Two Devices for HINS Robyn Madrak Accelerator Physics Center (APC)

Содержание

1. Two Devices for HINS Robyn Madrak Accelerator Physics Center (APC)
2. HINS - PurposeRobyn Madrak - FNAL APT
3. Unique Aspects/Challenges Solenoidal focusing  cleaner, axisymmetric
4. Robyn Madrak - FNAL APT Seminar -
5. FNAL HINSRobyn Madrak - FNAL APT Seminar - 12/16/2008
6. HINS Chopper – Part I Should the
7. Traveling Wave Chopper Structure beam is deflected
8. Chopper in MEBTlength of chopper plates: 50
9. Deflectionlength of chopper plates: 50 cmdrift space
10. Pulser DevelopmentRobyn Madrak - FNAL APT Seminar
11. Similar ChoppersCERN-SPLLANL-SNS
12. Combining lower voltage pulses?scope:sees ¼ of ~120V
13. Kentech 500V Pulserpulsecontrol cardsPSUpulsecardstrigger and power
14. ~520 V pulse
15. Pulser output200V/div 5ns/div3ms burst200V/div 400ms/div1.2 kV PulserNov ‘07Robyn Madrak - FNAL APT Seminar - 12/16/2008
16. Kentech Pulsers500 V Pulser was a successSubsequent
17. Microstrips in Generalphase velocity and impedance aredetermined
18. FNAL Fabricated MeandersWe have pursued the following:Use
19. Chopper MeandersImportant AspectsMaterial: Outgassing ?Impedance (avoid reflections)Delay time
20. Meander Substrate Meander traces are generated by
21. Double Meander, ImpedanceImpedance measurements from 1 – 500 MHzRobyn Madrak - FNAL APT Seminar - 12/16/2008
22. Double Meander, DelayRobyn Madrak - FNAL APT
23. Single Meanders: Impedance and DelayMeander 1: 95
24. Dispersioninput pulse beginninghalf way
25. Coverage Factor The electric field between the
26. Coverage Factor MeasurementsHigh frequency probeTip is at
27. input pulse@ end@endCoverage Factor NormalizationNormalize to stripline
28. All Measured Coverage FactorsRobyn Madrak - FNAL APT Seminar - 12/16/2008
29. Position Dependencebeam RMS size100%xRobyn Madrak - FNAL APT Seminar - 12/16/200820mm = 0.79″
30. 3 ms pulsecombined outputinput50Ω cableV1→50ΩV1→50Ω50Ω cable MN60
31. inputferrite46 turns of ⅜″ superflex around five
32. Heating in MeanderCurrent in meander will be
33. Chopper: SummaryWe have built prototypes for the
34. Aside: Application of Chopper R&Dto the current
35. Combining three DEI FETsfrom DEI/IXYS RFUse the
36. Plates: 0.9″spacingW1Notching Plates in 750 keV line (H-)
37. In Linac after tank 2DV plates =
38. Robyn Madrak - FNAL APT Seminar - 12/16/2008Part II – Vector Modulators
39. HINS 325 MHz RFPulse Transformer& Oil TankIGBT
40. How it WorksIn a coaxial line filled
41. Robyn Madrak - FNAL APT Seminar -
42. Modulates phase and amplitude independently: With  =
43. Two Phase Shifter TypesFor Cavities (~75 kW):1.5
44. Shifter Design Details Center conductor: shrink fit
45. Other VM Partshybrid for 1⅝ vm: Dielectriccirculator
46. useful phase shift range ~120 deg. (loss
47. Small Signal Frequency ResponseOpen loop bandwidth: 15
48. Slew RatePhase Shifter Slew Rate:(above resonance)6 deg/msCurrent
49. Robyn Madrak - FNAL APT Seminar -
50. Meson Building Test Facilities325 MHzRF Test CagePlease
51. Meson Building Test FacilitiesTesting the RFQ vector
52. Power Capabilitiesphase ~ (1 + 2)/2here, both
53. Power Capabilities 1⅝ VM for cavities: good
54. Vector Modulators: Summary The 1⅝″ vector modulators
55. Robyn Madrak - FNAL APT Seminar -
56. Backup SlidesRobyn Madrak - FNAL APT Seminar - 12/16/2008
57. Kentech 500V Prototype Pulser Scheme10 pulse cards:
58. Coverage Factor, Meanderssingle meander signal to 500
59. Heating in MeanderFinal Pulse: 2.4 kV→Z= 100Ω,
60. Notching Study+1.9 kV-1.9 kVRobyn Madrak - FNAL APT Seminar - 12/16/2008
61. Using one or two single power switches:from
62. Using one or two single power switches:
63. Doug Moehs20 pulsessingle pulses DEI FETS were
64. Скачать презентанцию

HINS - PurposeRobyn 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

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Two Devices for HINS Robyn Madrak Accelerator Physics Center (APC)

Слайды и текст этой презентации

Слайд 1High Intensity Neutrino Source
Two Devices for HINS
Robyn Madrak
Accelerator Physics

Center (APC)
Part I: Fast
Chopper
Part II: Vector
Modulators

Слайд 2HINS - 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

HINS - PurposeRobyn Madrak - FNAL APT Seminar - 12/16/2008 60 MeV Linac under construction at Fermilab’s

Слайд 3Unique 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

Unique Aspects/Challenges Solenoidal focusing  cleaner, axisymmetric beam Use of SC spoke resonators Fast ferrite phase shifters

Слайд 4Robyn Madrak - FNAL APT Seminar - 12/16/2008
Parameters
* full un-chopped

3 msec pulse at klystron-limited 20 mA

Слайд 5FNAL HINS
Robyn Madrak - FNAL APT Seminar - 12/16/2008

Слайд 6HINS 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

HINS Chopper – Part I Should the HINS be extended to an 8 GeV Linac, output beam

Слайд 7Traveling 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

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

Traveling Wave Chopper Structure beam is deflected by traveling pulse (electric field) b(beam)=0.073 => must slow down

Слайд 8Chopper in MEBT
length of chopper plates: 50 cm
drift space downstream:

30 cm
Robyn Madrak - FNAL APT Seminar - 12/16/2008

Chopper in MEBTlength of chopper plates: 50 cmdrift space downstream: 30 cmRobyn Madrak - FNAL APT

Слайд 9Deflection
length of chopper plates: 50 cm
drift space downstream: 30

cm
plate separation: 16

Robyn Madrak - FNAL APT Seminar - 12/16/2008

Deflectionlength of chopper plates: 50 cmdrift space downstream: 30 cmplate separation:

Слайд 10Pulser 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

Pulser DevelopmentRobyn Madrak - FNAL APT Seminar - 12/16/2008We needTwo pulsers to drive the ~50 Ω meanders:

Слайд 11Similar Choppers
CERN-SPL
LANL-SNS

Слайд 12Combining 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

Слайд 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

Kentech 500V Pulserpulsecontrol cardsPSUpulsecardstrigger and power dist cardsoutputbefore fully assembled:one side of combiner:five 25Ω semirigid cablein

Слайд 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

~520 V pulse 5.5 ns1 ms of pulses@ 53 MHz3 ms of pulses@

Слайд 15Pulser 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

Слайд 16Kentech 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

Kentech Pulsers500 V Pulser was a successSubsequent 1.2 kV pulser was a successPlan: two (1.2kV→50Ω) into one

Слайд 17Microstrips 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

Microstrips in Generalphase velocity and impedance aredetermined by effective dielectric constant:Delay time (b) and Z0 may be

Слайд 18FNAL 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

20mm

40mm

78 mm

Robyn Madrak - FNAL APT Seminar - 12/16/2008

FNAL Fabricated MeandersWe have pursued the following:Use double meander design with air gap between meander and ground

Слайд 19Chopper 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

Chopper MeandersImportant AspectsMaterial: Outgassing ?Impedance (avoid reflections)Delay time (match beam b)Pulse Behavior along length (dispersion)Coverage Factor20mm40mmRobyn Madrak -

Слайд 20Meander 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

Meander Substrate Meander traces are generated by routing out traces on Rogers TMM10i, Cu clad Cheaper, faster

Слайд 21Double Meander, Impedance
Impedance measurements from 1 – 500 MHz
Robyn Madrak

- FNAL APT Seminar - 12/16/2008

Слайд 22Double 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

Double Meander, DelayRobyn Madrak - FNAL APT Seminar - 12/16/2008 Want b = 0.073 to match beam

Слайд 23Single 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

Single Meanders: Impedance and DelayMeander 1: 95 Ω @~100 MHzMeander 2: 100.5 Ω @~325 MHzinput pulsenominal0.010″shims t

Слайд 24Dispersion

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

Robyn Madrak - FNAL APT Seminar - 12/16/2008

Dispersioninput pulse beginninghalf way endsingle meander 2 single meander 1“low dispersion”input pulse beginninghalf

Слайд 25Coverage 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

Coverage Factor The electric field between the chopper plates is less than that for a structure in

Слайд 26Coverage 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

Coverage Factor MeasurementsHigh frequency probeTip is at top ground planexy stage for position dependent measurementsmeanderGround;top ground planeat

Слайд 27input 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

input pulse@ end@endCoverage Factor NormalizationNormalize to stripline with wide trace Use geometry for 50Ω – convenient For

Слайд 28All Measured Coverage Factors
Robyn Madrak - FNAL APT Seminar -

12/16/2008

Слайд 29Position Dependence
beam RMS size
100%
x
Robyn Madrak - FNAL APT Seminar -

12/16/2008
20mm = 0.79″

Слайд 303 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

3 ms pulsecombined outputinput50Ω cableV1→50ΩV1→50Ω50Ω cable MN60 ferrite: three 11’’ OD, 4.5’’ ID, 1’’ thick cores 58

Слайд 31input
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

inputferrite46 turns of ⅜″ superflex around five 1″ MN60 cores1700 V →100 Ω1200 V pulse → 50

Слайд 32Heating 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

Heating in MeanderCurrent in meander will be 2.4 kV/100 Ω = 24 ANeed to test heat/current handling

Слайд 33Chopper: 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

Chopper: SummaryWe have built prototypes for the necessary components for the chopper: the pulser, meander structures, and

Слайд 34Aside: 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

Aside: Application of Chopper R&Dto the current accelerator Initially explored the option of using a few fast,

Слайд 35Combining 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

Combining three DEI FETsfrom DEI/IXYS RFUse the same scheme as HINS pulser, combining three ~1kV → 16.7

Слайд 36Plates: 0.9″
spacing
W1
Notching Plates in 750 keV line (H-)

Слайд 37In 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

400 ns/div

40 ns/div

In Linac after tank 2DV plates = 2.9 kV~100 ns wide notch50 ns/div20 ns/divIn Linac after tank

Слайд 38Robyn Madrak - FNAL APT Seminar - 12/16/2008
Part II –

Vector Modulators

Слайд 39HINS 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

circulator

R F Q

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

HINS 325 MHz RFPulse Transformer& Oil TankIGBT Switch & BouncerCAPBANK10 kV110 kVChargingSupply300kWMODULATOR325 MHz2.5 MW1ms@10Hzor4ms@2.5 HzWR2300 Distribution WaveguideIQMIQMIQMIQMIQMFast

Слайд 40How 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.

ferrite

outer
conductor

inner
conductor

slot
in outer
conductor

supplied by
solenoid

Robyn Madrak - FNAL APT Seminar - 12/16/2008

How it WorksIn a coaxial line filled with some dielectric (,v = c/√We vary  and thus

Слайд 41Robyn 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 - 12/16/2008Operates in full reflection mode (end is shorted)Use solenoid along

Слайд 42Modulates 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

Modulates phase and amplitude independently: With  = (2 - 3)/2 

Слайд 43Two 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

Слайд 44Shifter 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

Shifter Design Details Center conductor: shrink fit during assembly Use quarter wave matching section(for 50Ω) Outer conductor

Слайд 45Other 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

Other VM Partshybrid for 1⅝ vm: Dielectriccirculator for 1⅝ vm: Ferrit-Quasarcirculator load:5kw CW water cooledAltronics6 ″hybrid for

Слайд 46useful 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

useful phase shift range ~120 deg. (loss < -0.2 dB)Gyromagnetic resonance(lossy)@ 2.8 MHz/OePhase vs. Applied Field325 MHz

Слайд 47Small Signal Frequency Response
Open loop bandwidth: 15 kHz
> 35 kHz

w/feedback
Response
(mixer)

solenoid I
Program, 10 kHz
0.1 ms
30 deg.

Small Signal Frequency ResponseOpen loop bandwidth: 15 kHz> 35 kHz w/feedbackResponse(mixer) solenoid I Program, 10 kHz0.1 ms30

Слайд 48Slew 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

Slew RatePhase Shifter Slew Rate:(above resonance)6 deg/msCurrent risetime limited by supply output, solenoid inductanceFast 300A power supply

Слайд 49Robyn 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 - 12/16/2008Beam Loading - SimulationCavity 6Starting and stopping the compensation 4

Слайд 50Meson 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

Meson Building Test Facilities325 MHzRF Test CagePlease do not feed the animals2.5 MW klystronFirst room temperature cavityvectormodulatorRobyn

Слайд 51Meson Building Test Facilities
Testing the RFQ vector modulator
Testing the 1⅝″

vector modulator
Robyn Madrak - FNAL APT Seminar - 12/16/2008

Meson Building Test FacilitiesTesting the RFQ vector modulatorTesting the 1⅝″ vector modulatorRobyn Madrak - FNAL APT Seminar

Слайд 52Power Capabilities
phase ~ (1 + 2)/2
here, both shifters’ solenoids driven

by one power supply
(1 = 2)
Robyn Madrak - FNAL APT

Seminar - 12/16/2008

Power Capabilitiesphase ~ (1 + 2)/2here, both shifters’ solenoids driven by one power supply(1 = 2)Robyn Madrak

Слайд 53Power 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

Power Capabilities 1⅝ VM for cavities: good to >75 kW Shifters alone could be used in a

Слайд 54Vector 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

Vector Modulators: Summary The 1⅝″ vector modulators can operate well up to 75 kW (more than needed

Слайд 55Robyn 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 - 12/16/2008Conclusions HINS is a key part of Fermilab’s Accelerator R&D

Слайд 56Backup Slides
Robyn Madrak - FNAL APT Seminar - 12/16/2008

Слайд 57Kentech 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

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

Kentech 500V Prototype Pulser Scheme10 pulse cards: 50V→5Ω5 FETS/card (in parallel)each FET drives 25Ωcenter conductorouter conductor5Ω 5Ω

Слайд 58Coverage 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

Coverage Factor, Meanderssingle meander signal to 500 MHzdouble meander (100Ω)around 100 MHzsingle meander (100Ω) around 100 MHzWhich

Слайд 59Heating 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

1ms @ 10Hz

 With safety factor, test at 50 A

low power, spectrum analyzer

Robyn Madrak - FNAL APT Seminar - 12/16/2008

Heating in MeanderFinal Pulse: 2.4 kV→Z= 100Ω, 1ms@10Hz or 3ms@2.5Hz, Chop ≤ 30%Meander Traces: 70mm thick, R(DC)

Слайд 60Notching Study
+1.9 kV
-1.9 kV
Robyn Madrak - FNAL APT Seminar -

12/16/2008

Слайд 61Using 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

Using one or two single power switches:from DEI/IXYS RFmin width pulses @20MHz:20ns/div1ms/div→ cannot get to a narrow

Слайд 62Using 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

Using one or two single power switches: The DEI FETS can be used to make a very

Слайд 63Doug 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

Doug Moehs20 pulsessingle pulses DEI FETS were useful for beam notching in H− source for the current

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Two Devices for HINS Robyn Madrak Accelerator Physics Center (APC)

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Слайды и текст этой презентации

Слайд 1*High Intensity Neutrino SourceTwo Devices for HINS*Robyn Madrak Accelerator Physics

Center (APC)Part I: FastChopperPart II: Vector Modulators

Слайд 2HINS - PurposeRobyn Madrak - FNAL APT Seminar - 12/16/2008

60 MeV Linac under construction at Fermilab’s meson building R&D

Слайд 3Unique Aspects/Challenges Solenoidal focusing  cleaner, axisymmetric beam Use of

SC spoke resonators Fast ferrite phase shifters will allow

Слайд 4Robyn Madrak - FNAL APT Seminar - 12/16/2008Parameters* full un-chopped

3 msec pulse at klystron-limited 20 mA

Слайд 5FNAL HINSRobyn Madrak - FNAL APT Seminar - 12/16/2008

Слайд 6HINS Chopper – Part I Should the HINS be extended

to an 8 GeV Linac, output beam would be transferred

Слайд 7Traveling Wave Chopper Structure beam is deflected by traveling pulse

(electric field) b(beam)=0.073 => must slow down pulseUse traveling wave

Слайд 8Chopper in MEBTlength of chopper plates: 50 cmdrift space downstream:

30 cmRobyn Madrak - FNAL APT Seminar - 12/16/2008

Слайд 9Deflectionlength of chopper plates: 50 cmdrift space downstream: 30

cmplate separation: 16

Слайд 10Pulser DevelopmentRobyn Madrak - FNAL APT Seminar - 12/16/2008We needTwo

pulsers to drive the ~50 Ω meanders: +/- 2.4 kVMax

Слайд 11Similar ChoppersCERN-SPLLANL-SNS

Слайд 12Combining lower voltage pulses?scope:sees ¼ of ~120V signal(25Ω/100Ω)Fet A(~60V)Fet B(~60V)75Ω50Ω100Ωferrite50Ωt_rise

=1.4 nst_fall = 2.2nswidth = 4.1ns2.5ns/divrepeat for 10ms Basic Concept:Two

Слайд 13 Kentech 500V Pulserpulsecontrol cardsPSUpulsecardstrigger and power dist cardsoutputbefore fully

assembled:one side of combiner:five 25Ω semirigid cablein parallel, with ferrite

Слайд 14~520 V pulse 5.5 ns1 ms

of pulses@ 53 MHz3 ms of pulses@ 53 MHz500V Pulser

Слайд 15Pulser output200V/div 5ns/div3ms burst200V/div 400ms/div1.2 kV PulserNov ‘07Robyn Madrak -

FNAL APT Seminar - 12/16/2008

Слайд 16Kentech Pulsers500 V Pulser was a successSubsequent 1.2 kV pulser

was a successPlan: two (1.2kV→50Ω) into one (2.4kV→100Ω) outputThis requires

Слайд 17Microstrips in Generalphase velocity and impedance aredetermined by effective dielectric

constant:Delay time (b) and Z0 may be adjusted by Adjusting

Слайд 18FNAL Fabricated MeandersWe have pursued the following:Use double meander design

with air gap between meander and ground plane

Слайд 19Chopper MeandersImportant AspectsMaterial: Outgassing ?Impedance (avoid reflections)Delay time (match beam b)Pulse

Behavior along length (dispersion)Coverage Factor20mm40mmRobyn Madrak - FNAL APT Seminar

Слайд 20Meander Substrate Meander traces are generated by routing out traces

on Rogers TMM10i, Cu clad Cheaper, faster than paste/firing/electrochemical deposition

Слайд 21Double Meander, ImpedanceImpedance measurements from 1 – 500 MHzRobyn Madrak

- FNAL APT Seminar - 12/16/2008

Слайд 22Double Meander, DelayRobyn Madrak - FNAL APT Seminar - 12/16/2008

Want b = 0.073 to match beam speed Measure pulse

Слайд 23Single Meanders: Impedance and DelayMeander 1: 95 Ω @~100 MHzMeander

2: 100.5 Ω @~325 MHzinput pulsenominal0.010″shims t delay=20.8nst delay=20.24nsRobyn Madrak

Слайд 24Dispersioninput pulse beginninghalf way endsingle meander 2

single meander 1“low dispersion”input pulse beginninghalf way

Слайд 25Coverage Factor The electric field between the chopper plates is

less than that for a structure in which the entire

Слайд 26Coverage Factor MeasurementsHigh frequency probeTip is at top ground planexy

stage for position dependent measurementsmeanderGround;top ground planeat beam height abovemeandernetwork

Слайд 27input pulse@ end@endCoverage Factor NormalizationNormalize to stripline with wide trace

Use geometry for 50Ω – convenient For striplines

Слайд 28All Measured Coverage FactorsRobyn Madrak - FNAL APT Seminar -

12/16/2008

Слайд 29Position Dependencebeam RMS size100%xRobyn Madrak - FNAL APT Seminar -

12/16/200820mm = 0.79″

Слайд 303 ms pulsecombined outputinput50Ω cableV1→50ΩV1→50Ω50Ω cable MN60 ferrite: three 11’’

OD, 4.5’’ ID, 1’’ thick cores 58 turns of ¼″

Слайд 31inputferrite46 turns of ⅜″ superflex around five 1″ MN60 cores1700

V →100 Ω1200 V pulse → 50 Ω500 V pulse

Слайд 32Heating in MeanderCurrent in meander will be 2.4 kV/100 Ω

= 24 ANeed to test heat/current handling capacityUse 1ms/3ms pulses:

Слайд 33Chopper: SummaryWe have built prototypes for the necessary components for

the chopper: the pulser, meander structures, and combiner The prototype

Слайд 34Aside: Application of Chopper R&Dto the current accelerator Initially explored

the option of using a few fast, 1 kV FETs

Слайд 35Combining three DEI FETsfrom DEI/IXYS RFUse the same scheme as

HINS pulser, combining three ~1kV → 16.7 Ω signals (x

Слайд 36Plates: 0.9″spacingW1Notching Plates in 750 keV line (H-)

Слайд 37In Linac after tank 2DV plates = 2.9 kV~100 ns

wide notch50 ns/div20 ns/divIn Linac after tank 2DV plates =

Слайд 38Robyn Madrak - FNAL APT Seminar - 12/16/2008Part II –

Vector Modulators

Слайд 39HINS 325 MHz RFPulse Transformer& Oil TankIGBT Switch & BouncerCAPBANK10

kV110 kVChargingSupply300kWMODULATOR325 MHz2.5 MW1ms@10Hzor4ms@2.5 HzWR2300 Distribution WaveguideIQMIQMIQMIQMIQMFast Ferrite VectorModulatorsRF CouplersIQMIQMIQMIQMIQMIQM500kWIQMIQMIQMIQMIQMIQM10kV50

Слайд 40How it WorksIn a coaxial line filled with some dielectric

Слайд 1High Intensity Neutrino Source
Two Devices for HINS
Robyn Madrak
Accelerator Physics

Center (APC)
Part I: Fast
Chopper
Part II: Vector
Modulators

Слайд 2HINS - Purpose
Robyn Madrak - FNAL APT Seminar - 12/16/2008

60 MeV Linac under construction at Fermilab’s meson building

R&D

Слайд 3Unique Aspects/Challenges
Solenoidal focusing  cleaner, axisymmetric beam

Use of

SC spoke resonators

Fast ferrite phase shifters
will allow

Слайд 4Robyn Madrak - FNAL APT Seminar - 12/16/2008
Parameters
* full un-chopped

Слайд 5FNAL HINS
Robyn Madrak - FNAL APT Seminar - 12/16/2008

Слайд 6HINS Chopper – Part I
Should the HINS be extended

Слайд 7Traveling Wave Chopper Structure
beam is deflected by traveling pulse

(electric field)

b(beam)=0.073 => must slow down pulse
Use traveling wave

Слайд 8Chopper in MEBT
length of chopper plates: 50 cm
drift space downstream:

30 cm
Robyn Madrak - FNAL APT Seminar - 12/16/2008

Слайд 9Deflection
length of chopper plates: 50 cm
drift space downstream: 30

cm
plate separation: 16

Слайд 10Pulser Development
Robyn Madrak - FNAL APT Seminar - 12/16/2008
We need

Two

pulsers to drive the ~50 Ω meanders: +/- 2.4 kV
Max

Слайд 11Similar Choppers
CERN-SPL
LANL-SNS

Слайд 12Combining 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

Слайд 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

Слайд 14~520 V pulse
5.5 ns

1 ms

of pulses
@ 53 MHz
3 ms of pulses
@ 53 MHz
500V Pulser

Слайд 15Pulser output
200V/div
5ns/div

3ms burst
200V/div
400ms/div

1.2 kV Pulser
Nov ‘07
Robyn Madrak -

Слайд 16Kentech 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

Слайд 17Microstrips in General
phase velocity and impedance are
determined by effective dielectric

constant:
Delay time (b) and Z0 may be adjusted by

Adjusting

Слайд 18FNAL Fabricated Meanders
We have pursued the following:

Use double meander design

Слайд 19Chopper 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

Слайд 20Meander Substrate
Meander traces are generated by routing out traces

on Rogers TMM10i, Cu clad

Cheaper, faster than paste/firing/electrochemical deposition

Слайд 21Double Meander, Impedance
Impedance measurements from 1 – 500 MHz
Robyn Madrak

Слайд 22Double Meander, Delay
Robyn Madrak - FNAL APT Seminar - 12/16/2008

Want b = 0.073 to match beam speed

Measure pulse

Слайд 23Single 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

Слайд 24Dispersion

input pulse
beginning
half way
end

single meander 2

single meander 1
“low dispersion”

input pulse
beginning
half way

Слайд 25Coverage Factor
The electric field between the chopper plates is

Слайд 26Coverage 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

Слайд 27input pulse
@ end
@end
Coverage Factor Normalization
Normalize to stripline with wide trace

Use geometry for 50Ω – convenient

For striplines

Слайд 28All Measured Coverage Factors
Robyn Madrak - FNAL APT Seminar -

Слайд 29Position Dependence
beam RMS size
100%
x
Robyn Madrak - FNAL APT Seminar -

12/16/2008
20mm = 0.79″

Слайд 303 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″

Слайд 31input
ferrite
46 turns of ⅜″ superflex around five 1″ MN60 cores
1700

V →100 Ω
1200 V pulse → 50 Ω
500 V pulse

Слайд 32Heating 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:

Слайд 33Chopper: Summary
We have built prototypes for the necessary components for

the chopper: the pulser, meander structures, and combiner

The prototype

Слайд 34Aside: Application of Chopper R&D
to the current accelerator
Initially explored

Слайд 35Combining three DEI FETs
from DEI/IXYS RF
Use the same scheme as

HINS pulser,
combining three ~1kV → 16.7 Ω signals
(x

Слайд 36Plates: 0.9″
spacing
W1
Notching Plates in 750 keV line (H-)

Слайд 37In 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 =

Слайд 38Robyn Madrak - FNAL APT Seminar - 12/16/2008
Part II –

Слайд 39HINS 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

Слайд 40How it Works
In a coaxial line filled with some dielectric

(,
v = c/√
We vary  and thus v and phase

Слайд 41Robyn Madrak - FNAL APT Seminar - 12/16/2008
Operates in full

reflection mode (end is shorted)

Use solenoid along with shifters: phase

Слайд 42Modulates phase and amplitude independently:

With  = (2 - 3)/2

Слайд 43Two 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

Слайд 44Shifter Design Details
Center conductor: shrink fit during assembly

Use

quarter wave matching section
(for 50Ω)

Outer conductor has 0.020″ slot

Слайд 45Other 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

Слайд 46useful 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

Слайд 47Small Signal Frequency Response
Open loop bandwidth: 15 kHz
> 35 kHz