X
Код презентации скопируйте его
Two Devices for HINS Robyn Madrak Accelerator Physics Center (APC)
Скачать эту презентацию
Презентация на тему Two Devices for HINS Robyn Madrak Accelerator Physics Center (APC)
Скачать эту презентациюCлайд 1
*High Intensity Neutrino Source Two Devices for HINS* Robyn Madrak Accelerator Physics Center (APC) Part I: Fast Chopper Part II: Vector Modulators
Cлайд 2
HINS - Purpose * Robyn Madrak - FNAL APT Seminar - 12/16/2008 60 MeV Linac under construction at Fermilab’s meson building R&D Linac which will demonstrate novel technologies used for the first time Technical feasibility proof of (front end) for 8 GeV Linac, Project X, etc. High intensity proton source for neutrino physics/ muon storage ring experiments Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 3
Unique Aspects/Challenges Solenoidal focusing cleaner, axisymmetric beam Use of SC spoke resonators Fast ferrite phase shifters will allow multiple cavities (and RFQ) to be driven by a single 2.5 MW, 325 MHz klystron => cost savings Fast Beam Chopper * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 4
* Robyn Madrak - FNAL APT Seminar - 12/16/2008 Parameters * full un-chopped 3 msec pulse at klystron-limited 20 mA Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 5
FNAL HINS * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 6
HINS Chopper – Part I Should the HINS be extended to an 8 GeV Linac, output beam would be transferred to Fermilab’s Main Injector, with 53 MHz RF frequency HINS Linac Bunches are spaced by 325 MHz (3.1ns) In MI, RF frequency is ~53 MHz (~19ns) Don’t want bunches in the 53 MHz separatrix Chop out ~1 of every 6 bunches Additional complication: 325 ≠ n G 53 Sometimes chop 1, sometimes 2 * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 7
Traveling Wave Chopper Structure beam is deflected by traveling pulse (electric field) b(beam)=0.073 => must slow down pulse Use traveling wave “meander” structure: 50 cm long 16 mm between chopper plates 2.4 kV per plate deflection of 6mm at end of plates 6 mm .015 ″ 100Ω 20 mm ⅛″ thick substrate (e = 9.6) b=0.073 b=0.073 d = 16mm V = +2.4 kV V = -2.4 kV ~6ns b=0.073 chopper plates (meanders) deflection q = 24mRad Pwid < 6 ns * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 8
Chopper in MEBT length of chopper plates: 50 cm drift space downstream: 30 cm * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 9
Deflection length of chopper plates: 50 cm drift space downstream: 30 cm plate separation: 16 mm * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 10
Pulser Development * Robyn Madrak - FNAL APT Seminar - 12/16/2008 We need Two pulsers to drive the ~50 Ω meanders: +/- 2.4 kV Max ~5.5 ns pulse width (including rise and fall time) 53 MHz rep rate burst of 3ms @2.5Hz, or 1ms@10Hz Programmable pulse width (may sometimes chop 1 bunch, sometimes two) → Specs do not lead to an “obvious” solution Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 11
* Similar Choppers CERN-SPL LANL-SNS CERN-SPL LANL-SNS RAL/ESS FNAL HINS Beam Energy 3 MeV 2.5 MeV 2.5 MeV 2.5 MeV Electrode Length 2 X 40 cm 35 cm 34 cm 50 cm Electrode Gap 20 mm 18 mm 14 mm 16 mm Deflection Angle 5.3 mRad 18 mRad 16 mRad 24 mRad Electrode Voltage ±0.5 kV ±2.35 kV ±2.2kV ±2.4kV Pulse Rise Time < 2ns 10 ns 2 ns < 2ns Pulse Duration min 8ns 300 ns 12 ns < 5.5 ns Pulse Rep Rate 44MHz 1 MHz 2.4 MHz 53 MHz Bunch Frequency 352 MHz 402.5 MHz 280 MHz 325 MHz Burst Duration 0.6 ms 945 ns 1.5 ms 3ms, 1ms Burst Rep Rate 50 Hz 60 Hz 25 Hz 2.5, 10 Hz Chop Description 3/8 bunches On 300,off 645 ns 1 or 2/6 bunches
Cлайд 12
Combining lower voltage pulses? scope: sees ¼ of ~120V signal (25Ω/100Ω) Fet A (~60V) Fet B (~60V) 75Ω 50Ω 100Ω ferrite 50Ω t_rise =1.4 ns t_fall = 2.2ns width = 4.1ns 2.5ns/div repeat for 10ms Basic Concept: Two 60V→50Ω pulses Combined to One 120 V→100Ω pulse scope * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 13
Kentech 500V Pulser pulse control cards PSU pulse cards trigger and power dist cards output before fully assembled: one side of combiner: five 25Ω semirigid cable in parallel, with ferrite 25Ω semirigid cable * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 14
~520 V pulse 5.5 ns 1 ms of pulses @ 53 MHz 3 ms of pulses @ 53 MHz 500V Pulser Output (repeats @ 10Hz) (repeats @ 2.5Hz) June ‘06 * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 15
Pulser output 200V/div 5ns/div 3ms burst 200V/div 400ms/div 1.2 kV Pulser Nov ‘07 * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 16
Kentech Pulsers 500 V Pulser was a success Subsequent 1.2 kV pulser was a success Plan: two (1.2kV→50Ω) into one (2.4kV→100Ω) output This requires a combiner and a meander with 100Ω impedance * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 17
Microstrips in General phase velocity and impedance are determined by effective dielectric constant: Delay time (b) and Z0 may be adjusted by Adjusting d, W, and also meander pathlength Using only one trace or two in parallel Adding an air gap beneath the dielectric (changes ee); can be used to tune b * view from end view from top
Cлайд 18
FNAL Fabricated Meanders We have pursued the following: Use double meander design with air gap between meander and ground plane (50Ω w/no gap, 100Ω/w gap) Using single meander Material: Rogers TMM10i, Cu clad; e =9.8, 18’’ long (46 cm) Meander is formed by routing out traces double meander single meander single meander 20mm 40mm 78 mm * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 19
Chopper Meanders Important Aspects Material: Outgassing ? Impedance (avoid reflections) Delay time (match beam b) Pulse Behavior along length (dispersion) Coverage Factor 20mm 40mm * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 20
Meander Substrate Meander traces are generated by routing out traces on Rogers TMM10i, Cu clad Cheaper, faster than paste/firing/electrochemical deposition Test indicates acceptable vacuum properties Terry Anderson @55C 8E-08 torr 0.63 L/s (with⅓ final surface area) bakeout begins nitrogen backfill * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 21
Double Meander, Impedance Impedance measurements from 1 – 500 MHz * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 22
Double Meander, Delay * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Want b = 0.073 to match beam speed Measure pulse delay in meander: Varying distance between meander and ground plane shows sensitivity input pulse output; delayed spacing t delay (ns) b 0.062’’ 18.8 0.081 0.040’’ 21.2 0.072 0 32.3 0.047 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 23
Single Meanders: Impedance and Delay Meander 1: 95 Ω @~100 MHz Meander 2: 100.5 Ω @~325 MHz input pulse nominal 0.010″shims t delay=20.8ns t delay=20.24ns * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 24
Dispersion input pulse beginning half way end single meander 2 single meander 1 “low dispersion” input pulse beginning half way end double meander Meanders are 18″ long Look at pulse behavior along length using high f scope probe 2 ns/div 2 ns/div 2 ns/div * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 25
Coverage Factor The electric field between the chopper plates is less than that for a structure in which the entire surface is conducting This must be accounted for in the chopper design when determining the voltage needed for the desired kick conductor dielectric * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 26
Coverage Factor Measurements High frequency probe Tip is at top ground plane xy stage for position dependent measurements meander Ground; top ground plane at beam height above meander network analyzer port 1 network analyzer port 2 * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 27
input pulse @ end @end Coverage Factor Normalization Normalize to stripline with wide trace Use geometry for 50Ω – convenient For striplines Z = 120p 2/8(ln2 + pw/4h)* Use w = 25mm, 2h = 16mm * R. Collin, Foundations of Microwave Engineering Probe pickup signal (S21), 50 – 150 MHz * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 28
All Measured Coverage Factors * Robyn Madrak - FNAL APT Seminar - 12/16/2008 type Double 50Ω Double 100Ω Single 1 (low dispersion) Single 2 (high coverage) Coverage factor 71% 87% 48% 74% Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 29
Position Dependence beam RMS size 100% x * Robyn Madrak - FNAL APT Seminar - 12/16/2008 20mm = 0.79″ Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 30
3 ms pulse combined output input 50Ω cable V1→50Ω V1→50Ω 50Ω cable MN60 ferrite: three 11’’ OD, 4.5’’ ID, 1’’ thick cores 58 turns of ¼″ “superflex” cable ferrite 1 ms pulse Expect behavior to be better than this: currently we have extra unneeded cable length matching resistors (100Ω to scope 50Ω) add extra inductance Combiner 2V1→100Ω Test combiner by splitting and recombining (using our 500V pulser): Vout = 95% Vin scope *
Cлайд 31
input ferrite 46 turns of ⅜″ superflex around five 1″ MN60 cores 1700 V →100 Ω 1200 V pulse → 50 Ω 500 V pulse → 50 Ω combiner 100 Ω meander structure Kanthal 100 Ω High f probe, ⅜″ away Combiner Optimized 200 ms/div 1ms pulse 5ns/div, 1600 V * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 32
Heating in Meander Current in meander will be 2.4 kV/100 Ω = 24 A Need to test heat/current handling capacity Use 1ms/3ms pulses: (24A)2 x ⅓ x 5.3 = I2test Itest = 32 A actual pulsed current chopping DF Skin depth factor Fuses @ 180A, 3ms pulse * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Equilibrium Temperature 1ms, 10 Hz, 50A 1ms, 10Hz, 41 A 3ms, 2 Hz, 50 A T (near trace) 83 C 58 C 44C T (on trace) 65C Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 33
Chopper: Summary We have built prototypes for the necessary components for the chopper: the pulser, meander structures, and combiner The prototype pulsers from Kentech performed to specs; For a complete chopper system we need 3 more We have built a combiner suited for combining these fast pulses We have explored different layouts for the chopper plates (meander structures). The higher coverage factor single meander is the best candidate. For more details, see proceedings of Linac’08 : R. Madrak et al., “A Fast Chopper for the Fermilab High Intensity Neutrino Source (HINS)” * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 34
Aside: Application of Chopper R&D to the current accelerator Initially explored the option of using a few fast, 1 kV FETs from DEI for Chopper pulser Realized these could be used for notching in the 750 keV line: create a notch for booster kicker rise time (minimize losses) This effort was begun initially in collaboration with Doug Moehs (first attempt was chopping in the source) * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 35
Combining three DEI FETs from DEI/IXYS RF Use the same scheme as HINS pulser, combining three ~1kV → 16.7 Ω signals (x 30 = 50 Ω) ~40ns pulses 2.2ms spacing Burst of 15 pulses, repeat at 15 Hz Two pulsers: ±1.9kV 1.9 kV, ~40 ns wide pulse (on test bench w/60 dB atten) * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 36
Plates: 0.9″ spacing W1 * Notching Plates in 750 keV line (H-)
Cлайд 37
In Linac after tank 2 DV plates = 2.9 kV ~100 ns wide notch 50 ns/div 20 ns/div In Linac after tank 2 DV plates = 3.8 kV ~100 ns wide notch In booster ~40 ns wide notch In booster Notching Study ~40 ns wide notch B. Pellico, R. Tomlin B. Pellico, R. Tomlin 400 ns/div 40 ns/div *
Cлайд 38
* Robyn Madrak - FNAL APT Seminar - 12/16/2008 Part II – Vector Modulators Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 39
HINS 325 MHz RF Pulse Transformer& Oil Tank IGBT Switch & Bouncer CAP BANK 10 kV 110 kV Charging Supply 300kW MODULATOR 325 MHz 2.5 MW 1ms@10Hz or 4ms@2.5 Hz WR2300 Distribution Waveguide I Q M I Q M I Q M I Q M I Q M Fast Ferrite Vector Modulators RF Couplers I Q M I Q M I Q M I Q M I Q M I Q M 500kW I Q M I Q M I Q M I Q M I Q M I Q M 10kV 50 kW circulator M E B T R F Q S S R S S R S S R S S R H- Medium Energy Beam Transport Copper Cavities Radio Frequency Quadrupole Cryomodule #1 Cryomodule #2 TOSHIBA E3740A independent phase and amplitude control in each cavity * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 40
How it Works In a coaxial line filled with some dielectric ( , v = c/√ We vary and thus v and phase by varying H applied to the ferrite. H I ferrite outer conductor inner conductor slot in outer conductor supplied by solenoid * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 41
* Robyn Madrak - FNAL APT Seminar - 12/16/2008 Operates in full reflection mode (end is shorted) Use solenoid along with shifters: phase of reflected wave determined by of ferrite ( depends upon applied H Field) Ferrite is Al doped Yttrium Iron Garnet (YIG) – TCI Ceramics AL-400 Required rate: 1º/ s Power Rating: ~50kW (Room Temp Cavities) or ~500kW (RFQ) Fermilab’s Ferrite Phase Shifter Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 42
Modulates phase and amplitude independently: With = ( 2 - 3)/2 = ( 2 + 3)/2 90 Degree Quad Hybrid Input (split between ports 2 and 3) Output ← (Cavity) 2 3 circulator Vector Modulator: Output power ~ cos2( ) Phase shift ~ + 3 /2 Phase Shifters shorted end solenoid flux return slot * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 43
Two Phase Shifter Types For Cavities (~75 kW): 1.5 OD X 0.65 ID X 5 long garnet For RFQ (~500 kW): 3 OD X 0.65 ID X 5 long garnet * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 44
Shifter Design Details Center conductor: shrink fit during assembly Use quarter wave matching section (for 50Ω) Outer conductor has 0.020″ slot (length = 9″) to reduce eddy currents (gives faster response) solenoid (12 awg wire around G10) flux return * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 45
Other VM Parts hybrid for 1⅝ vm: Dielectric circulator for 1⅝ vm: Ferrit-Quasar circulator load: 5kw CW water cooled Altronics 6 ″hybrid for RFQ vm: MCI Filled with SF6 to prevent sparking * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 46
useful phase shift range ~120 deg. (loss < -0.2 dB) Gyromagnetic resonance (lossy) @ 2.8 MHz/Oe Phase vs. Applied Field 325 MHz Low Power meas: * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 47
Small Signal Frequency Response Open loop bandwidth: 15 kHz > 35 kHz w/feedback * Response (mixer) solenoid I Program, 10 kHz 0.1 ms 30 deg.
Cлайд 48
Slew Rate Phase Shifter Slew Rate: (above resonance) 6 deg/ms Current risetime limited by supply output, solenoid inductance Fast 300A power supply thanks to Brad Claypool, Steve Hays, Howie Pfeffer * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 49
* Robyn Madrak - FNAL APT Seminar - 12/16/2008 Beam Loading - Simulation Cavity 6 Starting and stopping the compensation 4 usec prior to beam arrival time Beam current 26 mA phiS = -45 deg Results courtesy Julien Branlard Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 50
Meson Building Test Facilities 325 MHz RF Test Cage Please do not feed the animals 2.5 MW klystron First room temperature cavity vector modulator * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 51
Meson Building Test Facilities Testing the RFQ vector modulator Testing the 1⅝″ vector modulator * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 52
Power Capabilities phase ~ ( 1 + 2)/2 here, both shifters’ solenoids driven by one power supply ( 1 = 2) * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 53
Power Capabilities 1⅝ VM for cavities: good to >75 kW Shifters alone could be used in a 200 kW VM if used with oil in ferrite part of coax line (higher power quad hybrid & circulator would be needed) RFQ VM Shifters and Hybrid filled with SF6: Good to > 500 kW Current hybrid is 6″ Stripline “500 kW” Circulator failed: Getting a new one from Ferrite * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 54
Vector Modulators: Summary The 1⅝″ vector modulators can operate well up to 75 kW (more than needed for the RT cavities) The RFQ vector modulator elements: phase shifters good to ~600 kW hybrid good to ~600 kW initial circulator failed; new Ferrite™ model on order The speed of the response for the cavity shifters is 6X as fast as the original spec bandwidth > 35 kHz for a first attempt at feedback For more details, see proceedings of Linac’08 : R. Madrak and D. Wildman, “High Power 325 MHz Vector Modulators for the Fermilab High Intensity Neutrino Source (HINS)” * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 55
* Robyn Madrak - FNAL APT Seminar - 12/16/2008 Conclusions HINS is a key part of Fermilab’s Accelerator R&D program, and likely a key part of its future physics program We have demonstrated the workability of two of its more challenging components Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 56
Backup Slides * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 57
Kentech 500V Prototype Pulser Scheme 10 pulse cards: 50V→5Ω 5 FETS/card (in parallel) each FET drives 25Ω center conductor outer conductor 5Ω 5Ω 5Ω 5Ω 5Ω 5Ω 5Ω 5Ω 5Ω 5Ω 25Ω 25Ω pulse control cards output: 500V→50Ω 25Ω semirigid cable with ferrite five 25Ω semirigid cable in parallel, with ferrite * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 58
Coverage Factor, Meanders single meander signal to 500 MHz double meander (100Ω)around 100 MHz single meander (100Ω) around 100 MHz Which gives*: * Robyn Madrak - FNAL APT Seminar - 12/16/2008 *Relative to normalization measurement; After correcting for impedance difference and reflected power type c double 87% Single 1 48% Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 59
Heating in Meander Final Pulse: 2.4 kV→Z= 100Ω, 1ms@10Hz or 3ms@2.5Hz, Chop ≤ 30% Meander Traces: 70mm thick, R(DC) = 2.7 Ω - Or - Measure power spectrum of pulses; normalize to (2.4kV)2/100 Ω x ⅓ x 0.01 = 192W Convolute with S21 thru meander; this give Pdiss = 46 W I2test x DFtest x 2.7 Ω = 46W Itest = 41 A actual pulsed power chopping DF DF 1ms @ 10Hz With safety factor, test at 50 A low power, spectrum analyzer * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 60
Notching Study +1.9 kV -1.9 kV * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 61
Using one or two single power switches: from DEI/IXYS RF min width pulses @20MHz: 20ns/div 1ms/div → cannot get to a narrow enough pulse … With two switches: Pulses are narrower, but Still not narrow enough 4ns/div * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 62
Using one or two single power switches: The DEI FETS can be used to make a very narrow pulse by charging cable in the drain But in this case we cannot attain the desired 53 MHz rep rate 20ns/div 4ns/div With a slightly lower current version of the switch: * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
Cлайд 63
Doug Moehs 20 pulses single pulses DEI FETS were useful for beam notching in H− source for the current linac ~40ns pulses 2.2ms spacing Burst of 15 pulses, repeat at 15 Hz Two pulsers: ±800V toroid response shows notched beam trigger signal (time offset) DEI FETS for H− Source * Robyn Madrak - FNAL APT Seminar - 12/16/2008 Robyn Madrak - FNAL APT Seminar - 12/16/2008
