A three‐dimensional rf quadrupole ion trap has been constructed to study ion production by electron‐impact ionization. Gases and atoms in an atomic beam can be investigated. The method can be extended to the study of photon ionization and of the production of multiply charged ions by a single collision and/or by step‐by‐step ionization. Total electron‐impact ionization cross sections of helium have been measured and are σe(350 eV) =0.26(6) ×10−16 cm2 and σe(500 eV) =0.21(4) ×10−16 cm2. Equations are derived to operate the rf ion trap in the symmetric storage mode.

1.
R. E.
Olson
and
A.
Salop
,
Phys. Rev. A
16
,
531
(
1977
).
2.
A.
Salop
,
Phys. Rev. A
14
,
2095
(
1976
).
3.
E. D. Donets and V. I. Ilyushchenko, Proc. of the Joint Institute of Nuclear Research, Dubna, 1974 (unpublished).
4.
P.
Lambropoulos
,
Phys. Rev. A
9
,
1992
(
1974
).
5.
Ch.
Moore
,
Natl. Bur. Stand. Rep. Data Ser.
34
,
1
(
1970
).
6.
K. T.
Dolder
,
Contemp. Phys.
17
,
237
(
1976
).
7.
P. A.
Redhead
and
G. P.
Gopalaram
,
Can. J. Phys.
49
,
585
(
1971
).
8.
J. B.
Hasted
and
G. L.
Awad
,
J. Phys. B
5
,
1719
(
1972
).
9.
H. A. Schuessler, in Progress in Atomic Spectroscopy (Plenum, New York, 1979), p. 999.
10.
H. A.
Schuessler
,
E. N.
Fortson
, and
H. G.
Dehmelt
,
Phys. Rev.
187
,
5
(
1969
).
11.
G.
Rettinghaus
,
Z. Angew. Phys.
22
,
321
(
1967
).
12.
R. D.
Rundel
,
D. E.
Nitz
,
K. A.
Smith
,
M. W.
Geis
, and
R. F.
Stebbings
,
Phys. Rev. A
19
,
33
(
1979
).
13.
D.
Rapp
and
P.
Englander‐Golden
,
J. Chem. Phys.
43
,
1464
(
1965
).
14.
P. T.
Smith
,
Phys. Rev.
36
,
1293
(
1930
).
15.
B. L.
Schramm
,
H. R.
Moustafa
,
J.
Schutten
, and
F. J.
de Heer
,
Physica
32
,
734
(
1966
).
16.
Y. K.
Kim
and
M.
Inokuti
,
Phys. Rev. A
3
,
665
(
1971
).
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