The Light Ion Guide CB-ECRIS Project at Texas A&MUniversity Cyclotron Institute
The Light Ion Guide CB-ECRIS Project at Texas A&MUniversity Cyclotron Institute
G. Tabacaru (TAMU), J. Arje (Jyvaskyla), D.P. May (TAMU)G. Tabacaru (TAMU), J. Arje (Jyvaskyla), D.P. May (TAMU)
Project overviewProject overview
Cyclotron Institute Texas A&M:• 88” Cyclotron (decommissioned1986)• K500 Superconducting Cyclotron
Upgrade started 2004 → full speed 2005
Re-activation of 88” Cyclotron – deliverhigh intensity light particle and heavy ionbeams.
Production of rare isotopes for accelerationin K500 Superconducting Cyclotron andhigher intensity stripping and fragmentationbeams.
G. Tabacaru, ECRIS 08, Chicago
Scientific programScientific program
1. Nuclear Astrophysics:a. Radioactive beams from K500: Asymptotic Normalization
Coefficients methodb. Stable beams from 88”: (3He,d) reactions and MDM
spectrometer2. Nuclear Structure:
a. Giant Monopole Resonance and Compressibility: GMR asa nuclear structure effect and compressibility in nucleiwith much higher asymmetry
b. Cluster Structure: radioactive beams and thick targetinverse kinematics technique
3. Fundamental Interactions: superallowed β-decaymeasurements
4. Nuclear Dynamics and Nuclear Thermodynamics
RF-only hexapole
Target ChamberHe ~ 300 – 500 mbar
~ 1mbar
~10-2mbar
~10-6mbar
Faraday Cup
Glaser lens
The Light Ion GuideThe Light Ion Guide
to CBECR
In collaboration with Dr. J. Arje - Jyvaskyla
proton beam
G. Tabacaru, ECRIS 08, Chicago
4×10526110In (4.9h)
2×10528108In (58.0m)
4×10528106In (6.20m)
2×1053592Tc (4.25m)
2×1054564Ga (2.63m)
4×1044554Co (0.19s)
1×1054550Mn (0.28s)
4×1045727Si (4.16s)
particles/sMeV/AProduct (T1/2)
IntensityMax Energy(p,n)
Projected beam intensities from LIGafter K500
Projected beam intensities from LIGafter K500
G. Tabacaru, ECRIS 08, Chicago
The RF-only hexapoleThe RF-only hexapole
SIMION calculations ~ 80% efficiency for 250 cm long sextupole
G. Tabacaru, ECRIS 08, Chicago
Details – Light Ion GuideDetails – Light Ion Guide
Parameters: exit hole diameter (1 mm and 2 mm), pressure, DC-fields,distance between the exit hole and the sextupole, etc …
Pumping system (Pfeiffer):• ROOTS blower 1: 2000 m3/h (+ 6000 m3/h – online condition)• ROOTS blower 2: 1000 m3/h• Turbo pumps: 520 l/s + 2× 520 l/s (CB-ECRIS)
Initial developments:• spark chamber (ionization of impurities, He) → current• 228Th open source (daughters) → alpha particles from 216Po
G. Tabacaru, ECRIS 08, Chicago
Details – CB-ECRISDetails – CB-ECRIS
Design and built by Scientific Solutionsof San Diego, California Operate at 14.5 GHz Two large coils: max ~ 1T Hexapole Nd-Fe-B: ~1.1T
hexapole
axial coil
Electrodesforinjection
WORK IN PROGRESS !!!0
0.5
1.0
1.5
2.0
-15 -10 -5 0 5 10 15
AMPERESData
Axial Displacement(inches)
Mag
netic
Fie
ld(k
Gau
ss)
Charge-Breeder Solenoid QAFinal Magnet Configuration @50 Amps
5-JAN-07
-20
-10
0
10
20
0 90 180 270 360
y = a*sin(b*x+c) max dev:2.1903, r2=0.99384a=11.533, b=3.0093, c=-0.67063
Rotation Angle
Rad
ialM
agne
ticF
ield
(kG
auss
)
TAMU SextupoleInitial QA Checkout
5-JAN-07
G. Tabacaru, ECRIS 08, Chicago
Tests – spark chamberTests – spark chamber
Ifc, Isp vs Ptc
0
2
4
6
8
10
12
14
0 100 200 300 400 500
Ptc [mbar]
Ifc
[nA
]
Ifc [nA]Isp [x0.33mA]
LIG-SP100cm9-Oct-07
Øe = 1.0mmXes ≈ 3.5mmØelectrode =4mmXrods ≈ 29mmIsp = (1.07-1.23)*3.3mAf = 3.485MHzVrf = 6.0V (gen.)Velectrode=floatingVtc = Vrf,dc togetherVsp = 227 VI-Glazer = 0
Ifc vs. +Vfc vs. Ve
0
5
10
15
20
25
30
0 50 100 150 200Vfc [V]
Ifc
[nA
]
Ifc [nA], Ve=+202VIfc [nA], Ve floatsSIMION normalized
LIG27-Jun-07Øe =2.0mmØelectrode =4mmXes ˜ 3.5mmIsp =0.15*3.3mAVsp =238VIfc =ave/100samplesf =5.630MHzVrf =10.0V (gen.)Vtc =-Vrf,dc =8.5VPtc =170mbar
SSmesh 0.8x0.8mm2inside sp-chamber
-->no effect
G. Tabacaru, ECRIS 08, Chicago
Plasma chamber
Microwave 14.5 GHz
Sextupole
Tests – 228Th open sourceTests – 228Th open source
Si det
Aluminized mylar 1.5 µmAluminized mylar 1.5 µm
Ra, Rn, Po
G. Tabacaru, ECRIS 08, Chicago
Tests – 228Th open sourceTests – 228Th open source
• Partially simulate the online conditions• Lower final velocity at the injection in the CB-ECRIS• Alpha particle detection necessary – difficult to fine tune
228Th and daughters alpha spectra
228Th
216Po
212Po
216Po approx 100 α/sec216Po approx 100 α/sec
backgroundbackground
Velocity of the ionsVelocity of the ions
0
5
10
15
20
25
30
35
40
45
50
-40 -20 0 20 40 60 80
Retarding bias [V]
Yie
ld[a
lph
as/s
ec]
approx 20-25 eV
Q: Is this velocity appropriate for an efficient injection in the CB-ECRIS?Q: Is this velocity appropriate for an efficient injection in the CB-ECRIS?
G. Tabacaru, ECRIS 08, Chicago
Future plansFuture plans
CB-ECRIS to be turned on in the next weeks TWT – max 400 W coils at 250 A plasma?!
Inject Ra, Rn, Po Detect alphas at the extraction
IF success GOTO Improve_EfficiencyELSE
Find Stable Conditions for CB-ECRIS
Measure the overall efficiency of the device
CB-ECRIS to be turned on in the next weeks TWT – max 400 W coils at 250 A plasma?!
Inject Ra, Rn, Po Detect alphas at the extraction
IF success GOTO Improve_EfficiencyELSE
Find Stable Conditions for CB-ECRIS
Measure the overall efficiency of the device
G. Tabacaru, ECRIS 08, Chicago
Upgrade TeamUpgrade TeamDr. R.E. Tribble - director
Dr. H. Clark – Project Manager
F. Abegglen – Operation ChiefH. Peeler – Research
Instrumentation
K150 – Re-commission Light Ion Guide &Heavy Ion Guide
Managers
Dr. G. TabacaruDr. G. ChubaryanDr. G. Souliotis
CBECR &New beam lines
Dr. D. MayDr. G. Kim
Radiation issues &Beam dump
Dr. G. TabacaruThank you!
G. Tabacaru, ECRIS 08, Chicago