosecond Driver State of the Art Solid State Switches (MOSFET‐based) A single MOSFET voltage hold off is less than 2 k. V, switching current is <100 A, and a rise time ~5 nsec @ high impedance load. DE and APT are leaders in the fast MOSFET industry. A nsec switching of sub k. A currents will employ an array of MOSFETs. Courtesy Ed Cook +_4 k. V @ 50 Ohm loads, ~200 ea. APT MOSFETs with a 6 nsec rise time. Fraction x-fmr with ferromagnetic cores A higher output voltage will require more cells. A rise time will degrade. For example, DARHT‐II kicker, +_18 k. V @ 50 Ohm loads, rise time is ~10 nsec 5

Introduction: Nanosecond Driver State of the Art Solid State Switches (MOSFET‐based) Behlke HTS‐ 61‐

Introduction: Nanosecond Driver State of the Art Solid State Switches (MOSFET‐based) Behlke HTS‐ 61‐ 40 (6 k. V, 400 A) Waveform of RC discharge 50 ns Switch is still ON Trigger pulse width is 20 nsec. There is no output if the trigger pulse less than 20 nsec A pulse forming network is needed to form a nanosecond pulse width 10 ns FWHMmin~12 ns The Behlke HTS 150‐ 25‐F switch based on a Si. C technology is currently discussed for the high rep rate mode of operation (15 k. V, 250 A, 4‐ 5 ns rise time) 6

Introduction: Nanosecond Driver State of the Art Advanced Fast Thyratrons Array of Powerful Solid

Introduction: Nanosecond Driver State of the Art Advanced Fast Thyratrons Array of Powerful Solid State Si‐Technology MOSFETs It is clear that above type switches cannot form nanosecond pulses without assistance of additional processes. 10 ns 7

Known Approaches and Physical Effects used to Raise the di/dt Rate There are several

Known Approaches and Physical Effects used to Raise the di/dt Rate There are several practical physical effects that can overcome the di/dt limitation for commercially available off-the-shelf (COTS) switches. For example, • Electromagnetic effect is based on the assistance of the “slow” switch by: a. nonlinear ferromagnetic media b. semiconductor media In both approaches the nonlinear characteristic of switching media (ferromagnetic and solid state plasma in semiconductors) are employed in the final stage of the driver to create multi- MW level nanosecond pulses. Both high power effects are not new: • The effects in nonlinear ferromagnetic medias were studied in the middle of the 60’s (Ivan Kataev) • The effects in semiconductors were also studied in the 60’s (Steward Krakauer) There a lot of publications where devices based these effects are presented (the drivers are mainly used in the Lab research programs)

Driver Technology Based on the Electromagnetic Shock Wave Formation (Basics) Usage of a non-linear

Driver Technology Based on the Electromagnetic Shock Wave Formation (Basics) Usage of a non-linear media to assist with the switching speed (a shock wave formation) & & Transmission Line Equations with A practical realization: • A coaxial line with ferromagnetic media • …

Driver Technology Based on the Electromagnetic Shock Wave Formation Effects of “Moving Mirror” in

Driver Technology Based on the Electromagnetic Shock Wave Formation Effects of “Moving Mirror” in the Non‐Linear Transmission Line (NLTL) Ø The EM front propagates slow in Non‐ Linear Transmission Line (NLTL) due to a magnetization process (μ>1) Ø The EM front is sharpened while it passed through NLTL. Shock wave (SW) is formed. Ø The EM propagates faster behind the front (μ≅1) Practical benefits to employ of the SW approach: • Pulse transformation from the “sine‐like” shape to the rectangular shape • Power compression (a longer time for the charging and a short time for the discharge)

Driver Technology Based on the Electromagnetic Shock Wave Formation Simplified Circuit Layouts To Produce

Driver Technology Based on the Electromagnetic Shock Wave Formation Simplified Circuit Layouts To Produce Few Nanosecond Pulses with the NLTLs II Symposium on Collective Methods of Acceleration, Dubna, 1976, p. 57. Pulse forming networks are typically pumped by the Melville stages (to form the nsec sine‐like charging pulses) The typical power compression is from 3 to 1. 5 for 250 nsec to 50 nsec pulses. JINR preprint 9‐ 87‐ 172, Dubna 1987 • Vout=140 k. V • T_pulse_plato≅ 10 nsec • T rise/fall < 5 nsec

Driver Technology Based on the Electromagnetic Shock Wave Formation There are issues of the

Driver Technology Based on the Electromagnetic Shock Wave Formation There are issues of the impedance matching of the kicker feeder with the NLTL and the output rise time. 1. 8 1. 7 CMD 5005 1. 6 mu_res Γ ~13% if H ~75 A/cm 1. 5 1. 4 1. 3 1. 2 1. 1 1 0 50 100 150 H_res, A/ cm 200 250 300 A high amplitude drive of the magnetic field in the NLTL is needed to minimize the reflections (a residual power) and get a few nanosecond rise time!

Driver Technology Based on the Electromagnetic Shock Wave Formation • Ni. Zn ferrite only

Driver Technology Based on the Electromagnetic Shock Wave Formation • Ni. Zn ferrite only practical material Fast switching time requires High magnetic field High current in the transmission line feeder this current is produced by a high voltage ‐ 10 s of k. V. • High electric fields in coax may produce the ionization in ferromagnetic media. Plasma formation and breakdown are killers of shock wave formation and the switch performance. To mitigate this phenomena a liquid dielectric is used in the NLTL. Careful design of the high voltage and broadband coax termination is required. • E_ferrite ~ 10 k. V/cm, gives the rise/fall times of ~1 nsec

Effects in Advanced Semiconductor Switch Physics and Technology The effects were studied during development

Effects in Advanced Semiconductor Switch Physics and Technology The effects were studied during development of the Step Recovery Processes in diodes. This class of diodes was designed to enhance storage and achieve an abrupt transition from reverse storage-condition to cut-off. [1. ] “P‐N Junction Charge‐Storage Diodes” was published in 1962 by J. Moll (SU), S. Krakauer (HP), and R. Shen (HU) and [2. ] “Reverse Recovery Processes in Silicon Power Rectifiers” was published in 1967 by H. Benda and E. Spenke (Siemens). Theory and effects in [1, 2] were presented and explained: • Stationary forward p-n junction behavior • Initiation of the reverse recovery effects • Effects during removal of the stored charge and development of the voltage step on the p-n junction. I. Grekhov and A. Kardo-Sysoev (Ioffe, Phys-Tech Inst. ) were pioneers for realization of the powerful Drift Step Recovery Diodes [2]

Pioneers of the Junction Step Recovery Diodes

Pioneers of the Junction Step Recovery Diodes

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor A nonlinear switching

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor A nonlinear switching media is a solid state plasma. The plasma erosion results in an abrupt current in semiconductor How Diode Switch Does Works? (basic case) • A special profile of dopant concentration is formed by the diode technology • A plasma distribution is formed after applying of short forward current pulse. • The forward current is reversed. Two plasma fronts are moving fast (vsat∝ 107 cm/sec) to each other toward to the p-n junction. • When both fronts are collided the Space Charge Region is formed. • The reverse current is abrupt in the diode and it jumps to the load. The voltage on the load is erected quickly. The stored energy in pulser starts to be delivered to the load. Courtesy [2] and I. Grekhov

Drift Step Recovery Diode (DSRD) and Silicon Opening Switch (SOS) The DSRD developed in

Drift Step Recovery Diode (DSRD) and Silicon Opening Switch (SOS) The DSRD developed in St. Petersburg (the Ioffe Institute) [SPg‐Team] The SOS developed in Ekaterinburg (the Institute of Electrophysics) [EBg‐Team] Both diodes are based on the Junction Recovery Process. There are two main modes in the fast recovery process: Ø The p‐n junction recovery interrupts the current flow (DSRD‐mode) RS Current Density ≤ 400 A/cm 2, Area of Diodes < 4 cm 2 (due to a skin effect) Multi‐MW peak output power, Rise time < 1 nsec Ø A fast growth of the resistance in the low doped part of the p‐layer interrupts the current (SOS‐mode) RS Current Density >1 k. A/cm 2, GW peak output power, Rise time > 1 nsec The EBg‐Team Classification of the Modes Horizontal scale is 5 ns/div Vertical scale is 68 k. V/div SOS‐mode S. Lyubutin et. al. Instrumental and Experimental Techniques, Vol. 43, No. 3, 2000, pp. 331 -338. A recovery is not developed in the base of the p‐n junction A=27 k. V Our VMI diodes with Vout/Vc=3. 9 and x=100 um 17

Potential-Charged & Current-Charged Transmission Lines in Drivers Potential‐Energy Storage Drivers with the ON Switch

Potential-Charged & Current-Charged Transmission Lines in Drivers Potential‐Energy Storage Drivers with the ON Switch Inductive‐Energy Storage Drivers with the OFF Switch Line‐type Blumlein‐type 10 ns Zarem‐Marshall‐Houser (ZMH)‐type There are pre‐pulse issues in the drivers based on NLTL and DSRD approaches 18

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor Simplified Circuit Layouts

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor Simplified Circuit Layouts To Produce Few Nanosecond Pulses with the DSRD Assistance 1. 25 ns A 3 MHz Run A=4. 4 k. V @50 Ohm FWHM=2. 9 ns Rise=0. 9 ns How circuit does work ‐‐ see SLAC‐PUB‐ 13477 19

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor A 3 MHz

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor A 3 MHz Run Sw 1 L 1 C 2 Sw 2 Fall=1. 2 ns FWHM=4. 4 ns Burst Mode 0. 8 k. V/div SLAC‐PUB‐ 15098 1 ns/div Sw 2: Array of Fast MOSFETs, or Magnetic Switch, or even Fast Thyratron (but careful! may be self triggered by d. V/dt)

Pulse Demonstrator #2: A k. Hz Mode of Operation for LCLS-II Pump Probe Experiments

Pulse Demonstrator #2: A k. Hz Mode of Operation for LCLS-II Pump Probe Experiments Rep Rate: 1 k. Hz 1 nsec Ampl: 6. 1 k. V A waveform demonstrates the result of a 1 k. Hz Run at a 50 Ohm resistive load A 1 k. Hz Mode was demonstrated

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor Demo Sw 1:

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor Demo Sw 1: Thyratrons (7782, HY 3189, CX 1135) (in Demo) Array of DE‐ 475, or (in System) HTS (Behlke) Kicker System 10 k. Hz Run: CMD 5005 Ni. Zn cores (130 o. C Curie Temp) Run time without cooling: 360 sec Core temperature rise: from 24 o. C to 90 o. C Core power loss: 2 W average per core An air fan is employed (d. T o. C is reduced by 1. 7 times) A 10 k. Hz Run, Sw 1: HTS 61‐ 40 A=5. 7 k. V at 50 Ohm 1 nsec

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor FWHM=10 nsec @

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor FWHM=10 nsec @ 15 k. Vp HY 3189 C 1: 16 n. F x‐fmr: w 1=2 w 2=7 6 ea. Ni. Zn OD=1. 4” C 2: 1. 7 n. F No NLTL case: A=24. 7 k. V (I=494 A) NLTL cores: OD=0. 16”, ID=0. 088” With NLTL: HFWD~124 A/cm, Hsw~55 A/cm HRE ~240 A/cm Ssw~0. 66 u. C/cm tsw= Ssw/ HRE ~2. 7 nsec

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor Potential Ways to

Driver Technology Based on the Drift Step Recovery Processes in Semiconductor Potential Ways to Tune the Pulse Shape By: 1. 2. 3. 4. 5. 6. Gradients of doping profile (fabrication process) Parameters of the pumping circuits Optimization of the current density through DSRD Employment of the bias on the DSRD stack Employment of the several DSRD stages Etc. A=5. 2 k. V @50 Ohm 1 k. V/div 625 ps/div Lifetime meas. Selection of DSRDs should be based on the measurement of the minority carrier lifetimes in the individual diodes

A 10 k. Hz TEM Kicker Structure for LCLS-II Pump Probe Experiments d te

A 10 k. Hz TEM Kicker Structure for LCLS-II Pump Probe Experiments d te c le d d e S an rme fi n Co Na Pu nose lse co nd r C Solid State primary switch (for 10 k. Hz Pulser Prototype) A 5 k. Vp output with 1. 5 nsec fronts at 50 Ohm feeder and 10 k. Hz rep. rates d e m r fi n Co L ne ed irm f on Thyratron-based or d oa Li m a r e k Kic e M r TE uctu Str Be 100 W (average) broadband 50 Ohm loads d a Lo d a Lo

Driver Technology Based on the Fast Ionization Processes in Semiconductor Basic idea for the

Driver Technology Based on the Fast Ionization Processes in Semiconductor Basic idea for the typical thyristor‐base p+npn+ structure is as follows. C A 1. 2. 3. 4. Creation of a layer of electron‐hole plasma near pn‐junction. External field moves the holes into p‐region and the electrons into n‐region. These carriers will reduce a potential barrier the near p‐n junction. The reduction of barrier turns on the injection of major carriers in the structure and the structure is in ON stage. A formation of the electron‐hole plasma layer appears if a short HV pulse (a few nsec) is applied. The pulse creates strong electric field (E > Eb) in the cathode vicinity. Impurity centers in the structure a source of the fast electrons. These electrons produce an impact ionizing process (a shock ionizing wave) in silicon. The ionizing front is moving fast (v>vsat) and the electron‐ hole plasma layer is formed. The structure is turned ON. Courtesy A. Grekhov and A. Kardo‐Sysoev 26

Driver Technology Based on the Fast Ionization Processes in Semiconductor Coreless driver circuit Driver

Driver Technology Based on the Fast Ionization Processes in Semiconductor Coreless driver circuit Driver concept FID‐type ON switches Start End DSRD‐type OFF switches The Grekhov Team (Ioffe Phys. Tech. Inst. ) Instrumental and Experimental Techniques, Vol. • 4 nsec leading and tailing edges 50, No. 3, 2007 • Smooth control: amplitude can be varied from 7 k. V to 9 k. V pulse width is controlled from 100 nsec to 600 nsec jitter is less than 0. 5 nsec 27

Kicker Drivers Based on the COTS and on the COTS + Assistance COTS means

Kicker Drivers Based on the COTS and on the COTS + Assistance COTS means Commercial Off-The-Shelf components 5 ns 10 ns 5 ns 28

Conclusion A. A fast bunch orbit control (a few nsec) is planned for use

Conclusion A. A fast bunch orbit control (a few nsec) is planned for use in several modern accelerator projects (for examples, ILC, CEPC, FCC, Modern Synchrotron Storage Ring Upgrade Projects, LCLS‐II, etc. ). Fast TEM‐mode kickers in the injection/extraction/orbit control systems are a cost effective and proven technology for rapid bunch orbit manipulations. The kicker driver technology requires use of fast controllable powerful switches. Current state of art in fast switches still needs assistance to speed up the power rise/fall times. B. Two driver concepts have been discussed: (1) an approach is based on assistance of a nonlinear transmission line (NLTL) with ferromagnetic media and (2) an approach is based on assistance of special diodes (DSRD) which are working in a specific mode of operation. In both approaches the nonlinear characteristic of switching media (ferromagnetic and solid state plasma) are employed in final stage of the pulser to form the multi MW level nanosecond pulses. In special semiconductors, the step junction recovery is an attractive technology for the statement #A due to: a. only a few k. V voltage power supply is required to produce a multi‐MW nanosecond pulses, b. since the switch assistance is normally closed, voltage stress is limited to nanosecond period, hence the susceptibility to hostile environment conditions such as ionizing radiation, mismatch, strong electromagnetic noise levels, etc. is expected to be minimal. 29

Acknowledgement I would like to thank Dr. Michael Boege for his invitation me to

Acknowledgement I would like to thank Dr. Michael Boege for his invitation me to participate and to contribute our results on this Workshop. Work supported by US Department of Energy contract DE‐AC 02‐ 76 SF 00515 Thank you for your attentions!