ecr ion source operations
TRANSCRIPT
Outline
1. 88-Inch Facility Layout
2. Intro to ECRs
3. Cocktail Beams
4. Availability & Reliability
5. Resources to Support Chip Testing and SHE
AECR-U aluminum
plasma chamber
Cyclotron Facility Layout
Janilee Benitez Operations Review March 4, 2020
Cyclotron
The 88-Inch Cyclotron is fed by three ECR ion sources: ECR, AECR-U, and VENUS.
Cave 4A Light
Ion Facility
Cave 4B Heavy Ion
Facility
ECRVENUS
AECR-U
3
Cave 1 BGS
ECR Ion Source Physics
wave
e
ECR
m
Be−
=⋅
µω
Sextupole Magnets
(radial confinement field)
Solenoid Magnets
(axial confinement field)
µ-waves
gas
Ion
beam
3
1
2a
2b4
High Voltage
5
1
+
3
+
2a
2b
4
gas
µ-waves
radial field
= +
+
axial field
5
High Voltage
Ion beam
Key Ingredientse-
TBECR
1=GHzwave
28=−µ
ω
ECR: Electron Cyclotron Resonance
Janilee Benitez Operations Review March 4, 2020 4
Janilee Benitez Operations Review March 4, 2020
ECR’s at the 88-Inch
ECR
1983
Max B-Field: 0.4T
Frequencies: 6.4GHz
Max Power: 0.6kW
AECR-U
1996
Max B-Field: 1.7T
Frequencies: 10, 14GHz
Max Power: 2.6kW
VENUS
2004, 2008 for operations
Max B-Field: 4.0T
(superconducting)
Frequencies: 18, 28GHz
Max Power: 12kW
2
RFen ω∝
5
Janilee Benitez Operations Review March 4, 2020
ECR’s at the 88-Inch
ECR
1983
Max B-Field: 0.4T
Frequencies: 6.4GHz
Max Power: 0.6kW
AECR-U
1996
Max B-Field: 1.7T
Frequencies: 10, 14GHz
Max Power: 2.6kW
VENUS
2004, 2008 for operations
Max B-Field: 4.0T
(superconducting)
Frequencies: 18, 28GHz
Max Power: 12kW
6
MARS
(Dan’s Talk)
(Dan’s Talk)
Beams Produced/Accelerated
Gas,
Gaseous
compoundsLow
Temperature
Oven <800°C
High
Temperature
Oven
<2200°C
Tested in Ion
Source/Not
Accelerated
Sputter
Probe
MIVOC: Metal Ions from
Volatile Compounds
C2B10H12
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With the right tool we can
produce any beam.
Janilee Benitez Operations Review March 4, 2020
VENUS produces 124Xe43+ for users!
Figure: Carlson T A, Nestor N and Wasserman N 1970 Ornl Report 4562
Require hot electrons to reach high
charge states
σ for producing high charge state is
orders of magnitude lower
VENUS produces 124Xe43+ for users!
For Z=54, to reach a Xe+43 charge state
requires ~5x103eV electrons!
What Makes a Good ECR Source?
8
Cocktails and Chip Testing Super Heavy Elements
Stable beam productionGood source conditions
Long term beam productionGood oven technology
Low consumption of metals
High intensity beamsdensity ∝ heating freqency2
2
RFen ω∝
For both, a good ECR must be followed by a good
accelerator!
Janilee Benitez Operations Review March 4, 2020
VENUS ECR Ion Source
1
10
100
1000
104
4 6 8 10 12 14 16 18
Extr
acte
d b
eam
fro
m t
he
Cyclo
tro
n [
en
A]
MeV/nuc
Xe28+
Xe42+
Xe43+
Xe34+
Xe28+
VENUS
AECR
Beams not available with the AECR
Xe44+
Xe42+
Xe34+
• Currently one of the most powerful ECR ion sources in the world
• Exploring limits of ECR ion sources through R&D
x100!
Beams not available
from AECR
16AMeV
Xe47+
20AMeV
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Janilee Benitez Operations Review March 4, 2020
Cocktail Beams Development
20MeV/u M/QProduction
Method
LET
(MeV/(mg/
cm2))
RANGE
(µm)
20Ne8+ 2.50 GAS 1.92 548.5
27Al11+ 2.45 GAS 3.25 463.9
78Kr32+ 2.44 GAS 20.9 243.3
89Y36+ 2.47 Sputter Probe 24.2 244.9
109Ag44+ 2.48 Sputter Probe 33.3 226.8
124Xe47+ 2.64 GAS 45.4 193.8
Development of new cocktail ions using VENUS to increase LET and range underway124Xe43+ in 16MeV cocktail: extends LET from 25 to 50MeV/(mg/cm2) now regularly used197Au52+ in 10MeV cocktail: extends LET from 59 to 86MeV/(mg/cm2) now regularly used
124Xe47+ in 20MeV cocktail: also now regularly used!
CNe
AlAr
CuKr Y Ag
Xe
NO
NeSi
ArClV
Cu KrXe
BO
NeSi Ar
V Cu KrY AgXeBi
Au
BN
Ne Si Ar V Cu KrYAgXeTbTaBi
10
100
1000
0.1 1 10 100
Ra
ng
e in
Si (
µm
)
LET 0° (MeV/(mg/cm2))
88-Inch Cyclotron Cocktail Ions
20MeV/u
16MeV/u
10MeV/u
4.5MeV/u
10
Why the need for 20MeV/u cocktail?
• increasing beam energy allows for
deeper penetration into parts
• Layers on chips are increasing in
thickness
Development for higher energy beams to use for
testing in air if this is requested…ex: 25MeV/u78Kr34+
Janilee Benitez Operations Review March 4, 2020
ECR Ion Source Reliability & Availability
Reliability Fail time due to ECRs since 2/2/2017 is 13.5 hrs!
However, this doesn’t mean all ions were always available!
AECR-U & VENUS not one-to-one replacements for each other.
273K
4 Cryocoolers
LHe
11
20MeV/u M/QProduction
Method
LET
(MeV/(mg/
cm2))
RANGE
(µm)
20Ne8+ 2.50 GAS 1.92 548.5
27Al11+ 2.45 GAS 3.25 463.9
78Kr32+ 2.44 GAS 20.9 243.3
89Y36+ 2.47 Sputter Probe 24.2 244.9
109Ag44+ 2.48 Sputter Probe 33.3 226.8
124Xe47+ 2.64 GAS 45.4 193.8
Availability VENUS availability for beam delivery increased:
Cryostat Modification Implemented in 2017 and tested
successfully in 2019. Additional heaters reduced cryocooler
maintenance from ~8 weeks to 1 week!
However, beam development time decreased!
Shutdown development time is hampered by LCW outages
No cyclotron available during shutdowns
Janilee Benitez Operations Review March 4, 2020
Increase reliability for SHEFailure & Consequence Solution
VENUS HiT Oven Failure:
unreliable, no spare shaft
Build a spare HiT
Oven shaft
VENUS Failure:
Low temperature oven run
at AECR with liner, lower
intensity and higher
consumption
Backup to
VENUS: 3rd/4th
generation ion
source
Mitigating Risks
Increase reliability for cocktailsFailure & Consequence Solution
AECR Failure:
No sputter probe metals (Ag,
Y, Ta, Cu, Tb, Si, V)
Sputter probe with
multiple metals at
VENUS
VENUS Failure:
No high charge state Au, Xe,
Kr
Backup to VENUS:
3rd/4th generation
ion source
-V
-V
-V
+
+
++
+
plasma
Au
Ag
Cu
Increase reliability for cocktailsFailure & Consequence Solution
AECR Failure:
No sputter probe metals (Ag,
Y, Ta, Cu, Tb, Si, V)
Sputter probe with
multiple metals at
VENUS
VENUS Failure:
No high charge state Au, Xe,
Kr
Backup to VENUS:
3rd/4th generation
ion source
VENUS high intensity runs:
Difficult to run high charge
state cocktails after
Backup to VENUS:
3rd/4th generation
ion source
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Janilee Benitez Operations Review March 4, 2020
VENUS’ IntegrationFiscal Year 2007 Fiscal Year 2011
AECR
56.7%
ECR
34.5%
VENUS
8.9%ECR
41.8%
VENUS
1.1%
AECR
57%
ECR
8.9%
VENUS
17.5%
AECR
73.6%
Fiscal Year 2012 Fiscal Year 2016
AECR
60.2%
VENUS
39.8%
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Trend is increased need
for VENUS beams
Source Use
• To fulfill the needs of the chip testing and research communities,
development of VENUS continues
• With the regular use of VENUS for beam production we have less
time for R&D
• R&D is not only needed to develop 4th generation ECRs but also to
develop beams for chip testing and intense beams
Conclusions
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