60 years of Ion
Pumps from
invention to the
latest development.
Alessandro Abatecola
Ion Pump Marketing Manager
Agilent Technologies Vacuum
Product Division
Une immersion dans le monde de l’Ultra Haut Vide : 60 années de pompes ioniques, de ses origines à ses dernières innovations.
Présentateur : Alessandro Abatecola
Depuis la fin des années 50, lorsque la pompe ionique fut inventée chez Varian (maintenant Agilent Technologies), de nombreuses
évolutions techniques ont vu le jour.
Agilent Technologies fut à l’origine de toutes les innovations majeures apparues sur le marché : de la première pompe ionique Diode
à la pompe ionique Triode, puis StarCell; de la gamme de pompes ioniques VacIon Plus à l’unité de contrôle 4UHV pouvant alimenter
jusqu’à 4 pompes ioniques indépendamment et assurer une lecture de la mesure de vide pour chaque pompe, tout en optimisant les
vitesses de pompage grâce à une tension variable.
Bien que les pompes ioniques soient largement et principalement utilisées dans les conditions UHV, la vitesse de pompage maximale
des pompes ioniques se situe aux environs de 10-6 mbar (10-4 Pa). L’intensité de la décharge dans la cellule penning de la pompe
ionique (nombre d’ions qui bombardent la cathode par unité de temps) est fonction de la pression, et est le principal paramètre de la
vitesse de pompage.
Une nouvelle pompe ionique de 200 l/s spécifiquement conçue pour opérer en UHV incorpore ces découvertes pour obtenir une
vitesse de pompage maximale vers 10-8 mbar (10-6 Pa). Nous vous décrirons comment les différents composants de cette pompe
sont traités thermiquement avant assemblage afin d’obtenir le vide limite le plus bas du marché.
Après plus de 60 ans, la pompe ionique reste une pompe inégalable pour l’Ultra Haut Vide, et Agilent reste à la pointe de
l’innovation.
60 years of Varian/Agilent Ion pumps
...AFTER INVENTION OF KLYSTRON BY RUSSEL VARIAN.....
•
1948: VARIAN BROTHERS CO-FOUNDED VARIAN ASSOCIATES
Original activities were focused on MICROWAVE ELECTRON TUBES
Ion pump was invented as the solution for clean pumping of electron tubes
•
1957: INVENTION OF SIP BY R. JEPSEN, L. HALL, J. HELMER
From a single cell to a multi-cell anode
•
1959: VACUUM DIVISION OF VARIAN
Production of Ion pumps starts - VacIon® Pumps
•
1960 – INVENTION OF TRIODE PUMP
Then commercialized by Varian in late 1960 under name “Noble Ion pump” (changed into Triode Ion pump in early 1979)
•
1967- Ion pump manufacturing site in Torino -Italy
In the same years the first installation of large SIP was at CERN in Geneva from 1971 – 1984
•
INTEGRATION OF TSP and NEG CARTRIDGE WITHIN SIP BODY
Used since early history to improve UHV performance of SIP
Equipped with cooling and shields
•
TURBOMOLECULAR PUMPS OVERCOME HV OPERATION OF SIP
Complimentary of SIP toward the higher pressure
All the attempts to improve high pressure operation were stopped and obsoleted by the introduction of TMPs
SIP starts below 10-6 mbar this create a «clean» alternative for high pressure
•
STARCELL SIP (1983): RE-DESIGN OF TRIODE ELEMENT
After two decades of experience – same triode electrode and anode configuration but developing a new cathode structure
 Extended life time, hydrogen pumping, Ar stability
•
HOMOGENEITY OF MAGNETIC FIELD (I.B)
All cell operative at low pressure
Additional secondary manget with Axial-simmetric design
Enhanced homogenity
 Higher pumping speed (especially at low pressure) / no increased in the overall dimension
•
OPTIMIZED VOLTAGE AT EACH PRESSURE RANGE (Multivac/DUAL C.U. (1990) Through the «STEP» option
Benefit:
Change the voltage according to pressure (read throguht Ion current)
Optimized pumping speed in the whole pressure range
 Reduced leakage current
• SEM SPUTTER ION PUMP (2002)
Desinged for E-GUN OF scanning electron microscopes
Less dendride (wiskers) formation, less field emission
 less leakage current spike
 Reliable pressure reading
•
A NEW ERA IN THE CONTROLLER UNIT: 4UHV introduction (2009)
Up to 4 pumps driven simultaneously and indipendently
Any type of element (SC-DI-ND) and mixed combination
Variable voltage (STEP mode) ensures optimum pumping speed and pressure reading
Different Power
•
STANDARD PUMP FOR PARTICLE ACCELERATOR:
ESRF (FR)- SOLEIL (FR) – PSI (CH)- DESY (DE) – POSTECH (KR) – FERMILAB (US)Special customized pumps: -DESY-XFEL (DE)- LIGO-(2500l/s)- NSRRC (100l/s - TW)
Ie. DESY: Together with DESY, Agilent Technologies developed an
inline vacuum pump that can be directly mounted into
a beamline, improving effective pumping speed and
Shielding.
What else can be still invented?
Have you ever seen a pump with maximum pumping speed at low
pressure ?
What new features can be still introduced?
Ion Pump design for improved speed at low
pressure
Scope of the work:
 Ion pumps are normally used at low pressure , 10-8 mbar ( 10-6 Pa ) and below.
 Existing ion pumps have maximum pumping speed in the 10-6 mbar (10-4 Pa ) range.
 Analyze influence of design parameters on pumping speed of an ion pump.
 Experimental test of elements with different parameteres in different operating conditions.
Goal is to optimize these parameters to improve the overall pumping speed
and improve it at lower pressures
Ion Pumps main pumping principle (for getterable gases)
 Penning Cell , crossed B and V act as an electron trap
 Electrons ionizes gas molecules through collisions
 Ions are created in order to bombard the Titanium cathode
 Even if some ions diffuse into the cathode, this is not the main pumping effect
 Sputtering of chemically active Titanium film on the anode
 Neutral Gas molecules stick to the Titanium film (chemisorption) and are buried in the anode
 This is the main pumping effect and the only stable one
We can summarize that:
Ion pumps do not pump ions by diffusion into the cathode , but pump neutral molecules by
chemisorption by the sputtered cathode material on the anode
Discharge intensity in Low Magnetic Field and High
Magnetic Field modes
Low pressure
High pressure
20 mm dia cell
7.63  Va
Btransition 
raP 0.05
P (mbar)
1,00E-06
1,00E-07
1,00E-08
1,00E-09
@ 7 kV @ 5 kV @ 3 kV
1256
1061
823
1409
1191
922
1580
1336
1035
1774
1499
1161
I/P measurements - Experimental set up
1
Electromagnet poles
3
Vacuum chamber: UHV gauge,
variable leak valve, independent ion
pump
2 “special” ion pump body with HV
feedthrough
4 Ion Pump element to be tested
5 Rough Valve
Pump Parameter Design
Optimum Magnetic Field for I/P 1400 / 1600 Gauss
 Present Ion Pumps work with 1100/1200 Gauss, obtainable with commercially available magnets and
conventional design
Optimum cell diameter 20 to 24 mm
Dia , mm
Area , mm2
No of Cells
16
20
24
28
201
314
452
615
75
48
33
24
 Present Ion Pumps have cells from 15 to 25 mm diameter
We have to work on Magnetic Field
Ion Pump Magnetic field
Conventional, 150 l/S
New design, 200 l/s
Ion Pump Magnetic field
Conventional
Red 900 G
Orange 1000 G
Yellow 1250 G
Grey > 1500 G
New design
Pumping speed after saturation, Nitrogen
350
300
250
S (l/s)
200
150
100
7 kV - N2 Diode
50
5 kV - N2 Diode
3 kV - N2 Diode
Unsaturated
0
1,E-11
1,E-10
1,E-09
1,E-08
P (mbar)
1,E-07
1,E-06
1,E-05
Innovative Vacuum Treatment process -XHV
Innovative application of Vacuum Firing* process
Applied to ALL surfaces exposed to vacuum
(before pump’s assembly)
Effectively reduces the Hydrogen outgassing rate (up to
90%)
Boost capability to reach eXtreme High Vacuum (XHV)
levels.
Vacuum
Firing
Process largerly used in the WW research Centers
Applied to VIP200 pump’s family only: first Pump in
the market
Summary
I/P values have been measured for a wide range of Ion Pumps key design
parameters such as V , B , cell dimensions
The influence of B on I/P has been experimentally measured and a value
higher than the one used in existing ion pumps has been proved to be
necessary to improve the performances, especially at lower pressures.
With optimized design parameters it is possible to design an ion pump with
the highest pumping speed per unit volume ( 200 l/s in the same
dimensions of conventional 150 l/s).
Even more important, the maximum pumping speed of 200 l/s is reached
in the 10-8 mbar (10-6 Pa ) range, where a conventional 150 l/s usually
provides 125 l/s
Next step: to extend the same design to different sizes of ion pumps
New Agilent VIP200
eXtreme High Vacuum Performance
The first ion pump with maximum pumping speed at low pressure
Courtesy of CERN