Transcript Intro talk - Science and Technology Facilities Council

The ISIS Dual Harmonic Upgrade
Andy Seville
Joint Accelerator Workshop
The Council for the Central Laboratory of the Research Councils
March 28th, 2006
ISIS Dual Harmonic Acceleration
Single Harmonic
Dual Harmonic
P Error →
50% More Protons!
Voltage →
Enlarge Stable Region
Optimise trapping
Reduce Loss
Add 2nd Harmonic
RF Component
RF Phase →
RF Phase →
ISIS Dual Harmonic Acceleration
200
The required Accelerating Field
is given by
RF Volts (kV)
150
1RF volts
100
V = Vo (sin  - .sin (2+ ) )
2RF volts
The voltage on Cavity Gaps is
V = -Vo sin () + .Vo sin (2 + )
50
0
-2
0
2
4
6
8
where Vo and  are +ve.
10
Time (ms)
60
40
(Deg)
20
0
theta
phis
-20
-40
-60
-80
-2
0
2
4
Time (ms)
6
8
10
 and  chosen to minimise
loss during injection, trapping
and acceleration cycle
ISIS RF Systems - Overview
13kVpk at 12 1RF accelerating gaps
+10kVpk at 8 2RF accelerating gaps
ISIS Dual Harmonic Acceleration
Changing Bias Current changes
inductance of ferrite & therefore
resonant frequency of the cavity.
Every 20ms:-
Injection
Extraction
Proton Energy
70MeV
800MeV
Rotation Freq
0.65 MHz
1.55MHz
1RF Freq
1.3 MHz
3.1 MHz
2RF Freq
2.6 MHz
6.3 MHz
Bias current
200 A
2000 A
2RF System Schematic
Beam Compensation Loop
Cavity Tuning Loop
Phase Loop
ALC Loop
LPRF Controls: Amplitude,
Phase & Cavity Tuning
Bunch
Length
Loop
Trim
Function
Frequency
Law
Summing
Amplifier
Frequency
Law
Generator
Dipole
Search
Coil
Beam
Phase
Loop
Master
Oscillator
Frequency
Doubler 2.6
MHz – 6.2
MHz
1.3 MHz 3.1 MHz
Sum
Electrode
Radial
Loop
Existing Fundamental RF
System
1RF
Anode Power Supply
2nd Harmonic Beam
Compensation Loop
LPF
Func.
Gen.
Variable
Delay
Func.
Variable
Gain
Gen.
Cavity Bias Regulator
Low Voltage Power Supply
2RF
Driver Amplifier
To Other 2nd Harmonic
Cavity LPRF Systems
 Phase
LPRF
Shifter
Super-
Phase
2
period
Controls:
Amplitude,
Modulator
Phase
Func
Gen.
Summing
Amplifier
RF Level
Controller
Splitter
HPD
Cavity
2nd
Harmonic Cavity
Voltage Loop
2nd Harmonic
Cavity Tuning
Loop
2nd Harmonic Cavity
Phase Loop
RF
Detector
2
Cavity
Lock LPF
RF
Func.
Gen
Phase Modulation and Delay Chassis
Phase
Detector
(Cavity
Lock)
Digital Signal
Processor
A single Burle 4648VI
tetrode is used to drive the
2RF cavity
Limiters
2
Cavity
Lock
Servo
Phase
Detector
(Cavity
Tune)
Gated
Summing
Amplifier
2
Phase
Networks
RF
Summing
Amplifier
Delay
Unit
2nd Harmonic low power RF
Cavity Gap A
Voltage
Monitor
Cavity Bias Regulator
2nd Harmonic high power RF
PSU - Splat!
+ PSU Tripping
+ ISIS Schedule
+ Machine Downtime
2RF Commissioning - Preliminary Results
95%
93.5%
DHRF Acceleration beam intensity and beam loss (2 x 2RF Cavities)
Schematic of fundamental frequency
and 2nd harmonic RF lock loop
Fundamental System
Var.
Phase Mod
M. O.
az ±0/ 90
( = 0/-18/-
1 RF.
Cav.
 Trim
Cavity Lock
Phase Mod
 Det.
90
36)
 Ref.
A
Frequency
Doubler

Phase
Mod
2RF System
az±45
Phase
Mod
Var.
Cavity lock
Phase Mod
 Trim
2 RF.
Cav.
90
 Ref.
B
Simulated by Cable
Delay and Summing Amp
 Det.
ISIS 2RF System Phase Modulation
2RF5 Shifted For Azithmuthal
Position
1.0000
0.8000
Relative Volts
0.6000
0.4000
0.2000
1RF3
0.0000
2RF5
-0.2000
-0.4000
-0.6000
-0.8000
-1.0000
0
90
180
270
360
Phase (deg 1RF)
Phase offset for location of
each system around ring

2RF4
2RF5
2RF6
2RF8
Az
Shift
21.5
73.55
109.5
165.5
1RF
Phase
43
147.1
219
331
2RF
Phase
86
294.2
438
662
ISIS 2RF System Phase Modulation
10
Phase Detector
8
2RF4 Volts
6
10kV
2RF5 Volts
4
2
200V
0
-2
-4
-0.005
0.000
0.005
0.010
0.020
2RF4 test
6
2RF5 test
4
+90°
2RF5
0°
2RF4
-90°
2RF4 expt
2RF5 expt
2
F-Mod Volts
0.015
0
-2
-4
-6
8:1 reduction in combined
gap volts (simulated!)
-8
-5
0
5
Tim e (m s)
10
15
(SP4+SP5) / (SP4-SP5)
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.2ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.3ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.4ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.5ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.6ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.7ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.8ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 0.9ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 1.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 1.5ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 2.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 3.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 4.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 5.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 6.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 7.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 8.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 9.0ms
Animated Version?
N - protons
Dual Harmonic Pulses
DHRF Acceleration
with 3 x 2RF cavities
Beam Pulses
@ 9.5ms
Animated Version?
N - protons
Theta Phasing Results
APS Current (no beam) 7Apk
-72°
0°
2RF SP5 APS Current
SP4, 5 & 6 accelerating
Theta = 0
APS Current
(with beam) 5Apk
Theta
2RF SP5 APS Current
SP4 ,5 & 6 accelerating
Theta
Challenges
•
•
•
•
•
Solve Anode PSU tripping problem
Complete cavity phasing tests
DHRF Acceleration with all 4 2RF cavities
Run 2RF Cavities reliably
Increase beam current!