Development of a Laser Ions Source for Beam Purification at ......832.380 nm 12013.739 cm-1 57895.10...
Transcript of Development of a Laser Ions Source for Beam Purification at ......832.380 nm 12013.739 cm-1 57895.10...
Y. Liu, C. Baktash, J.R. Beene, J.F. Liang, D.W. Stracener
C.C. Havener, H.F. Krause, D.R. Schultz, C.R. Vane
Physics Division, Oak Ridge National Laboratory
Oak Ridge, Tenneessee
in collaboration with the Larissa Group, Physics Department, Uni-Mainz, Germany
Christopher Geppert, Tina Gottwald, Thomas Kessler*, Ben Tordoff*, Katja Wies, Klaus Wendt
*borrowed from JYFL
Development of a Laser Ions Source for Development of a Laser Ions Source for
Beam Purification at HRIBFBeam Purification at HRIBF
• The Holy Field RIB facility at ORNL
• Off-line ion source test facilities at HRIBF
• Laser ion source developments
– Accessible elements and efficiency
– Atomic spectroscopy on excitation schemes
– Emittance and temporal laser ion pulse profile
– Source material and atomic beam evaporation investigations
• RF quadrupole ion cooler for negative ions
• Isobar suppression by laser photodetachment
���� contact [email protected]
Outline
Recoil Mass Spectrometer
(RMS)
Injector for Radioactive Ion
Species 1 (IRIS1)
25MV Tandem
Electrostatic Accelerator
Daresbury Recoil Separator (DRS)
Oak Ridge Isochronous Cyclotron (ORIC)
On-Line Test
Facility (OLTF)
High Power Target
Laboratory (HPTL)
Stable Ion Injector (ISIS)
EngeSpectrograph
Holyfield Radioactive Ion Beam Facility
� High Power Target Laboratory (HPTL) installed
� Beam development R&D facility for RIA
� High power ORIC beams utilized for development of advanced targets, target/ion
sources, beam preparation components, and purification techniques.
� Injector 2 for Radioactive Ion Species 2 (IRIS2) initiated
� Second fully operational production station with substantially improved functions
� Enlarged space to accommodate new production techniques such as RILIS
� Laser lab. allocated to provide an operating venue for on-line resonance laser ion
sources and other in-beam purification schemes employing lasers.
� Schedule of implementation: January 2006 - February 2009
HRIBF Major Updates 2005 ���� today
HRIBF with HPTL / IRIS2 Status 2007 - 2009
IRIS1
HPTL / IRIS2
Laser Room
Off-line Ion Source Test Facilities 1 & 2
Off-line Ion Source Test Facility 1
ISTF-1 � negative ion beams,
quadrupole cooler and
laser photodetachment
Ion Cooler
Energy Analyzer
X-Y Emittance Device
Off-line Ion Source Test Facility - 2 (ISTF-2)
ISTF-2 � positive ion beams,
source developments -ECR source, laser ion source
HV @ 30 kV
• Collaboration between Atomic Physics Group, ORNL Physics Division
Yuan Liu, Charly C. Havener, Herb F. Krause, Dave R. Schultz, C. Randy Vane
+ support by Cyrus Baktash, Jim R. Beene, J.F. Liang, Dan W. Stracener
and the Larissa Coll., Physics Department, UMz
Christopher Geppert, Thomas Kessler, Katja Wies, Tina Gottwald, Ben Tordoff, K. W.
• Project started at ISTF2 in 2004 using RIA R&D funding
• One joint experimental campaign of ~3 weeks per year conducted
(09/2004, 09/2005, 10/2006, 10/2007,…)
• Primarily : complete Ti:Sapphire laser system provided by Mainz
since 2006 : sequential purchase of ORNL Ti:Sa laser system
• Elements successfully investigated at ORNL so far:
� (2004) Sn, Ni, Ge; (2005) Cu, Mn; (2006) Fe, Al;
ORNL Laser Ion Source Project
Photonics Ti:Sapphire Laser 3 fundamental- full range tunable -
Photonics 100 W Pump Laser
UMz Ti:Sapphire Lasers SS 1 DS 2
Mixed Ti:Sapphire Laser Setup at HRIBF - 2006
UMz Tripler & Quadrupler
Activities at the ISTF 2 Laser Ion Source
• Identification of Ti:Sa laser excitation schemes for various elements
• Optimization of source geometry – transfer tube / atomizer funnel
• Study of source material – Ta, TaC, …
• Optical Spectroscopy on Rydberg and auto-ionizing states
• Investigation of spatial and temporal behaviour of laser ion beam
���� Optimization of laser ionization conditions and efficiency
IP62317.44 cm-1
217.963 nm11469.828 cm-1
(4th Harmonic)
0 cm-1
45879.31 cm-1 3d94s4p 2P0 J=3/2
3d106d 2D J=3/2
761.23 nm13136.71 cm-1
3d94s5p4D0J=3/2
832.380 nm12013.739 cm-1
57895.10 cm-1
832.238 nm12015.789 cm-1
70414.50 cm-13d94s5p4F0J=5/2
798.76 nm12519.40 cm-1
3d106d 2D J=5/2
3d10 2S J=1/2
Typical Excitation Scheme: Copper
Scheme 1Scheme 2
99.7% @2300K
0 5000 10000 15000 20000 25000
0
5
10
15
20
surface ions not corrected
surface ions corrected
ion c
urr
ent
/ nA
time / s
~2.4%
Cu
>3.3%
Ge
2.7%22%
NiSn
0
10
20
30
40
50
60
70
0 1 2 3 4 5 6 7 8 9 10
Time (hour)
Ion
Curr
en
t (n
A)
21%
23%
0
5
10
15
20
25
0 2 4 6 8 10 12
Time (hour)
I (nA)
Sn Ni
Sn: controllable
and reproducible release
Ni: reaction with Ta source
material above Tcritical
Cu
Cu: explosive evaporation
Efficiency and Detection Limit
Importance of geometry and material of atomizer and transfer tube
Pureness of buffer gas in gas-cell or gas-filled RFQ trap
1 2 0 0 0 1 2 0 5 0 1 2 1 0 0 1 2 1 5 0 1 2 2 0 0 1 2 2 5 00
4
8
1 2
1 66 1 3 0 0 6 1 3 5 0 6 1 4 0 0 6 1 4 5 0 6 1 5 0 0 6 1 5 5 0 6 1 6 0 0
ion
cu
rre
nt
/ nA
ν3 / c m
-1
νto ta l
/ c m-1
Atomic Level Spectroscopy
12260 12265 12270 12275 12280 122850
1
2
3
4
5
61575 61580 61585 61590 61595 61600
ion c
urr
ent /
nA
ν3 / cm
-1
νtotal
/ cm-1
Atomic Rydberg levels
17 < n < 72
Nickel
Small δ with increasing trend � assignment of configuration 3d9(2D5/2) nf 2[7/2]o3,4,5 or nf 2[9/2]o3,4,5
Ionization potential: EIP (Ni) = 61 619.8 (1) cm-1,
(EIP(Lit.) = 61 619.1(10) cm-1)
R.H. Page and C.S. Gudeman,
J. Opt. Soc. Am. B 7 (1990) 1761
20 30 40 50 60 70
-0,10,00,1
12000
12050
12100
12150
12200
12250
61300
61350
61400
61450
61500
61550
61600
Resid
uals
Waven
um
ber
thir
d s
tep /
cm
-1
Principal quantum number n
Tota
l e
nerg
y /
cm
-1
20 30 40 50 60 70
-0,15
-0,10
-0,05
0,00
0,05
0,10
0,15
Quantu
m d
efe
ct
δ
Principal quantum number n
Quantum Defect δδδδ and Ionization Potential
Precision:
~ 1 GHz
≅ 0.05 cm-1
Nickel
0
400
800
1200
1600
2000
0 100 200 300 400 500
Heating Current (A)
Te
mp
era
ture
(C
)
Ionizer cavity
Vapor transport tube
Finite element thermal analysis
� temperature distribution
� drift field profile
Measured Temperatures
Ion Source Geometry and Material Optimization
1
400
554.913
709.826
864.739
1020
1175
1329
1484
1639
1794
NODAL SOLUTION
STEP=4
SUB =15
TIME=4
TEMP (AVG)
RSYS=0
SMN =400
SMX =1794
Calculated temp. profile agrees …
Heating current = 400A
0 40 80 120 160 200 240 280
0.0
0.2
0.4
0.6
0.8
1.0
Sn, Ionizer 300 A / Target 300A
Cu, Ionizer 355A / Target 50A
Ni, Ionizer 400A w/o Target
norm
aliz
ed c
ounts
time / µs
Time Profiles of Different Elements
repeller = 0V
0
0.2
0.4
0.6
0.8
1
-50 0 50 100 150 200 250 300
Time (us)
Co
un
ts (
a.u
.)
Cu data
Sn data
Cu-MC
Sn-MC
Universality of the RIMS approach
Presently laser ion beams of 19 elements available from hot cavity Ti:Sa RILIS or LIST
under preparation: --- Co, Cd, In, Sb, Te, V ---
1H 2He
3Li 4Be 5B 6C 7N 8O 9F 10Ne
11Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar
19K 20Ca 21Sc 22Ti 23V 24Cr 25Mn 26Fe 27Co 28Ni 29Cu 30Zn 31Ga 32Ge 33As 34Se 35Br 36Kr
37Rb 38Sr 39Y 40Zr 41Nb 42Mo 43Tc 44Ru 45Rh 46Pd 47Ag 48Cd 49In 50Sn 51Sb 52Te 53I 54Xe
55Cs 56Ba 57La 72Hf 73Ta 74W 75Re 76Os 77Ir 78Pt 79Au 80Hg 81Tl 82Pb 83Bi 84Po 85At 86Rn
87Fr 88Ra 89Ac 104Rf 105Ha 106 107 108 109 110 111 112 113
58Ce 59Pr 60Nd 61Pm 62Sm 63Eu 64Gd 65Tb 66Dy 67Ho 68Er 69Tm 70Yb 71Lu
90Th 91Pa 92U 93Np 94Pu 95Am 96Cm 97Bk 98Fc 99Es 100Fm 101Md 102No 103Lr
..with fundamental & frequency doubling.
..with frequency tripling.
..with frequency quadrupling.
..successfully tested.
Bk 98Fc 99Es 100Fm 101Md 102No 103Lr
HR-RIMS excitation schemes accessible …..using Ti:Sa lasers
Conclusion & Outlook
• HRIBF laser ion source development
– Ti:Sapphire laser system with 100 W pump laser on its way
– Strong off-line activities at ISTF 2
• source and material optimization
• identification of excitation schemes
– Preparation of on-line activities at HRIBF – IRIS 2
• Positive ion production & charge exchange
& laser photodetachment in cooler/buncher