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Longitudinal distribution of 3 removing (red), circulating (green) and survival at notching (blue) bunches, and long (1.08m) and short (0.54m) notchers waveform at Long-13, and 1.08-m notcher waveform for Long-05 straight section. December, 2011 A.Drozhdin
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Booster Beam Notching PMG Meeting
Salah ChaurizeAugust 21, 2013
Notching History• Notching is controlled removal of selected proton bunches
to facilitate a gap in the beam.• This gap allows the Booster extraction kickers magnetic
fields to reach full value to allow extraction of the remaining bunches.
• Without the gap or “notch” in the beam, the extraction kickers would displace these bunches in a non-controlled fashion causing losses in the extraction region
• In the past “notching” was less critical due to lower beam intensities and lower beam duty cycles. Losses were tolerable.
Longitudinal distribution of 3 removing (red), circulating (green) and survival at notching (blue) bunches, and long (1.08m) and short (0.54m) notchers waveform at Long-13, and 1.08-m notcher waveform for Long-05 straight section.
December, 2011 A.Drozhdin
The Notch/Gap3 Bucket Notch Width
non-cogged Cycle Notch @ 400MeV Cogged Cycle
Notch @ ~700MeV
Extraction Loss
Gap
Booster Kicker Notching Plans
• Phase I– Create a Horizontal Notch scheme to deposit beam at L13 using existing
Notching magnet systems.– Reduce losses to sensitive locations such as gradient magnets and RF
cavities.– Phase I is complete.
• Phase II– Improve notch kicker rise time to allow cleaner gap clearing and emmittance
growth of bunches adjacent to the cleared bunches.– Build new short kickers and fast pulser to drive faster notch producing
system.– Magnets building in progress. Kicker power system building underway. – Phase II is in progress.
Notching Pre-Shutdown 2012– A 3 bucket gap is created using two kickers located at Long 5
and Long 12• Notcher – A High Voltage(55kV) Kicker at Long 5• Noker - Lower Voltage Kicker (20-40 kV) at Long 12
– Used to clean out remnant notched beam in bucketsAt ~700 MeV due to Cogging operations.
– Beam is kicked vertically into Gradient Magnet dipoles at L5 and L12. Some notched beam reaches the collimator region at Long 6 and beam pipe mask at Long 13. This is not optimal
– Non-cogged notched cycles occurs at ~400 MeV.– Cogged notch cycles occurs at ~700 MeV.
Notching Magnets at Long 5 and Long 12 Pre-Shutdown 2012
Notcher
Hor. Pinger
De-commissioned Horz. Pinger
Ver. PingerNoker
MKS04
Beam direction
L12 Pre-2012 Shutdown L5 Pre-2012 Shutdown
Beam direction
December, 2011 I.Tropin
Residual dose profiles, vertical cross section (30 days irradiation/1day cooling, mSv/hr).
Vertical notcher
Notching at Long 5 Pre-shutdown
Booster Kicker Notching Plans
• Phase I– Create a dedicated region to deposited 3 bunches of beam to produce
a extraction kicker rise time gap.– Use current CX1168 thyratrons and PS systems to drive 3 kickers that
kick Horizontally rather than vertically. – We implemented a three kicker system to go into Long 12 and Long 13
as the absorber regions.– This first phase is completed. Notched beam has been achieved with
this new horizontal configuration. – Further orbit tuning and timing adjustments will continue as we
commission MI beam.
Horizontal position of 3-σ circulating beam and removed beam at notching for magnetic field of two horizontal notchers of B=67Gauss at 400 MeV (top) and
two notchers of B=72.5Gauss plus one notcher of B=35.2Gauss at 700 MeV (bottom).
Three horizontal notchers at Booster Long-12 with beam dump at Long-13 straight section.
August, 2011 A.Drozhdin
Three notchers with field of B=62 Gauss. The aperture of Short-12 straight section should be increased to R>86mm to eliminate losses. This can be done by displacement of R66.5mm aperture (without BPM) by dX=20 mm. [46.5-86.5]mm
Y
Short-12
dX=70mm
400MeVCirculating beam
3σ (ε=18π)
Dump-13
X Red – 30π, green - 18 π
August, 2011 A.Drozhdin
Long-13: Loss SimulationsDecember, 2011 I.Tropin
Side view
Top view
Reason to redesign S12 Spool piece
• Need to kick beam horizontally at L12 to create a notch in the beam.
• Horizontal aperture is current 4.5 in at S12• Maximum aperture through Booster Short
Corrector is about 5 in. • Current aperture restriction at S12 is BPM plates
and upstream and down stream bellows which are all 4.5in.
Reason to redesign S12 Spool piece
• New Extra Wide aperture BPM will give us 5 in aperture with new spool.
• New spool would use original spool design without the standard BPM components inside and larger aperture spool bellows
Extra Wide Aperture BPM
Short 12 Corrector Spool Upgrade
New 5” Aperture Spool Standard aperture 4.5 Inch
New Extra wide BPM Standard BPM inside
Notching Post ShutdownPhase I
– A 3 bucket gap is created using three Long kickers located at Long 12
• 3 Notcher – High Voltage(46-54kV) Kickers at Long 12• Notcher PS converted to NOKA PS• Noker PS converted to NOKB PS• Built/Commissioned new NOKC PS mostly with parts on
hand.– Beam is kicked Horizontally into new absorber at Long 13 – Extra Wide Aperture BPM and Short Corrector Spool needed
to allow kicked beam horizontal displacement before reaching absorber.
– Non-cogged notched cycles occurs at ~400 MeV.(unchanged)– Cogged notch cycles occurs at ~700 MeV.(Unchanged)
L12 Post Shutdown
NOKCMKS04
NOKBNOKA
12-13 sections of Booster tunnel.
Long-13
Long-12
Kick at L12 to Aisle.
Long 13 Notched beam absorber
Beam direction
Before
After
Long 13
Beam direction
Long 13 Actual new absorber
Current ConfigurationIn East Gallery
NOKA
NOKB
NOKC
Current Configuration In East Gallery
NIM Gate Modules Altera Based
CAMAC Controls and Ramp Cards
LeCroy Delay modules & CAMAC Trigger
Notching turned On and OffExtraction loss monitor
Notching off
Notching on
Beam Charge
400 MeV Notched beamAbsorber in operational position
400 MeV Notched beamAbsorber Retracted
700 MeV Notched beamCurrently
Preliminary Results and Commissioning
Phase II• Current BKED (Long) design kicker have a rise time of about 35ns • Short BKEF kicker modules are about half as long. They will
produce a rise time of about 25ns.• The voltage propagation time through the short kicker is cut from
20ns to 10ns due to half length.• Two short kickers will rise faster with appropriate pulser to reach
a desired flatop value.• We will use a ANU style pulser using a CX2610 hydrogen thyratron
rather than the existing CX1168 tube. This new pulser we gain us about 8-15ns of rise time.
• One Pulser can drive 4 magnets, possibly 6.
Phase II
• C. Jensen and J. Biggs along with EE support group is currently working on acquiring and building an ANU style pulser.
• Pulser components will be built through out 2013.
• We hope to have one pulser operating in a test configuration by the end of 2013.
• We will try to convert one long kicker to a pair of 2 short kickers as soon as feasible(2013/14)
C. Jensen
New Short kicker PS RackFront/Back view
EE Support currently building System
New Pulser for Short BKEE/BKEF Kicker Example(ANU Pulser Test Unit)
1Long Kicker BKED Series
2 Short Kicker BKEE Series
Conclusion
• Horizontal Beam notching is working.• Estimated notched beam power max is about
250watts which is half the budgeted power loss for Booster. The New L13 notched beam Absorber gives us 50% more head room on lost beam power. This helps towards future 15Hz. Operations
• Phase II should give us further improvements towards 15Hz. Operations.
Thanks to:-L13 Notched Beam Absorber Assembly-
PPD Experiment Fabrication- L13 Absorber Build and AssemblyD.Erickson, J. Judd, W. Blaszynski, W. GatfieldV. Sidorov - L13 Absorber Mechanical Design
APC Energy Deposition Simulations by- N.Mokhov, I. Tropin, S.Drozhdin M. Coburn L13 Absorber Motion Controls
-L12, S12, L13 Upgrade Support-Mechanical Support/ Instrumentation Groups – L13/S12 BPM and Corrector
R. Reily, B. Ogert, J. Kubinski, J. Briney ,D. Wallace, J. FitzgeraldControls Group CAMAC modules
Booster Techs - Power supply and load reconfiguration New timing module build and support electronics R. Mraz, T. Boes, D. Dick
Operations - Database work , O. Marshall, R. JonesAMG-L12, S12,L13 alignment
Radiation Safety – Joel FulghamConsultation – J. Lackey, B. Pellico
Machine Shop, Welding ShopMany More I missed
END
Reserve Slides
Looking upstream towards L13
Before After
Short Kicker/ Power Supply Effort
• Purpose of short kicker is to reduce kicker magnet rise/fill time.
• We can improve rise time of magnet field from current ~32nsec to about 25nsec.
• This will improve beam bunch removal with reduced disturbance of bunches intended for extraction.
New Short Kicker Pulser Control and PS racks location. East Booster Gallery
BKEE02(Short Module)Voltage ~40kV
BKED012(Long Module)Voltage ~40kV
BKEE001Short42KV Noker
BKED012Long42KVNoker
Channel 1 V inChannel 2 VoutChannel 3 Load I
Preliminary finding is a 8-15 ns difference between ANU pulser and Operational Booster pulser(Slower)
Testing by Jensen, Chaurize