RITU and the new separator at Jyväskylä J. Uusitalo, J. Sarén, M. Leino RITU and γ-groups University of Jyväskylä, Department of Physics
RITU, Recoil Ion Transport Unit -Magnetic configuration Q v DQ h Q v -Maximum beam rigidity 2.2Tm - Bending radius 1.85 m - Angular acceptance 8 msr - measured with alpha source - Dispersion 10 mm/% of Bρ - Dipole bending angle 25 o - Total length 4.8 m
40 Ar + 175 Lu > 211 Ac + 4n E fr = 33 MeV q ave = 6.9 vert. acc. ± 26 mrad horiz. acc. ± 77 mrad Acceptance 8 msr
JUROGAM GREAT RITU
Nuclear Physics Group at Daresbury, University of Liverpool, Manchester University, University of Surrey, York University, Keele University MWPC PIN-diodes DSSSD Planar Ge Clover Ge TDR acquisition system
The GREAT detector system 2x 60mm x 40mm DSSD 28x 40mm x 40mm PIN Segmented planar Ge Compton-suppressed Ge clover Gas counters U.K. Universities & Daresbury Triggerless TDR DAQ system Presently at JYFL
A gas-filled recoil separator plan NIMB 204, 138 (2003) T. Enqvist et.al., 112 Sn( 86 Kr, 3n) 195 Rn @ 365 MeV 0, ± 26 mrad, 0, ± 1mm Dispersion 15 mm/%bρ
if Bρ difference 4 % between 195 Rn and beam 86 Kr, and ± 7 mrad for beam and ± 26 mrad for 195 Rn RITU QDQQ with 25 o dipole magnet DQQ with 50 o dipole magnet DQQ with 50 o dipole magnet, and B n = -4
The new JYFL vacuum mode separator Design, ion optics and Physics Matti Leino, Jan Sarén, Juha Uusitalo, RITU and GAMMA groups
Charged particle in electric and magnetic fields Magnetic rigidity: Bρ = mv q 2Tm q Electric rigidity: Resolving power: Eρ = pv q R = 2x 2T q ( x Δ) ( x x) 00 Deflection angles in electric field: α α ER p A A ER p q q ER p Universal: - Both electric and dipole fields are needed - Beam is dumped inside the first dipole (chamber) - Mass resolving power about 350 FWHM can be reached - Full energy beam suppression factor of 10 9-10 15 can be expected
Mass separators all around the world: some trends DRS: Q1-Q2-Q3-WF1-WF2-Q4-Q5- Q6-S1-S2-MD1-Q7-Q8-Q9 (13.0 m) CARP: Q1-MD1-H1-H2-ED1-H3-Q2 CAMEL: Q1-Q2-ED1-S1-MD1-S2-ED2 HIRA: Q1-Q2-ED1-M1-MD1-ED2-Q3-Q4 (8.6 m) JAERI-RMS: Q1-Q2-ED1-MD1-ED2-Q3-Q4-O1 (9.4 m) FMA: Q1-Q2-ED1-MD1-ED2-Q3-Q4 (8.2 m) EMMA: Q1-Q2-ED1-MD1-ED2-Q3-Q4 (9.04 m) JYFL new: Q1-Q2-Q3-ED1-MD1 (6.74 m) Q S H M O WF ED MD quadrupole sextupole hexapole multipole octupole velocity filter electric dipole magnetic dipole
Design principles and aberrations - Maximizing angular, mass and energy acceptance while minimizing geometric and chromatic aberrations. - The largest aberrations are (x δ 2 ), (x θδ) and (x θ 2 ). These are minimizedbyaddinga curvatureto the magnetic dipole entrance and exit. - Higher order aberrations found to be negligible.
Optical layout in floor coordinates
Angular focus in x- and y-directions X-direction, 5 angles: 0, ±15 and ±30 mrad Y-direction, 5 angles: 0, ±20 and ±40 mrad
Energy focus and mass dispersion in x-direction Energy deviation: 0, ±3.5 and 7.0 % 3 different angles 3 different energies 3 different masses Angles: 0 and ±30 mrad, Masses: 0 and ±1 % Energies: 0 and 7.0 %
Main properties of the new separator compared to FMA FMA JYFL new - Configuration QQEDMDEDQQ QQQEDMD - Horizontal magnification -1.93-1.58 - Vertical magnification 0.98-4.48 - M/Q dispersion -10.0 mm/% 8.1 mm/% - First order resolving power, 259 256 2 mm beam spot -Solid angle acceptance 8 msr 10 msr - Energy acceptance for central mass and angle +20 % - 15 % +20 % - 15 % - M/Q acceptance ± 4 % ± 7 %
What kind of research work can be done were RITU separator is not feasible Probing the N Z line up to 112 Ba - decay spectroscopy (proton and α-particle decay) at the 100 Sn region - rp-process - proton-neutron pairing interaction - mirror nuclei o study of isospin symmetry breaking o proton skins (N < Z nuclei) D. Joss - superdeformation and hyperdeformation (N Z 40) Methods - focal plane detector system: o DSSSD, position sensitive gas counter (1 mm granularity) - Tracking o Ge-detectors -MWPC & IC o Z- identification - tape system - focal plane spectroscopy - α, proton, β, γ, β-delayed protons and alphas - prompt and delayed coincidences - in-beam spectroscopy tagging with using focal plane measurables
Phase space correction
Mass separation at focal plane
X-deviations versus TOF can be seen in phase space corrected data -> time correction can be made to improve x-resolution
Simulation of electric field in deflector (code Poisson Superfish) - gap 14 cm - rounded edges - splitted anode - maximum voltage between plates is about 0.5 MV
Simulating particle trajectories in deflector field Simple modified Euler equation is used to trace particles in electric field. Real transfer matrix coefficients can be obtained from these simulations. This more realistic matrix can be used in optical simulations of the new separator. 147 Tm: 222 MeV, 147 u, 37 e 100 MeV, 100 u, 26 e 92 Mo: 362 MeV, 92 u, 32 e 200 MeV, 50 u, 21 e
JIono ionoptical simulations, Jan Sarén Features (some are not implemented yet): both graphical and text interfaces uses GICO/GIOS transfer matrices adjustable aperture slits export/import data real particle parameters as input data (m, E, q) Multiple types of plots Windows and Linux