پديدآورندگان :
Ghorashi Seyed Alireza sar.ghorashi@isrc.ac.ir Spectrometry and Microelectronic Devices Department, Institute of Materials and Energy, Iranian Space Research Center, 7th Km Imam Khomeini St., Esfahan, Iran; , Alinoori Amir Hossein - Spectrometry and Microelectronic Devices Department, Institute of Materials and Energy, Iranian Space Research Center, 7th Km Imam Khomeini St., Esfahan, Iran , Hajialigol Saeed - Spectrometry and Microelectronic Devices Department, Institute of Materials and Energy, Iranian Space Research Center, 7th Km Imam Khomeini St., Esfahan, Iran , Amoozgar Fariborz - Spectrometry and Microelectronic Devices Department, Institute of Materials and Energy, Iranian Space Research Center, 7th Km Imam Khomeini St., Esfahan, Iran , Sheikhbahaee Hamed - Spectrometry and Microelectronic Devices Department, Institute of Materials and Energy, Iranian Space Research Center, 7th Km Imam Khomeini St., Esfahan, Iran
چكيده فارسي :
Ion Mobility Spectrometry (IMS) is a technique detecting charged particles or ions according to their size and not their chemical properties. Due to this fact it can not be used to make meticulous identification of unknown compounds; however, it has the potential to make rapid measurements of certain compounds. Therefore, it can be employed in some security checkpoints such as airports for detecting explosives, narcotics, and chemical warfare agents [1]. Considering the fact that ion mobility spectrometers have a single drift chamber, they can not be used with both positive and negative ions and the utility of these devices would be limited. That is, spectrometers detecting positive ions are functional for measuring drugs and warfare agents while they cannot the capability of detecting explosives which produce negative ions. As a result, for detection of both classes of materials, we need two separate spectrometers which causes an enormous increase in size, weight, depreciation as well as repair and maintenance costs [2]. On the basis of the above, a need remains for an IMS device that can detect both positive and negative ions. In this work an attempt was made to design and construct a 2-mode IMS which ameliorates the demerits of the prior systems. The desired system comprises a sample introduction device which has been designed, constructed and tuned for both narcotics and explosives. This devise is connected directly to an IMS cell with adjusted flows and temperature. For producing and applying both positive and negative electrical fields in the cell, we need a high voltage power supply with an innovative structure which has been designed and built in this work exclusively. In addition, all of the other parts including amplifier, pulse generator and software are consistent for both modes of operation. The system performance was verified in both two modes and its correctness was proved.
