The researches of kinetic electron emission for creation of new-type current source
It is suggested that the high energy electrons produced in ionization due to the nuclear particle flow should be used for effective conversion the radioactive decay energy into electrical energy. The conversation of secondary electron emission energy enables one to create a power source with a typic...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2000 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2000
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| Цитувати: | The researches of kinetic electron emission for creation of new-type current source / V.M. Balebanov, V.P. Zhurenko, V.I. Karas`, I.V. Karas`, S.I. Kononenko, S.S. Moiseev, V.I. Muratov // Вопросы атомной науки и техники. — 2000. — № 1. — С. 193-196. — Бібліогр.: 6 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860179049909846016 |
|---|---|
| author | Balebanov, V.M. Zhurenko, V.P. Karas, V.I. Karas, I.V. Kononenko, S.I. Moiseev, S.S. Muratov, V.I. |
| author_facet | Balebanov, V.M. Zhurenko, V.P. Karas, V.I. Karas, I.V. Kononenko, S.I. Moiseev, S.S. Muratov, V.I. |
| citation_txt | The researches of kinetic electron emission for creation of new-type current source / V.M. Balebanov, V.P. Zhurenko, V.I. Karas`, I.V. Karas`, S.I. Kononenko, S.S. Moiseev, V.I. Muratov // Вопросы атомной науки и техники. — 2000. — № 1. — С. 193-196. — Бібліогр.: 6 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | It is suggested that the high energy electrons produced in ionization due to the nuclear particle flow should be used for effective conversion the radioactive decay energy into electrical energy. The conversation of secondary electron emission energy enables one to create a power source with a typical voltage of (10-20) V and a capacity above 2000 KWt×h/kg, this being much higher than for common sources. Moreover, the operation of this type of sources does not require heating to high temperature and use of a refrigerator; this significantly extends their area of application. The experimental studies into secondary emission characteristics of various materials were carried out to optimize binary cell materials of a secondary - emission radioisotope current source. The total current as a function of collector materials was measured. New data on the secondary emission characteristics of certain materials were obtained. It was ascertained that the total binary cell current had an effect upon secondary electron - electron emission. By way of example, a typical power dependence of voltage was investigated for copper collector; the optimum voltage value corresponding to peak power was calculated too.
|
| first_indexed | 2025-12-07T18:01:10Z |
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ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ 2000. №1.
Серия: Плазменная электроника и новые методы ускорения (2), с. 193-196.
193
UDK 533.9
THE RESEARCHES OF KINETIC ELECTRON EMISSION FOR
CREATION OF NEW-TYPE CURRENT SOURCE
V.M. Balebanov*, V.P. Zhurenko**, I.V. Karas’***,V.I. Karas’***, S.I. Kononenko**, S.S.
Moiseev*, V.I. Muratov**.
*Institute for Space Research, Russian Academy of Sciences, Moscow, Russia
**V.N.Karazin Kharkov National University, Kharkov, Ukraine
***National Science Center, Kharkov Institute of Phisics and Technology, Kharkov, Ukraine
It is suggested that the high energy electrons produced in ionization due to the nuclear particle flow
should be used for effective conversion the radioactive decay energy into electrical energy. The
conversation of secondary electron emission energy enables one to create a power source with a
typical voltage of (10-20) V and a capacity above 2000 KWt×h/kg, this being much higher than for
common sources. Moreover, the operation of this type of sources does not require heating to high
temperature and use of a refrigerator; this significantly extends their area of application. The
experimental studies into secondary emission characteristics of various materials were carried out to
optimize binary cell materials of a secondary - emission radioisotope current source. The total current
as a function of collector materials was measured. New data on the secondary emission characteristics
of certain materials were obtained. It was ascertained that the total binary cell current had an effect
upon secondary electron - electron emission. By way of example, a typical power dependence of
voltage was investigated for copper collector; the optimum voltage value corresponding to peak power
was calculated too.
1. Steady-state nonequilibrium distributions
At present, the development and wide use of
powerful sources of particles and energy arouse
considerable interest in the nonequilibrium states of
various physical systems. The Fermi-Dirac and
Maxwellian functions are the thermodynamically
equilibrium electron distribution functions in
degenerate or classical plasmas, respectively. These
functions are, correspondingly, the exact solutions of
the quantum or classical Boltzmann collision integral
[1].
The steady-state nonequilibrium distributions
can be found by exactly solving kinetic equations. This
is especially true in regard to the physical systems for
which the interaction of waves or particles can be
described by the kinetic equations for waves, quasi-
particles, and particles. The universal steady-state
nonequilibrium power-law distributions in the form:
( ) sN E A E−= ⋅ ,
(where s is the power index, A is constant) are the exact
solutions of the Boltzmann collision integral. For such
distributions to exist, there must be a source and a sink
of energy that provide a constant energy flux in the
momentum space [2].
These conditions take place when the kinetic
secondary electron emission induced by ions occurs. It
is well known, that passage of fast ions through
substances initiates ionization of medium atoms. As a
result of interaction with ions, some electrons leave
atoms. They may enter the vacuum if their momentum
have a suitable value and direction, i.e. secondary
electron emission induced by ions takes place. In this
case, a steady-state nonequlibrium electron distribution
N(E) with power dependence of electron energy can be
formed because of the presence of a source and sink of
energy and a constant energy flow in momentum space
[2].
The experiments have shown that the energy
distributions of fast ion-induced secondary electron
emission are the power-law function with power indices
differening by various energy intervals [2]. The
generalization of the secondary electron emission theory
for nonequilibrium electron distribution functions
makes it possible to obtain the secondary electron
current as a function of retarding potential U:
I U A E
m s si
i si
i ii k
( ) ( )
( )( )
= ⋅
+ +
×+
=
∑π
2
2 1
1 2
2
3
( ) ( )
( ) ( )
( ) ( )[ ]
×
+ −
⋅ −
−
− + − ⋅ −
× ⋅
× +
+
+
− −
−
+
− +
+
s E
E
i k
s E
E
i k
E q U
E
E q U
E
i k
i
i
i
s
i
i
i
s
e
i
e
i
s
i
i
i
1 1
2 1
1
1
1
2
1 1
0 0 2
Θ
Θ
Θ
( ) , ( )
A E
m
A E
mi
i
si
i
i
si2 2
1
1
=
+
+
,
194
where E0 = EF + ϕ is the minimum energy in the
distribution, Ei is the boundary of the energy interval
within which the distribution is described by a power-
law function with the power index s, m is the electron
mass, Θ(x) is the theta-function, Ai is determined from
the recurrent formula, and k is determined from the
inequality Ek-1 ≤ E0 + qeU< Ek. [2].
The current-voltage characteristic of such
secondary emission source of electrons is sloping
considerably slower than that of the thermoemission
cathode. A portion of fast electrons of the secondary
electron emission is substantially greater than that of the
thermoemission [3].
A coefficient of the secondary electron
emission (SEE) γ is an integral parameter describing
secondary electron emission induced by ions. It is
determined by the formula:
γ = Ne /Ni,
where Ne is a total number of the secondary electrons
that have left a material; Ni is a number of primary ions.
We consider the secondary-emission coefficient
γ to be proportional to the energy loss per atom ( i.e., to
depend on the atom density N as N-1/3) and inversely
proportional to the excitation potential Φ, which takes
into account the collective interaction of a charged
particle with the electron subsystem of the material.
According to [3], the Sternglass formula can be
modified as follows:
y
Z
N
dE
dx
eff
p
= −
−
ς 1
2
1 3Φ /
where (-dE/dx)p is the energy loss by proton whose
velocity is equal to the velocity of the incident ion; Z1eff
is the effective charge of an ion in the target; ζ is a
constant.
The measurements have shown that the γ value
can reach a few tens of emission electrons per one
bombarding α-particle, as, for example, for beryllium.
The presence of a great number of high energy electrons
allows one to transform effectively the energy of the
nuclear α-particle into electrical one [4].
2. The secondary emission radioisotope
source of current
On the basis of the previously obtained results,
we propose a secondary-emission radioisotope current
source (SERICS) [5]. The source consists of a
radioisotope layer 2 placed inside a vacuum container 1
(see Fig. 1). Metallic emitters are arranged on each side
of the layer. The emitter thickness is less than the mean
path of the charged particle emitted by the radioisotope
in the emitter material. Each emitter consists of
alternating layers of two different metals 3 and 4 with
different secondary-emission coefficients. The layers are
electrically isolated by dielectric gaps.
A high efficiency of the radioisotope current
source of this type is determined by the fact that
secondary electrons are produced along the entire path
of charged particle in metal; i.e., the charged particle
energy is directly transformed into electron energy; the
number and average energy of these electrons are much
above those for the thermal electron emission [3].
It has been stated previously that the use of
heavy particles in electric-current sources results in a
high efficiency of secondary electron production due to
a negligibly small scattering of these particles (i.e., they
move along almost straight trajectories). The secondary-
electron distribution function is nonequilibrium; the
average energy of the emitted secondary electrons
exceeds 10 eV. The source efficiency increases as a
result of an increase in the secondary emission under the
action of δ-electrons . As a result, this current source has
high energetic parameters proportional to the number of
the emitter layers.
3
_
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������������������������������������������������������
������������������������������������������������������
������������������������������������������������������
������������������������������������������������������
������������������������������������������������������
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������������������������������������������������������
+
4
2
1
Fig. 1. Schematic diagram of the secondary
emission radioisotope source of current: 1-
vacuum container, 2- radioisotope layer, 3 and 4-
layers of two different metals with different
secondary-emission coefficients
Since the total thickness of the emitter does not
exceed the mean path of the charged particle emitted by
a radioisotope, the number of layers and, consequently,
the emitter efficiency can be increased only by making
each layer thinner.
However, as the layer thickness decreases, the
construction loses its rigidity. This can break the electric
insulation between layers. For example, if the layers are
bent, the vacuum gaps between them become narrower.
Earlier we have also proposed a secondary
emission current source with thinner emitter layers and,
at the same time, with a sufficiently high rigidity of the
emitter [5].
This problem was solved by developing a
SERICS, where the radioisotope and the emitter with a
thickness less than the mean path of the charged particle
emitted by the radioisotope were placed inside the
vacuum-tight case. The emitter consists of alternating
electrically insulated layers made of two different
materials with different coefficients of secondary
electron emission. The dielectric grids, located between
the emitter layers, serve to insulate the layers electrically
from each other and to improve the rigidity of the
emitter construction. The thickness of the dielectric grid
is larger than the thickness of the emitter layers. To
195
attain a better effect, the dielectric grid must be
deposited directly on one of the emitter layer. One of the
versions uses the ceramic grid, and the other one uses
the plastic grid [5].
By using all the technical solutions presented
above, one can create a secondary emission radioisotope
source of the current with a substantially better energetic
parameters, of smaller mass and sizes .
The basic element of SERICS is a binary cell
consisting of two thin layers made from different
materials. The difference of secondary emission
coefficients of these materials (γ1 - γ2 ) is the principal
characteristic which determines efficiency of this device.
This paper presents the researches of the electrophysical
parameters of the binary cell.
3. The experimental setup
The experiments were carried out with the
device, schematic diagram of which is shown in Fig. 2.
Fig. 2. Schematic diagram of the experimental
setup: 1- vacuum chamber, 2- radioisotope
source of α-particles, 3- beryllium foil, 4-
moveable damper, 5- massive expendable
collector, 6- high vacuum valve, 7- electrometric
voltmeter, 8- power supply, 9- magnetic
discharge pump
The prototype of the binary cell consisting of
radioisotope source of α-particles with Pu239 isotope 2,
the emitter of a beryllium foil 3 and the massive
expendable collector 5 were placed in a vacuum
cylinder chamber 1. The radioisotope source 2 produced
an α-particle beam with intensity of 4,64⋅106
particles/sec and an energy of 5,15 Mev. The beryllium
foil thickness of 20 µm was chosen to be less than a
mean path of α-particle with given energy in this
material. The α-particles beam, passing through the
emitter 3, induced the secondary electron emission from
the outer emitter surface and from the surface of the
massive collector 5. The collector current were
measured by an electrometric voltmeter 7 with input
impedance of 1016 Om. Voltage of different polarities
was applied to the emitter-collector gap and was
changed from 1 to 300V. For adjusting the system, a
moveable damper 4, shutting the flows of α-particles
and emitted electrons, was placed between the emitter
and the collector. The residual gas pressure in the
vacuum chamber was less than 10-4 Pa. The chamber
was pumped out with a magnetic discharge pump 9 and
mechanical forevacuum pump with a nitrogen-cooled
trap. The plates made from copper, silver and a set of
Faraday cups, consist of 33 copper tubes 10 mm in
diameter and 100 mm in length, were used as collectors.
4. The experimental results and discussion
The collector current as a function of voltage
applied to the emitter-collector gap for the copper
collector and the set of Faraday cups is shown in Fig. 3.
-40 -20 0 20 40 60 80 100
-3
-2
-1
0
1
2
3
2
1I, pA
U, V
a
-4 -2 0 2 4
-1
0
1
2
3
2
U , V
I, p A
b
Fig. 3. The experimental current-voltage
characteristics for the different collectors: 1- set of
Faraday cups, 2- copper collector
It is obvious from Fig.3a that the curve of
current-voltage characteristics (CVC) for the set of
Faraday cups does not steeply slope up and has no
maximum in comparison with one for copper collector.
The presence of high energy tail in the secondary
electron distribution causes the secondary electron-
electron emission (SEEE) of the binary cell materials.
Slow SEEE electrons make essential contribution to the
total current. This is obvious from the comparison of
experimental current-voltage characteristics (CVC) for
different collectors. For designing SERICS it is
necessary to select the materials, taking into account not
only the coefficient γ but also the coefficient of SEEE σ
so that a value of electron yield difference ξ=(γ1 +σ1)-
(γ2 +σ2 ) must be maximum.
The device under review is a current source.
That is why, it is very important to know optimum
196
source power which develops across the load. It has
been shown earlier that the energy distributions of
electrons of the secondary electron emission induced by
fast ions are the power-law functions with different
power indices for different energy ranges. Therefore, it
is possible to use generalized formula of secondary
electron emission theory of nonequilibrium electron
distributions to the current of secondary electrons as a
function of the retarding potential (1). The
nonequilibrium electron distribution for copper sample
has the limits of energy range E1=30 eV and E2=200 ,
within which the distribution is described by the power-
law function with the power indices of s1=-4 and s2=-
2.25, respectively [6]. In this case, it is possible to
obtain the typical power dependence on voltage. Using
the formula (1), we have calculated dependence of
source power, which develops across the load, on
voltage (Fig. 4).
0 10 20 30 40 50 60 70 80
0
2
4
6
8
10
12
14
16
Po
we
r,
[p
er-
un
it]
Voltage, [V]
Fig. 4. Theoretical dependence of source
power, which develops across the load, on voltage
The optimum value of voltage corresponding
to the power maximum, is equal 37 V. This means that
the optimum operation of current source will be in case
load resistance, which determines output voltage of
source, is chosen adequatelly. However, some
discrepancy has been found between experimental CVC
and theoretical dependence defined by the formula (1)
in low energy range [3]. The slow electrons make an
essential contribution to the total binary cell current.
Formula (1) does not satisfy the binary cell conditions,
because, firstly, it does not take account of presence of
the second plate; secondly, it does not allow for the
secondary electron-electron emission.
In addition, we carried out an experimental
study of the dependence of the binary cell power on
voltage. For the purpose, the emitter was connected to
earth and the load resistance was placed into a collector
circuit. In these experiments we measured voltage drop
across the load resistor, which value was changed from
56 GOm to 5000 GOm. The plate made from silver was
used as the collector. The measured experimental
dependence of power on voltage is shown in Fig. 5.
It is obvious that the power which develops
across the load has maximum at U=0.67V. The working
point lies in narrow voltage range of the current-voltage
characteristic for the real binary cell. The maximum
working voltage can not be higher than one for point
where the total current becomes zero (see Fig.3b). In
order to step up this maximum voltage, it is essential to
increase the value of ξ..
0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4
0,1
0,2
0,3
0,4
0,5
0,6
Po
w
er
, [
pW
]
Voltage, [V]
Fig.5. Experimental power dependence on voltage
5. Conclusion
In this paper the investigation of the binary cell
electrophysical parameters of the SERICS have been
carried out. It was shown that the secondary electron-
electron emission from both plates of the binary cell
takes great effect on power, which develops across the
load. In order to increase this power and to approach the
optimum value of voltage to the theoretically calculated
one it is necessary to select materials, taking account of
both coefficient γ and σ.
6.References
1. V.P. Silin. Vvedenie v Kineticheskuyu Teoriyu
Gazov // Moscow: Nauka, 1971.
2. E.N. Batrakin, I.I. Zalyubovskii, V.I. Karas' et al.
Issledovanie vtorichnoi electronnoi emissii iz tonkih
plenok Al,Cu,Be, induzirovannoi puchkom protonov 1
MeV // Zh. Eksp. Teor. Fiz.,, 1985, vol. 89, p. 1098.
3. . E.N. Batrakin, I.I. Zalyubovskii, V.I. Karas' et al.
Eksperimentalnie issledovaniya vtorichnoi electronnoi
emissii iz tonkih plenok, induzirovannoi α-chasticami //
Poverkhnost', 1986, no 12, p. 82.
4. V.I. Karas', S.S. Moiseev. O preobrazovanii yadernoy
energii v electricheskuu na osnove neravnovesnih
raspredeleniy // Ukr.Phis.Zhurn., 1979, vol.24, N.11, p.
1724-1728.
5. V.M. Balebanov, S.S. Moiseev, V.I. Karas' et al.
Vtorichno-emissionniy radiizotopniy istochnik toka //
Atomnaya energiya, 1998, vol.84, p.398.
6. Batrakin E.N., Kononenko S.I., Muratov V.I., Ob
eksperimentalnom issledovanii vtorichnoi electronnoi
emissii, induzirovannoi α-chasticami iz mednoy plenki
// Ukr.Phis.Zhurn., 1985, V.30, N.8, P. 1185-1186.
|
| id | nasplib_isofts_kiev_ua-123456789-81667 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T18:01:10Z |
| publishDate | 2000 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Balebanov, V.M. Zhurenko, V.P. Karas, V.I. Karas, I.V. Kononenko, S.I. Moiseev, S.S. Muratov, V.I. 2015-05-19T08:36:08Z 2015-05-19T08:36:08Z 2000 The researches of kinetic electron emission for creation of new-type current source / V.M. Balebanov, V.P. Zhurenko, V.I. Karas`, I.V. Karas`, S.I. Kononenko, S.S. Moiseev, V.I. Muratov // Вопросы атомной науки и техники. — 2000. — № 1. — С. 193-196. — Бібліогр.: 6 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/81667 533.9 It is suggested that the high energy electrons produced in ionization due to the nuclear particle flow should be used for effective conversion the radioactive decay energy into electrical energy. The conversation of secondary electron emission energy enables one to create a power source with a typical voltage of (10-20) V and a capacity above 2000 KWt×h/kg, this being much higher than for common sources. Moreover, the operation of this type of sources does not require heating to high temperature and use of a refrigerator; this significantly extends their area of application. The experimental studies into secondary emission characteristics of various materials were carried out to optimize binary cell materials of a secondary - emission radioisotope current source. The total current as a function of collector materials was measured. New data on the secondary emission characteristics of certain materials were obtained. It was ascertained that the total binary cell current had an effect upon secondary electron - electron emission. By way of example, a typical power dependence of voltage was investigated for copper collector; the optimum voltage value corresponding to peak power was calculated too. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Нерелятивистская плазменная элeктрoника The researches of kinetic electron emission for creation of new-type current source Article published earlier |
| spellingShingle | The researches of kinetic electron emission for creation of new-type current source Balebanov, V.M. Zhurenko, V.P. Karas, V.I. Karas, I.V. Kononenko, S.I. Moiseev, S.S. Muratov, V.I. Нерелятивистская плазменная элeктрoника |
| title | The researches of kinetic electron emission for creation of new-type current source |
| title_full | The researches of kinetic electron emission for creation of new-type current source |
| title_fullStr | The researches of kinetic electron emission for creation of new-type current source |
| title_full_unstemmed | The researches of kinetic electron emission for creation of new-type current source |
| title_short | The researches of kinetic electron emission for creation of new-type current source |
| title_sort | researches of kinetic electron emission for creation of new-type current source |
| topic | Нерелятивистская плазменная элeктрoника |
| topic_facet | Нерелятивистская плазменная элeктрoника |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81667 |
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