the light ion guide cb- ecris project at texas a&m university

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


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


The RF-only hexapoleThe RF-only hexapole

SIMION calculations ~ 80% efficiency for 250 cm long sextupole


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


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


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


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


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?


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


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!


the light ion guide cb- ecris project at texas a&m university

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