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planned ESR tests T. Faestermann T U München 15 Oct. 2008. EXL Heavy Ion Spectrometer similar for ILIMA, ELISe, AIC. what can be learned at ESR? on the basis of old proposal for the ESR. Test of the ESR as High Resolution Spectrometer for Knockout Reactions (E57).
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planned ESR tests T. Faestermann T U München 15 Oct. 2008 EXL Heavy Ion Spectrometersimilar for ILIMA, ELISe, AIC what can be learned at ESR? on the basis of old proposal for the ESR
Test of the ESR as High Resolution Spectrometer for Knockout Reactions (E57) T. Faestermann, M. Böhmer, J. Friese, R. Gernhäuser, P. Kienle, T. Kröll, R. Krücken, L. Maier, K. Suzuki TU München T. Aumann, K. Beckert, P. Beller, F. Bosch, H. Emling, B. Franzke, H. Geissel, O. Klepper, C. Kozhuharov, G. Münzenberg, F. Nolden, A. Palit, C. Scheidenberger, M. Steck, T. Stöhlker, K. Sümmerer, H. Weick GSI Darmstadt H. Simon TU Darmstadt January 2004 withdrawn old Proposal
Knockout Reactions - example 450·A MeV 50Ca on 9Be => 49Ca @FRS - R3B type experiment huge cross sections 100 mb with g from ds/dP// => L-value of knocked-out nucleon g • from sto a specific state • C2S(j,n) needs: • shell model calculation • eikonal reaction theory without g inclusive Maierbeck et al., PLB nearly submitted
to be measured particle identification, residual nucleus dZ < 1 dA < 1 longitudinal momentum dP// ~ 20 MeV/c gamma coincidence e > 10% calorimeter old Proposal Proposal
Detector Ludwig Maier, thesis TUM sideview and topview old Proposal
alternatively: 2 detectors x,y,dE passive absorber ~ 4 mm Al ~ 2 detectors dE behind Energy loss in 0.4 mm intervals of Si ATIMA E/A=140 MeV 57Co 57Ni 58Ni single detector: dE = 2% => easy identification old Proposal Proposal
Horizontal Trajectories in the ESR - 0.5% dBr - 1.0% - 1.5% gas target detector pocket for 58Ni => 57NidBr= -1.74% old Proposal Proposal
from H. Weick new pocket C. Brandau Where is a waist? ±7mrad ±2.5mm pocket no waist waist waist Dispersion is there an ESR tuning where waist is accessible? if we cannot put the detector at a waist, => we have to do tracking
ESR „spectrometer mode“ (preliminary“) position of particle detector larger dispersion <-> smaller acceptance stable orbit, but injection? from C. Brandau
1 mm mrad from C. Brandau
Foil Detector B-field parallel to E-field: Shapira et al., NIM A 454 (2000) 409 with additional field gradient for our application an external field preferred, i.e. Helmholtz etc.) from C. Brandau
Tracking Detector in ESR drives and vacuum pockets are being prepared at KVI from H. Weick
Tracking Detector in ESR drives and vacuum pockets are being prepared at KVI but: chamber contains magnetic shielding from H. Weick from H. Weick
Restrictions E < 150 ·A MeV because of limited number of detectors? no problem if dE measurement at end of range sufficient A > 90 because of momentum acceptance? limited acceptance in high-dispersion mode => e.g 112Sn Only n-knockout? no, if outside detector could be used No gamma coincidences? not high efficiency in ESR, but calorimeter in NESR Outlook Annihilation of antiprotons on nuclear surface in NESR-collider
Example Dispersion: 9m Acceptance: Dp /p = ± 1.5 · 10-2 400 A MeV 112Sn => p = 107 GeV/c 111Sn shift => 1/112 · 9 m = 80 mm Dp= ± 300MeV/c => Dp /p = ±2.8 10-3 => Dx = ± 25 mm a = 2.8 mrad 1mm image => dp /p = 1mm / 9m = 1.1 · 10-4 dp = 12 MeV/c
What can be tested? Detector: Z identification A identification (dE near Bragg peak) passive absorber? Momentum resolution: spectrometer mode of ESR Tracking: detector in front of 1st dipole could a foil detector serve for tracking? 1) stable beam => 2) abundant fragment Simultaneous test experiment close to gas target Only parasitic beam is needed
What would we ask for? • development time for modified ESR mode some time in 2009 • develop tracking detector for UHV and build ID-telescope in pocket • real experiment with medium heavy beam together with another EXL test for vacuum early in 2010
Rates etc. Assume 108 stored 58Ni ions (1.5 MHz corr. to 0.7 mA) in 1 halflife an ion sees 2400s 1.5x106s-1 3x1013 H atoms /cm2 = 1023 H atoms /cm2 a typical solid target 0.5 g/cm29Be has 3x1022atoms /cm2 Proposal