PENGUKURAN e/m elektron MENGGUNAKAN TABUNG TELEVISI (TV) DAN KUMPARAN HELMHOLTZ

The purpose of this research is to determine the comparison value between e/m of electrons in the use of CRO television tube and use to examine the quality of the experimental method that was is by comparing the experimental method from J. J. Thomson. This research regarded as an experimental method, conducted by measuring the different of light points on the screen television tube to get the radius of electron motion. The data interpreted into a graph to a quaeter radius of current on the coil magnetic field Helmohltz I (amperes). This graph is used to find e/m value of electron and the result is:

A Method Of Interfacing A Transmission Electron Microscope (Tem) With An Automatic Image Analysis System (AIA)

To interface a TEM with an AIA, I replaced the 70mm. camera mounting on the TEM with a fixture incorporating a fluorescent screen and a leaded glass X-ray shield. The phosphor I chose for the screen, “P-12”, is highly efficient and exhibits a spectral peak at the same wavelength as the television tube selected for the job. This tube is a Type 4532 silicon-intensified target (SIT) tube supplied by COHU, Inc. as part of their Type 4250 low-light-level television camera (LLLTV). The composite video signal from this camera is transmitted by cable to the AIA system where it is processed and displayed on a monitor along with information regarding the processing. A second cable returns this processed video signal to the TEM where another monitor allows the microscope operator to see the results. The processing of the signal includes detection of features in the field of view using a grey-level threshold set by the AIA operator, and selection of the desired features thus detected by means of size and shape parameters also supplied by the operator.

Resolution Limits Imposed by Specimen-Electron Interactions

In many respects a scanning microscope is like a television tube; both use a beam of electrons focused to a small spot and scanned in a raster to make a picture. The resolution of the television tube is simply the size of the spot appearing on the tube face. Because there are many ways of measuring the size of an arbitrary intensity distribution, it is difficult to give one number which adequately describes the quality of the image. In order to more precisely characterize the quality of television tubes, Schade used the modulation transfer function (MTF)J The MTF is defined as the ratio of the image spatial frequency distribution to the object spatial frequency distribution. One can easily determine the MTF for a television tube in the following way. To display a delta function on a television tube, one would direct the beam to one point on the screen.