The FAIR Antiproton TargetThe FAIR Antiproton Target
B. Franzke, V. Gostishchev,
K. Knie, U. Kopf, P. Sievers, M. Steck
• Production Target
• Magnetic Horn (Collector Lens)
• CR and RESR
• Radiation Protection
Creation of antiprotons (p or pbar) Creation of antiprotons (p or pbar)
p, > 1 GeVp, > 1 GeV
m = E / c²mp = mpbar 1 GeV / c²
p
p
pbar
p
p, > 6 GeV p at rest
m = E / c²
p
p
p
pbar
__
Creation of antiprotons (p or pbar) Creation of antiprotons (p or pbar) __
0
0.00001
0.00002
0.00003
0.00004
0.00005
0.00006
0.00007
0 2 4 6 8 10 12 14 16 18 20
p [GeV/c]
d(p
_bar
/p)/
dp
(ar
b.
un
its)
120 GeV (Fermilab)
90 GeV (SIS300)
70 GeV
50 GeV
29 GeV (SIS100)
20 GeV
10 GeV
p = 3.82 GeV / c, E = 3 GeV, Bρ = 13 Tm
FAIR / CERN / FNAL pbar SourcesFAIR / CERN / FNAL pbar Sources
CERN (AC+AA) FNAL
E(p), E(pbar) 25 GeV, 2.7 GeV 120 GeV, 8 GeV
acceptance 200 mm mrad 30 mm mrad
protons / pulse 1 - 2 × 1013 ≥ 5 × 1012
pulse length 5 bunches in 400 ns single bunch 1.6 µs
cycle time 4.8 s 1.5 s
FAIR / CERN / FNAL pbar SourcesFAIR / CERN / FNAL pbar Sources
cycle time 10 s (cooling time in the CR)overall pbar yield: 5 × 10-6 pbar/p (based on CERN data) → 1 × 107 pbar/s
Increases the pbar yield by 50 %
FAIR Collector ring will be operated at h = 1, CERN ring was operated at h = 6
Time needed for stochastic cooling in CR (AC), upgrade possible
FAIR CERN (AC+AA) FNAL
E(p), E(pbar) 29 GeV, 3 GeV 25 GeV, 2.7 GeV 120 GeV, 8 GeV
acceptance 240 mm mrad 200 mm mrad 30 mm mrad
protons / pulse ≥ 2 × 1013 1 - 2 × 1013 ≥ 5 × 1012
pulse length single bunch (50 ns) 5 bunches in 400 ns single bunch 1.6 µs
cycle time 10 s 4.8 s 1.5 s
pbar Distribution After the Targetpbar Distribution After the Target
R.P. Duperray et al., Phys. Rev. D 68, 094017 (2003)
ppbar = 3.82 GeV/c ± 3%
From ~ 2.5 × 10-4 pbar / (p cm target) ~ 5 × 10-6 (or 2 %) are "collectable"
z / cm
y / c
m Ep = 29 GeV
MARS Simulation of the pbar YieldsMARS Simulation of the pbar Yields
-150
-100
-50
0
50
100
150
-50 -40 -30 -20 -10 0 10 20 30 40 50
x [mm]
x' [
mra
d]
after target
acceptance of separator
p = 3.82 GeV/c Dp/p = ± 3%
reaction products
B 1/r
primary beam does not hit the horn
Collecting pbars: Magnetic HornCollecting pbars: Magnetic Horn
CERN ACOL Horn, I = 400 kA
Collecting pbars: Magnetic HornCollecting pbars: Magnetic Horn
target beam axis magnetic field area
Collecting pbars: Magnetic HornCollecting pbars: Magnetic Horn
MARS Simulation of the pbar YieldsMARS Simulation of the pbar Yields
-150
-100
-50
0
50
100
150
-50 -40 -30 -20 -10 0 10 20 30 40 50
x [mm]
x' [
mra
d]
after targetafter hornacceptance of separator
p = 3.82 GeV/c Dp/p = ± 3%
yield =pbars in the ellipse
primary protons
MARS Simulation of the pbar YieldsMARS Simulation of the pbar Yields
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
1.4E-05
1.6E-05
1.8E-05
2.0E-05
2.2E-05
2.4E-05
2.6E-05
2.8E-05
3.0E-05
3.2E-05
3.4E-05
3.6E-05
3.8E-05
4.0E-05
4.2E-05
4 6 8 10 12 14 16 18 20
target length [cm]
yie
ld [
pb
ar/
p]
after target, dp/p<3%, theta<80mrad
Ir, d=3, rms=0.1
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
1.4E-05
1.6E-05
1.8E-05
2.0E-05
2.2E-05
2.4E-05
2.6E-05
2.8E-05
3.0E-05
3.2E-05
3.4E-05
3.6E-05
3.8E-05
4.0E-05
4.2E-05
4 6 8 10 12 14 16 18 20
target length [cm]
yie
ld [
pb
ar/
p]
after target, dp/p<3%, theta<80mrad
Ni d=3, rms=0.62
Temperature Increase in the TargetTemperature Increase in the Target
100
1000
10000
0 0.5 1 1.5 2 2.5
beam width (s) [mm]
Max
imu
m T
emp
erat
ure
incr
ease
D
T [
K]
DT = 360 K × w-1.68
DT = 310 K × w-1.68
DT = 2100 K × w-1.35
IrCuNi
melting of Ir
melting of Ni
melting of Cu
Fluka simulation
2×1013 protons per pulseGaussian beam profile
29 GeV/c, r = 1 mm (s)
0.00
0.02
0.04
0.06
0.08
0.10
0 1 2 3 4 5 6
z [cm]
(dE
/dm
) max
[Ge
V/(
pri
m g
)]
Ir Cu/Ni
cIr = 130 J kg-1 K-1
cCu = 385 J kg-1 K-1
cNi = 440 J kg-1 K-10.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
1.4E-05
1.6E-05
1.8E-05
2.0E-05
2.2E-05
4 6 8 10 12 14 16 18 20
target length [cm]
yiel
d [
pb
ar/p
]Ni/Cu, d=3, rms=0.62
Ir, d=4.5, rms=1
CR: Bunch Rotation and CR: Bunch Rotation and Stochastic Pre-CoolingStochastic Pre-Cooling
E
t
bunch rotation
adiabatic debunching
stochastic cooling
DE/E = ± 3 % ± 0.75 % ± 0.5 % ± 0.1 %
50 ns
stack core stack tail
Cross section throught the vacuum chamber at the momentum pick-up
stochastic coolingfor stack core
RESR: Antiproton AccumulationRESR: Antiproton Accumulation
stack core stack tail
160 mm (p/p = 0.8 %)
stochastic coolingfor stack core
partial apertureinjection kicker
injected beamfrom CR
acceleration by HF
(not in resonance with stack)
Antiproton AccumulationAntiproton Accumulation
stack core stack tail
160 mm (p/p = 0.8 %)
stochastic coolingfor stack core
stochastic coolingfor beam deposit
(high amplification)
Antiproton AccumulationAntiproton Accumulation
stack core stack tail
160 mm (p/p = 0.8 %)
stochastic coolingfor stack core
Antiproton AccumulationAntiproton Accumulation
stack core
160 mm (p/p = 0.8 %)
deceleration by HF
Antiproton AccumulationAntiproton Accumulation
stack core
160 mm (p/p = 0.8 %)
extraction kicker
Antiproton AccumulationAntiproton Accumulation
FAIR / CERN / FNAL pbar SourcesFAIR / CERN / FNAL pbar Sources
cycle time 10 s (cooling time in the CR)overall pbar yield: 5 × 10-6 pbar/p (based on CERN data) → 1 × 107 pbar/s
Increases the pbar yield by 50 %
FAIR Collector ring will be operated at h = 1, CERN ring was operated at h = 6
Time needed for stochastic cooling in CR (AC), upgrade possible
FAIR CERN (AC+AA) FNAL
E(p), E(pbar) 29 GeV, 3 GeV 25 GeV, 2.7 GeV 120 GeV, 8 GeV
acceptance 240 mm mrad 200 mm mrad 30 mm mrad
protons / pulse ≥ 2 × 1013 1 - 2 × 1013 ≥ 5 × 1012
pulse length single bunch (50 ns) 5 bunches in 400 ns single bunch 1.6 µs
cycle time 10 s 4.8 s 1.5 s
cycle time 10 s (cooling time in the CR)overall pbar yield: 1 × 10-5 pbar/p (based on CERN data) → 2 × 107 pbar/s
Target StationTarget Station
Target Exchange (target on air!)Target Exchange (target on air!)
Target StationTarget Station
Dose rates around the pbar targetDose rates around the pbar target
170 m
Fluka input, top viewFluka input, top view
air concrete irongraphite vacuum
Super
NESR
FRS
SIS18
CRRESRatomic physics
targetfrom SIS 100
Equivalent dose rates during operationEquivalent dose rates during operation
Equivalent Dose rate [Sv/h],2 × 1013 protons per pulse, 0.1 Hz
Induced Activity after Shut-DownInduced Activity after Shut-Down
airplane at 12000 m
Induced Activity after Shut-DownInduced Activity after Shut-Down
vertical section 4 m downstream of target
air concrete iron
SummarySummary
• Yield (target / horn / separator): 11 cm Ni-target, copy of CERN horn ~ 2 × 10-5 pbar per primary proton (4 × 107 pbar / s)
• Yield (out of RESR): ~ 1 × 10-5 pbar per primary proton (2 × 107 pbar / s)
• No significant increase of this number can be expected with another type of collector like a Li-lens.
• time averaged, less than 1 kW is deposited in the target higher repetition rate should be no problem
• Radiation protection: no principal problems up to now