Transcript The new JYFL separator - INFN-LNL

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 QvDQhQv
-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 25o
- Total length 4.8 m
+ 175Lu —>
211Ac + 4n
Efr = 33 MeV
qave = 6.9
vert. acc. ± 26 mrad
horiz. acc. ± 77 mrad
Acceptance 8 msr
40Ar
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.,
112Sn(86Kr,
3n)195Rn @ 365 MeV
0, ± 26 mrad, 0, ± 1mm
Dispersion 15 mm/%Bρ
if Bρ difference 4 % between
195Rn and beam 86Kr, and
± 7 mrad for beam and ± 26 mrad for 195Rn
RITU QDQQ with 25o dipole magnet
DQQ with 50o dipole magnet
DQQ with 50o dipole magnet, and Bn = -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:
B 
mv
2Tm

q
q
Electric rigidity:
E 
pv 2T

q
q
Resolving power:
R
x |  
2 x00  x | x 
Deflection angles in electric field:
 ER AER qER

p
Ap q 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 109-1015 can be expected
Mass separators all around the world: some trends
DRS:
CARP:
CAMEL:
HIRA:
JAERI-RMS:
FMA:
EMMA:
JYFL new:
Q
S
H
M
O
WF
ED
MD
Q1-Q2-Q3-WF1-WF2-Q4-Q5Q6-S1-S2-MD1-Q7-Q8-Q9
Q1-MD1-H1-H2-ED1-H3-Q2
Q1-Q2-ED1-S1-MD1-S2-ED2
Q1-Q2-ED1-M1-MD1-ED2-Q3-Q4
Q1-Q2-ED1-MD1-ED2-Q3-Q4-O1
Q1-Q2-ED1-MD1-ED2-Q3-Q4
Q1-Q2-ED1-MD1-ED2-Q3-Q4
Q1-Q2-Q3-ED1-MD1
quadrupole
sextupole
hexapole
multipole
octupole
velocity filter
electric dipole
magnetic dipole
(13.0 m)
(8.6 m)
(9.4 m)
(8.2 m)
(9.04 m)
(6.74 m)
Design principles and aberrations
- Maximizing angular, mass and
energy acceptance while minimizing
geometric and chromatic aberrations.
- The largest aberrations are (x|δ2),
(x|θδ) and (x|θ2). These are
minimized by adding a curvature to
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
- Configuration
- Horizontal magnification
- Vertical magnification
- M/Q dispersion
- First order resolving power,
2 mm beam spot
-Solid angle acceptance
- Energy acceptance for
central mass and angle
- M/Q acceptance
FMA
JYFL new
QQEDMDEDQQ
-1.93
0.98
-10.0 mm/%
259
QQQEDMD
-1.58
-4.48
8.1 mm/%
256
8 msr
10 msr
+20 % - 15 %
4%
+20 % - 15 %
7%
What kind of research work can be done were RITU separator is not feasible
Probing the N  Z line up to 112Ba
- decay spectroscopy (proton and -particle decay) at the 100Sn 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
- , proton, , , -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.
147Tm:
222 MeV, 147 u, 37 e
92Mo:
362 MeV, 92 u, 32 e
100 MeV, 100 u, 26 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