the antiproton-ion collider ec, 500 kv nesr r. krücken technische universität münchen for the...
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The Antiproton-Ion Collider
EC, 500 KV
NESR
R. Krücken
Technische Universität München
for the
Antiproton Ion ColliderCollaboration
The Antiproton-Ion Collider
EC, 500 KV
NESR
• Why another technique for nuclear radii?
• The Antiproton-Ion collider
• Simulations and rate estimates
• Summary and Outlook
rnp from antiprotonic atoms
Neutron-skin thickness in Sn isotopes
(1&2) RHB/NL3(3) RHB/NLSH
(4) HFB/SLy4(5) HFB/SkP
(p,p)
(3He,t)antiprotons
M. Bender, P.H. Heenen, P.G. ReinhardRev. Mod. Phys. 75 (2003) 122
Why the antiproton ion collider?
• charge radii can reliably measured (Lasers, (e,e’))
• several methods available for matter / neutron radii (p,p), (,’), (3He,t) reaction cross section, antiprotonic atoms
• results are • not always consitent• partly model dependent
• We need a method that determines proton and neutron radii
• using the same method
• in the same experiment
• at the same time
• independently
Antiproton Ion Collider (pbarA)
Rate estimate• 109 stored antiprotons
• Luminosity of 1023 cm-2 s-1 for 106 stored ions
• Typical total absorption cross-section: 1 barn
0.1 counts per second 1000 counts in 3 hours 0.01 fm stat. accuracy of rnp
Additional equipment:• 70kV electron cooler RESR• 70kV electron cooler pbar-ring• transfer line RESR – pbar-ring
• Antiprotons collected in RESR
• cooled and slowed to 30 MeV
• transferred to pbar-ring(Ring design by Novosibirsk group)
Limits due to T1/2 >1s and production yield (>104)
T1/2 =1s
Example: Z = 28-50
Theoretical cross-sections
Calculations by H.Lenske
theoryfrom Cwith
2
2
2
ppR
nnR
pntotalR
rC
rC
rC
200 MeV
400 MeV300 MeV
0
20
40
60
80
100
120
0 5 10 15 20
sig
AB
S(b
) [m
b]
Impact Parameter b [fm]
Antiproton-Nucleus Partial Absorption Cross Section 78Ni
50 MeV100 MeV
At lower energies one is moresensitive to the periphery of the density distribution ( energy scan)
Theoretical calculations – example 58Ni
Lenske, Wycech
A A-1
p
impact parameter b [fm]
z=4fm
z=-4fm
Pmiss(z): probability that pions miss the residual A-1 nucleus
Pdh: probability that residual nucleusis cold (E*< Sn,p)
About 30% of produced A-1 nuclei survive
Nuclear density
Simulations of the reaction kinematics
About 30% of produced A-1 nuclei survive
132Sn 131In132Sn 131Sn
z
-0.0
075
0.0
128
132Sn
Acceptancelimit of NESR
A A-1
p
q
p
q
p
qpz
z00
Measured momentum distribution is consistent with quasi-free scattering
F. Balestra et al., NPA491, 541 (1989)
LEAR data on Ne
Measured momentum distribution gives insight into angular momenta of annihilated nucleons
Schottky method for identification and counting of A-1 nuclei
von P. Kienle
Simulated momentum distributions
40Ca
40Ca 39K40Ca 39Ca
72Ni 71Co72Ni 71Ni
132Sn
132Sn 131In132Sn 131Sn
72Ni
A~130:A & both A-1 nuclei in the acceptance Schottky method using one ring setting recoil detection
A~70:A & and one A-1 nucleus in the acceptance Schottky method using zwo ring settings recoil detection
A<60:A-1 nucleus not in the acceptance recoil detection
A A-1
p
z
Recoil Detection after NESR dipole section
Existing ESR detector (TUM)
5 m
0.5
m
+7%
-6%
Staged set of recoil detectors covers large momentum range
Luminosity measurementusing elastically scattered antiprotons
Ions Antiprotons
Elastic scatteredAntiprotons
InteractionRegion
LuminosityDetector
to EC
from NESR
elast
elastdNLdt
lab [degrees]0 1 2 3 4 5 6D
iff.
Cro
ss-s
ect
ion [
b/s
r]
106
104
102
detector
AIC physics program
• benchmarking: radii for the Sn isotopic chain • stable isotopes, measured with different techniques• plan: extending from 105Sn to 135Sn
• radii along other closed-shell isotopic and isotonic chains
• radii for nuclei near the drip-line in light nuclei• transition from halo nuclei to neutron skins
• behaviour of radii across a shape transition• e.g. from 80Zr to 104Zr
• Odd-even effects in nuclear radii
• study the antiproton-neutron interaction
Summary and Outlook
• antiproton-nucleus cross section at 740 MeV/u is proportional to <r2>
• detection of A-1 products allows • determination of proton and neutron radii• in the same experiment (same systematic uncert.)• in a model independent way
• AIC is feasible in terms of technology and physics output
• Simple counting experiment using Schottky method or recoil detectors (once the collider runs)
• AIC allows systematic investigation of • Neutron skins• Transition from halos to skins• Odd-even staggering in radii• Shape coexistence and its effect on neutron and proton
radii• Nucleon-antiproton interaction
Antiproton-Ion Collider Collaboration
• Spokesperson / Deputy: R. KrückenC / J. ZmeskalA
• Project Manager / Deputy: P. KienleC / L. FabbiettiC
Beller, Peter A
Bosch, FritzA
Cargnelli, Michael B
Fabbietti, Laura C
Faestermann, Thomas C
Frankze, Bernhard A
Fuhrmann, Hermann B
Hayano, Ryugo S.D
Hirtl, AlbertB
Homolka, Josef C
Kienle, Paul B,C
Kozhuharov, Christophor A
Krücken, Reiner C
Lenske, Horst E
Litvinov, Yuri A
Marton, Johann B
Nolden, Fritz A
Ring, Peter C
Shatunov, Yuri F
Skrinsky, Alexander N. F
Suzuki Ken, C
Vostrikov, Vladimir A. F
Yamaguchi, Takayuki G
Widmann, Eberhard B
Wycech, Slawomir H
Zmeskal, Johann B
Institute A, Gesellschaft für Schwerionenforschung, Darmstadt, Germany (GSI)Institute B, Stephan Meyer Institut, Vienna, Austria (SMI)Institute C, Technische Universität München, Munich, Germany (TUM)Institute D, University of Tokyo, Tokyo, Japan (UoT)Institute E, Justus-Liebig Universität Giessen., Giessen, Germany (JLU)Institute F, Budker Institute of Nuclear Physics, Novosibirsk, Russia (BINP)Institute G University of Saytama, Saytama, Japan.(UoS)Institute H, Andrzej Soltan Institute for Nuclear Studies, Warsaw, Poland (IPJ)