原文由 denx5201314 发表:
一直在这里看来看出,发现大家的发言也不多,关于辉光的几乎没有,也不知道辉光是不是属于这个版块,其实我很想和其他的辉光人员做个认识,因为我有一些问题想问下.就辉光目前的发展,应用,实际的数据想有个交流.如果大家愿意,可以在这里留言.

2.    Principles of the GDOES techniques
This application note focuses on the performance of the  Spectruma GDA 750 HP for the bulk analysis of cast irons. We will, however, demonstrate the interest of  keeping the depth profile capability even for bulk analyses of  cast iron. We will further compare the performance of  the GDOES technique to the traditional  Spectro Cast instruments.
2.1.    Glow discharge light source.
A hollow anode glow discharge chamber serves as the light source for the spectrometer. The two electrodes of the discharge cavity are designed as a tubular grounded copper tube and the flat sample to be analysed. In fact, the sample closes the discharge cavity: Sample introduction is therefore extremely simple. The electrical power is supplied directly to sample. A  regulated negative voltage 900 Volts DC is supplied. The carrier gas within the discharge cavity is high purity Argon (5.6 or higher). The Argon pressure in the cavity is maintained at about 4 Pascal. The Argon flow and as a consequence the Argon pressure is regulated to maintain a discharge current of 40 mA. Under these condition a flow of about 0.2l/min sweeps the cavity to ensure a clean Argon atmosphere during the analyses process.
The analytical figures of merit of the GDOES technique are closely linked to the physics of the glow discharge.
A plasma is created within the tubular grounded anode. The electrical power to ignite and maintain the plasma is fed through the sample, which acts as the cathode. Argon ions and free electrons are generated in the plasma (1). The potential difference between the plasma and the sample accelerate the Argon ions towards the sample(2). The ions bombard the sample surface with an average kinetic energy of 100 eV (3). This bombardment creates a sputtering process, atoms from the sample surface leave the sample lattice. In addition to the atoms some free electrons, called secondary electrons, are generated during the sputtering process as well (4). The secondary electrons are accelerated towards the plasma and maintain the plasma activity. The atoms diffuse towards the plasma. Here they may be excited (7) or ionised through collisions with free electrons, Argon ions or meta-stable Argon atoms (5). The excited analyte atoms subsequently relax to the energetic ground state by emission of characteristic photons (6). The characteristic photon spectrum is observed through the observation window.
In fact, the analyte atoms, after being sputtered from the surface, are diluted in the Argon atmosphere of the plasma and excited as single atoms. It is this separation of sputtering and excitation as well as the dilution in the Argon plasma, that makes GDOES analyses widely independent of matrix effects. The low density of analyte atoms leads also to a reduction of self-absorption and allows therefore the observation of  mainly straight calibration lines.
The discharge chamber is designed to achieve flat sputter craters. The average energy of  Argon ions bombarding the sample surface is only 100 eV. At this low energy the Argon ions do not penetrate deeply into the sample latice. Only atoms from the outmost atomic layers are removed from the sample surface. The combination of flat crater bottoms and moderate ion energy assures a good depth resolution of the GDA 750. It allows to characterise the chemical composition of the sample layer by layer, from the surface into the core material.