JPS5868856A - Ion source - Google Patents

Abstract

PURPOSE:To keep constant and ionization of an ionized material by providing a means that heats the ionized material. CONSTITUTION:The argon ions generated from an ion gun 1 and accelerated by it are incident on a bombardment chamber 3 that is filled with argon gas. A part of them collides with argon gas, is deprived of charge, changes into a high speed neutral particle, is introduced in an ionized box 5, and is incident on a target 10 that is welded on a tungusten wire 9. The surface of the target is coated with a sample in which an ionized material is mixed and the sample is evaporated and ionized when it is made to collide with a neutral argon atomic beam. Since the target 10 and the sample are heated by applying current to the tungsten wire 9, the supply of the material on the surface of the sample is activated. As a result, an event in which the amount of the ionized material is reduced with a lapse of time hardly occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion source suitable for use in a mass spectrometer,
In recent years, a mixed sample of, for example, glycerin and a substance to be ionized has been completely coated on a conductive substrate, and this sample has been ionized by high-speed neutral particles. An ion source that bombards neutral particles and uses the energy of the neutral particles to knock out the substance to be ionized and further ionize it is attracting attention.When this ion source is used as an ion source for a mass spectrometer, The ionization energy is low and the ionization is soft, the generation rate of not only positive ions but also negative ions is high, and since neutral particles are bombarded with the sample, there is no charge-up and even insulating samples can be easily ionized. It has many excellent features such as:

However, in this ion source 1, although the sample is continuously bombarded with constant energy and neutral particles, the amount of ionization of the substance to be ionized gradually decreases with the passage of time. Accurate sample mass analysis becomes difficult. This is because over time, the surface of the sample that is bombarded by neutral particles is dominated by substances that tend to separate from the sample due to the bombardment of these particles. It is assumed that the influence of contamination on the sample surface cannot be ignored.

The overall object of the present invention is to provide an ion source that can maintain constant ionization of a substance to be ionized.

The present invention is characterized in that an ion source that ionizes a substance to be ionized by bombarding it with high-velocity neutral particles includes a means for heating the substance. According to Kazumi Ken I by the present inventor, this heating improves the mobility of the ionized substance and activates the movement of the ionized substance from the inside of the sample to the surface part of the sample that is bombarded by neutral particles. The ionization of the deionized substance could be maintained constant for a considerable period of time.

An embodiment of the present invention will be described in detail below based on the accompanying drawings.

In the figure, 1 is an argon ion gun, and argon ions generated in the ion gun are accelerated by an accelerating electrode 2. This accelerated high-velocity argon ion beam 1 enters the collision chamber 6 filled with argon gas, and a portion of it collides with the argon gas, loses its charge and becomes high-speed neutral particles. .

An electrostatic deflection plate 4 is disposed at the bottom of the collision chamber 6, and the argon ions that have passed through the collision chamber 3fc are deflected and removed by the deflection plate 4, and only neutral particles are transferred to the deflection plate 4.
The ionization box 5 is placed at the bottom of the ionization box 5. A base 6 is disposed inside the ionization box 5, and metal struts 7.8 are fixed onto the base, and the tungsten IIi! 9 is fixed. An IJ target 10 made of copper, for example, is spot welded onto the tungsten wire 9. The pillar 7
, 81: are connected to the heating power source 11 and 1. As a result of f:, the tungsten wire 91 is heated according to the heating current supplied from the nuclear power source 11. 6. An ion accelerating voltage of, for example, about 3 KV is applied to the target 10 etc. from the power source 12 and the voltage is 0.0 KV. Furthermore, this accelerating voltage is applied to the voltage divider 16.
The voltage is divided by the slit voltage and applied to the group 14.

In the configuration as described above, a considerable amount of rfI+ of the argon ions generated and accelerated from the ion gun 1 mainly collides with argon atoms in the collision chamber 6 and loses electric charge. A mixed beam of argon atoms and argon ions that have not lost their charge in the collision chamber is obtained from the collision chamber 6, but the argon ions are deflected by the electrostatic deflection plate 4, resulting in Only the +/IE argon atomic beam is incident on the target 10. IJ is applied to the surface of the target, for example, by mixing the entire substance to be ionized in glycerin [
-A sample is coated and the R'l sample is bombarded by a neutral argon atomic beam. The material on the surface of the sample that has received the impact is evaporated and ionized. The nuclear ionized substance is extracted by the slit electrode group 14, further accelerated by 1°, and guided to the mass spectrometer.

Here, the sample surface portion 1-1 bombarded by the neutral argon atomic beam changes over time, and the amount of ionized material decreases. However, in this embodiment, the tungsten wire 9 is heated by supplying the full amount of current, and the target 10 and the entire sample coated on the target 10 are heated to about 200°C to 300°C. The mobility of the fractured ionized substance is improved, and the supply of this substance to the part of the sample surface that is bombarded by the argon atomic beam is increased. As a result, the above-described phenomenon 1 in which the amount of ionized substances decreases with the passage of time hardly occurs, and dense mass spectrometry of ionized substances can be performed.

Although the present invention has been fully described in detail above, the present invention is not limited to the first embodiment described above and can be modified in many ways. For example, in order to heat the substance to be ionized, a tungsten wire to which a target is fixed is heated by passing an electric current through it, but an f-E type heater is placed close to the target (sample), and the sample is heated by the radiant heat from this heater. 1 to heat
It is also possible to use other heating means.

[Brief explanation of drawings]

Attached drawings (J This is a diagram showing a complete example of the present invention. 1: Ion gun, 2: Acceleration city 1 pole, 3: Collision chamber, 4: Silence)
i! m direction plate, 5: ionization box, 6: group r), 7° 8: pillar, 9: tungsten wire, 10: target, 11: heating power source, 12: power source, 16: molecular E device, 14 Nislit electrode group. Patent applicant JEOL Ltd. Representative Tadashi Kasei

Claims (1)

[Claims] An ion source that ionizes a substance to be ionized by bombarding it with high-velocity neutral particles, the ion source comprising means for heating the substance.