1 Advanced Algorithms All-pairs SPs DP algorithm Floyd-Warshall alg.
The way to fast and "loss-free" SPS kickers E. Gaxiola With contributions from AB-BT-KSL section...
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Transcript of The way to fast and "loss-free" SPS kickers E. Gaxiola With contributions from AB-BT-KSL section...
The way to fastand "loss-free" SPS kickers
E. Gaxiola
With contributions from AB-BT-KSL sectionand F. Caspers, T. Kroyer, M. Timmins, J.
Uythoven
Kicker Functional specification:
Fast rise- and fall-time very stable magnetic field pulse Rise-, fall-times: 200 ns to 1.1 μs Flattop ripple: 0.5 to 1% Induction field0.08 to 0.16 T
PS / SPS days – 13/01/2005
Limitations: Ferrite Curie temperature: Beam induced losses Beam impedance: Beam stability Maximum operating voltage Switches Maximum current Ferrite core saturation Bsat
Pulsed power Low impedance travelling wave magnet
Speciality magnets * Vacuum; * High voltage; * High currents
Today’s kicker systems Upgraded thyratron switch
performance Semiconductor components
applications Heat conductance cooling Reduced beam impedance
(longitudinal + transverse)Beam stability?!
Injection MKP 2001
4 batch LHC-type injection Modernisation/upgrade MKP systems #1 to #3
Impedance increase 12.5 Ω 16.7 ΩFaster rise timeImproved flattop ripple
PFN’s upgrade: Pulse fine tuning
2004 Rise time improvements for MKP system #4
2006 Final fine tuning (as was done for MKE)
Extraction MKE LSS4 2003
Magnet cooling for reduced beam induced heating Power semiconductor diode stacks
Increased reliability + lifetime(more cost efficient solution)from LHC MKD kicker generator development
2004 Shortened MKE Generator PFN lengths Optimized rise time PFN front cell adjustments
+ adjustable PFN first coil
Reduced kicker ripple Magnet damping resistors
Optimized fall time Mis-matched TMR values+ Use of SPS transverse feedback system (tested in SPS MD) CNGS double batch extraction practically within specs
The hardware limits of the present MKE kicker system are practically reached
Oct 2003 Step 1:As installed in 2003
0.0
5.0
10.0
15.0
20.0
25.0
Time [us]or%
1 2 3 4
Rise timeFall time
Usable batch timeOvershoot [%]
Kick pulse f lattop ripple [%]Post kick pulse ripple [%]
Subsequent improvement step
Pulse parameter
SPS MKE LSS4 pulse parameters
July 2004 Step 3:Mismatched TMR values
Nov 2004 Step 4:Fine-tuning adjustable PFN firstcoil for each MKE generator
April 2004 Step 2:Adding Magnet Damping Resistors+ PFN front cell adjustments
Tune kicker MKQH Beam impedance reduction Test bench
MKQH kicker magnet withceramic inserts withresistive layer coating
Proof of principle
2004 positive results for beam impedance
Approach I
Not applicable to MKE: Due to significantly increased rise time!
Horizontally: 8.2 sigma SPS beamVertically: 3.2 sigma SPS beam
Alumina plates withmetallic finger strips
Ferrite
High voltage conductor Ground electrode
Alumina profile with
Resistive coating
SPS kicker heating
0
20
40
60
80
100
120
20 30 40 50 60 70 80 90
Average MKE temp measured [ o C ]
Nor
mal
ised
kic
k am
plitu
des
[%]
MKE, p.u. BPH23209MKE, average p.u.'sMKE 16.10.03MKQH, 2003MKQH, 2004
Results MKQH kicker magnet
< 20042004
T*Curie reached at TMKE,reference= 45ºC >90ºC
Rise time 1-99%: 0.6 µs 2.9 µs
Results Impedance Measurements MKQH
Further improvements Studies underway
Capacitive coupling by using metallic finger type strips: Beam impedance reduction Im{Z} and Re{Z} Reduced heating via Re{Z}
2006 Machine implementation on one MKE magnet
(2 cells out of 7 cells)If successful: Possible full 9 MKE fast extraction kicker upgrade LSS4 and LSS6 for 2007 and beyond(in e.g. shutdowns)
Approach II
Horizontally: 8.2 sigma SPS beamVertically: 3.2 sigma SPS beam
Alumina plates withmetallic finger strips
Ferrite
High voltage conductor Ground electrode
Bypass-insert:
Double sided comb structure
Approach IIIStrips Printed Directly on Ferrites
Interdigital comb structure 20mm spacing
surface discharge
Results Impedance MeasurementsSingle Kicker Cell (Approaches II and III)
MKE / MKQH kickers 2004
Lab: Significantly reduced beam impedance! Reduced losses
Next step(s): 2005
Study vacuum high voltage breakdown discharge characteristicsTravelling wave kicker: To be X-checked
2006 SPS tests in LSS6
Summary Very useful knowledge build-up phase ’98 – 2006
New kicker diagnostics were added over the past years. Tests for SPS Complex Application 2003 – 2008
Confirmation of the positive impact of the upgrade of the injectors for LHC
“Old” recuperated equipment Upgraded “modern” performance.
This is only a preliminary summary of the findings.More extended analysis + documentation required.More detailed modelling Compare measurements and simulations. Proven solutions recommendations.CERN at the frontier: bigger and ….
Summary (continued) MKP: Rise time improvements done
Further simulations + tuning to be done Higher reproducibility needed Spare to be finalized with increased diagnostics
MKQH: Useful test-bed with proof of principle,not straight forward applicable to other kickersBeam impedance reduction realized
MKE: Further tests to be done with stripes for voltage holding, vacuum, pulse shape in 2006
beam tests Larger scale applications in 2007 …. 2008 ? If not successful New concept (Alternative new kickers, lots of $ +
my) MKE pulse specs: After lots of modifications (not possible for 2003 tests) now practically at their limit
together with damper practically fulfilling CNGS double batch specs(is damper use the definitive solution?)