ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Fermilab Proton Source ReportBob Webber
ICFA Mini-Workshop on High-Intensity,High Brightness Hadron Beams
Beam Halo and ScrapingLake Como, WI
9/14/99
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Fermilab Linac Parameters
� 200 MeV proton Linac built ~ 1969� H- upgrade in 1977� 400 MeV upgrade in 1992� 15 Hz hardware capability, variable beam pulse rate� 45mA pulse current typical at 400 MeV� variable beam pulse length, typically 10-30 microsec� typical efficiency 10 MeV to 400 MeV ~ >95%� typical operation ~ .5µA for 0.2kW� present normal 400 MeV capability ~ 20 µamp for 8kW
� 45mA @ 15 Hz @30 microsec
� accelerated >90mA (protons) during Jan. 1999 test
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Linac Toroid and BLM Plot
DTL CCL
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Linac Radiation Survey Data
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
2 4 O
ut
2 4 In
2 3 O
ut
2 3 In
2 2 O
ut
2 2 In
2 1 O
ut
2 1 In
1 4 O
ut
1 4 In
1 3 O
ut
1 3 In
1 2 O
ut
1 2 In
1 1 O
ut
1 1 In
Va c V
a lve
BLD
Up
V O
ut
V In
B O
ut
B In
5 Ou t
Ta n k 5
InT
a n k 4 O
u t5 8
De g .
05 0
1 0 01 5 02 0 02 5 03 0 03 5 04 0 04 5 0
5 4O u t
5 4 In 5 3O u t
5 3 In 5 2O u t
5 2 In 5 1O u t
5 1 In 4 4O u t
4 4 In 4 3O u t
4 3 In 4 2O u t
4 2 In 4 1O u t
4 1 In 3 4O u t
3 4 In 3 3O u t
3 3 In 3 2O u t
3 2 In 3 1O u t
3 1 In
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
7 4 O u t 7 4 In 7 3 O u t 7 3 In 7 2 O u t 7 2 In 7 1 O u t 7 1 In 6 4 O u t 6 4 In 6 3 O u t 6 3 In 6 2 O u t 6 2 In 6 1 O u t 6 1 In
Four typical surveys between 12/94 and 3/96, readings are �on contact�several hours after beam off, running typically at 1-1.5 E16 per hour
750KeV
400 MeV
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Linac Radiation and Activation Issues
� Linac radiation limits� several interlocked detectors for accident conditions� trips rarely encountered
� Linac activation� not a serious issue at typical levels� 400MeV �switchyard� is important
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Fermilab Booster Parameters
� 400 MeV -- 8 GeV proton synchrotron built ~ 1970� 15Hz sinusoidal magnet cycle with transition at γ = 5.4� H- charge exchange injection, typically <12 turns� adiabatic capture of injected beam by Booster RF� 38 - 53 Mhz RF frequency, h=84� typical 8 GeV beam current ( 1E16 pph = 0.44 µA )
� historical high 3E12ppp @ 2.5Hz ~ 1.3µA for 10kW (8 GeV)� currently 2E12ppp @ 0.5Hz ~ 0.16µA for 1.3kW� Run II demand (2000) 5E12ppp @ .7 Hz ~ .55µA for 4.3kW� Year 2002 demand 5E12ppp @ 8 Hz ~ 6.4µA for 51kW
� typical efficiency 80% @ 1E12ppp to 60% @4E12ppp
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Booster Low Intensity Charge Snapshot
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Booster High Intensity Charge Snapshot
Digitizersaturation
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Booster Radiation and Activation Issues
� Fermilab HEP program, within the coming year, will belimited by allowed radiation around Booster
� demand for proton throughput will rise order of magnitude innext three years relative to historic levels in 90�s
� recent office and beamline constructions and tightenedradiation exposure regulations exacerbate original situation
� little option for additional shielding
� Component activation will be a serious concern atNUMI/MiniBooNE levels
� Booster beam loss reduction and control key to entirefuture planned Fermilab high energy physics program!
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Booster Ring Radiation Survey24 hrs after extended running
at 7.5E15/hr
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Booster Extraction AreaSurvey 24 hrs after extended
running at 7.5E15/hrReadings are mR/hr @ 1 ft.
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
1998 Booster Shielding Assessment
� Driving factors� old assessment inadequate for anticipated proton requirements� re-location of extraction point for beam to Main Injector� old assessment relied on loss signature at few locations
limiting machine development flexibility, e.g. high energyorbit changes and magnet moves
� Numerous soil activation measurements� Complete shielding geometry assessment for entire ring� Many measurements to understand radiation patterns
and levels for �normal� and �accident� conditions� Resulted in array of ~50 interlocked radiation detectors
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Typical Booster Lattice Period and Apertures
Defocus DefocusFocus Focus
Short StraightLong Straight
65 feet
Physical Aperture (inches) R Value (cm1/2)
Location Horizontal Vertical Horizontal Vertical
Short-straight (BPM) 4.5 4.5 0.197 0.501
F-magnet (short-straight end) 4.5 1.64 0.197 0.181
F-magnet (D-magnet end) 8.0 1.64 0.457 0.126
D-magnet (F-magnet end) 8.0 2.24 0.467 0.164
D-magnet (long-straight end) 3.25 2.24 0.294 0.126
Long-straight (Beam pipe) 3.25 3.25 0.334 0.185
Long-straight (RF or Kicker) 2.24 2.24 0.231 0.128
Long-straight (Dog Legs) 2.31 3.25 0.237 0.185
Long-straight (Injection) 2.56 2.56 0.264 0.146
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Booster Shielding at Period Long 9
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Injection Energy Radiation Patterns400MeV Losses at L9 and S9
(Normalized to 1.35E17 protons/hour)
0.00
10.00
20.00
30.00
40.00
50.00
0 6 12 18 24 30 36 42 48 54
14.8 : 1.2
14.0 : 11.5
12.4 : 20.0
5.6 : 24.0
5.0 : 208.0
L9 : S9 BLM's
Feet
mrem/hr
Long Straight Short Straight
Measured radiation levels at surface above Period 9 for different BLM ratios whileattempting to lose all beam with dipole correctors.
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Energy Dependent Loss PatternsEnergy Dependent Losses
(Normalized to 1.35E17 protons/hr)
0
500
1000
1500
2000
0 20 40 60 80 100 120 Feet
mrem/hr
7.9 GeV
7.1 GeV
6.0 GeV
4.9 GeV
3.8 GeV
3.1 GeV
2.1 GeV
1.1 GeV
0.5 GeV
S6 S7L7L6
M easured radiation levels above periods 6 and 7 at different beam energiesobtained by shutting off RF while accelerating.
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Booster Interlocked Radiation Detectors
West Fan Room
Booster Interlock Detector Locations
West Booster Tower
East Booster Tower
Linac Gallery
Extraction Gallery
MI8 LineWest Booster Gallery
East Booster Gallery
Booster Portakamps
Minimal Occupancy Buildings
Tunnels
Stairwells and Labyrinths
Unlimited Occupancy Buildings
L1L2
L3
L4
L5L6
L7
L8
L9
L10
L11
L12L13
L17L18
L19
L23
L14
L24
L16
L22
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
Indoor detector
Outdoor detector
Buried detector
In Transformer Cabinet
S12
S13 S14
S16
(LLRF Room) S17
S18(BPW-105)
(BPW-109)
L20(BPW-117)
S19
(BPW-109)
(CUB Utility Tunnel)
S20
L21(BGW-125)
S21Luminosity Upgrade
Room( )
S22
S23S24
S1(Period 1 Labyrinth)
(East Booster Fan Room)
Note: Booster Long 11 detector is located inside Brenford #3. Booster Short 19 is located in the CUB Utility Tunnel on the West side of the LCW Piping. Booster Short 12, located in the East Booster Fan Room, requires an AC-33 key. Booster Long 21, located in BGW-125, requires an AC-2 key. Booster Short 21, located in the Luminosity Upgrade Room, requires an AC-2 key. Booster Long 7 located in a manhole in the road between the Booster Towers. Booster Long 2 detector is located in the YBW1 transformer cabinet. The 8 Gev Line Sarecrow is located in the Tev enclosure.
8 Gev Scarecrow
Tev Enclosure
For 8 Gev Extraction Losses
For 8 Gev Extraction Losses
L15S15
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Causes of Beam Loss
� Poor orbit control� closed orbit changes dramatically vs. time in cycle� low field orbit is regularly modified by normal tuning� small dynamic apertures
� Historically no beam gap synchronized to extractionkickers -- systematic 2% beam loss at extraction septum
� Longitudinal instabilities after transition at high current� RF capture inefficiencies� Space charge blowup ?� ??
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Toward Control and Solution to Problem
� Continued aperture improvements� magnet moves to remove aperture constraints� study increased RF cavity aperture� improved orbit control
� orbit adjustment program� ramped correctors w/ beam position feedback� improved main magnet control
� Create and synch beam gap with extraction kicker� presently able to create notch at 400 MeV after injection with
short kicker� investigating laser neutralization gap creation� synchronization to circulating Main Injector beam is
complicated and narrowly constrained by beam dynamics
ICFA Beam Halo and Scraping Workshop9/14/99
f Proton Source Department
Toward Control and Solution to Problem
� Improved longitudinal dampers� Scraper/collimator
� control loss of particles that cannot be retained� design is commencing based on new Booster model
� New BLM transducer and data acquisition system� ability to quantitatively see and record when and where beam
losses occur under complicated operating scenarios is essentialto facilitate and measure progress