First,Fast Thermocouple Uses and Works

Fast thermocouple for measuring the temperature of molten steel and the temperature of the melt , the time consumption type thermocouple . Its working principle is based on the thermoelectric effect of the metal , a thermocouple temperature difference generated across the electric measurement of molten steel , and high temperature of molten metal .

Second, Product Specifications and Performance Comparison

Name Type indexing tolerance for temperature measurement time

Best Cap

Platinum and rhodium 30 - platinum and rhodium 6 KB-602P B ± 5 1500-1700 1750 4 ~ 6s
PtRh10 - Platinum KS-602P S ± 5 1400-1600 1650 4 ~ 6s
Platinum and rhodium 13 - Platinum KR-602P R ± 5 1400-1600 1650 4 ~ 6s
Tungsten- rhenium 3 - tungsten rhenium 25 KW-602P W ± 7 1500-1700 1800 4 ~ 6s

Third, the Structure

Fast thermocouple structure which is mainly composed of head temperature even large sheet of paper tube. There are positive and negative dual head thermocouple wire welded wire compensation , the compensation wire wear embedded in the bracket, bracket coat a small paper tube, thermocouple wire quartz support and protection. Outermost equipped with anti- slag cap, all components in concentrated load dump and refractory fillers bonded into a whole, and not removable , so for one-time use .


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Tungsten alloy(heavy alloy) is ideal for shielding against X rays and gamma radiation. The very high density of tungsten shielding (more than 60% denser than lead) allows a reduction in the physical size of shielding components, without compromising their rigidity or the effectiveness of the shielding characteristics.
 
Tungsten heavy alloy shielding is used in applications such as collimator, nuclear shielding, beamstop,  syringe shield, vial shield, isotope container, FDG container, multi leaf collimator etc.

Here are some main applications for nuclear medical radiation shielding:

Whilst X-rays provide information on the structure of the body, PET shows the chemical function of a particular organism. PET involves the injection of FDG (a glucose-based radionuclide) from a shielded syringe into the patient. As the FDG travels through the patient's body it emits gamma radiation which is detected by a gamma camera, from which the chemical activity within cells and organs can be seen. Any abnormal chemical activity may be a sign that tumors are present.

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Radiation shielding is a mass of absorbing material placed between yourself and the source of radiation to reduce the radiation to a level that is safer for humans.

The effectiveness of the material depends on the type of radiation itself, the properties of the material, and the shielding strength or thickness of that material.

Different types of radiation behave in different ways.

According to the NATO Handbook On The Medical Aspects Of NBC Defensive Operations, “Gamma or X radiation constitutes the principal casualty producing form of ionizing electromagnetic radiation associated with nuclear explosions“.

X-ray and gamma photons are essentially identical. The alpha particle however (another type of nuclear radiation from an explosion) while also highly dangerous but is hardly penetrable, and can be stopped by a single piece of paper for example (think of it as a heavy dust particle).

Gamma radiation travels at the speed of light. To protect yourself from gamma radiation resulting from a nuclear explosion, there are just three things to remember. Time, Distance, and Shielding. The first two are very common sensible. That is, get as far away as quickly as you can. Shielding though, requires knowing how much of what type of material is enough…

For radiation shielding, it’s mainly raw mass of material that makes blocking effective. The more shielding, the better. Shielding is measured by what fraction of gamma rays it blocks. If a certain thickness will block half of the incoming radiation, then adding the same thickness again will block half of what’s left (leaving only 1/4 or the original gamma ray intensity), and so on.

Materials are commonly categorized by their ‘halving thickness’, which is the thickness of that material required to block half of the incoming gamma rays.

An overall shield is characterized by its total ‘protection factor’. For example, a shield that only lets 1/1,000 (the modern day ‘acceptable’ amount) of the gamma rays through, has a protection factor of 1000.

To achieve a protection factor of 1,000 the following chart of materials and thicknesses must be used. We’ve saved you the trouble and have factored the proper ‘halving thickness’ values of each material in order to achieve the protection factor of 1,000.

As a rule-of-thumb, for a protection factor of 1000, you want about 375 pounds of mass per square foot of area you’re shielding (this is not a linear function, but this approximation is accurate for protection factor 1,000).

It seems to me that the most practical and economical means to achieve this protection factor is to use the absorption properties of packed dirt. So long as you’re at least 3 feet underground, you’re good to go…

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Effective radiation shielding is imperative to safe operation of modern Medical Cyclotrons producinglarge activities of short-lived radioisotopes on a commercial basis. Like the containment shielding of Medical Linear Accelerators , the optimal shielding design of Medical Cyclotrons demands a careful balance between the radiological, economical and often the sociopolitical factors. One is required to optimize the cost of radiation protection and the cost of radiological health detriment . The cost of radiation protection depends explicitly on the nature of the ionising radiation field produced by the cyclotron, its operational condition, the cost of
shielding material, the level of dose reduction, the projected net revenue from the from the sale of the radioisotopes, and the depreciation rate of the cyclotron facility. The mathematical methods of accelerator shielding optimisation  within the guideline of ALARA  have been reported by various investigators.

The important radioisotopes produced by Medical Cyclotrons for present day diagnostic nuclear
medicine include 201Tl (T1/2= 73.06 h) and67Ga (T1/2= 78.26 h). These radioisotopes are generated by bombarding the thick copper substrates electroplated with enriched parent target materials with 30 MeV protons at ~ 400A beam current. The target bombardments result in the production of intense fields of high-energy neutrons and gamma rays. Therefore, in order to avoid the radio-activation of the cyclotron, the ancillaries and radiation exposure to cyclotron workers and members of the public, the high performance target irradiation stations of modern negative ion Medical Cyclotrons  are housed in separate target vaults made of high density concrete. Thus, the efficient shielding of the target vaults plays the most important role in the radiological safety of the commercial Medical Cyclotron facilities.

The conventional optimisation method for the functions of multiple variables, such as the cost benefit-
analysis of Medical Cyclotron shielding design is too complex and prone to serious pitfalls. Hence, a new
method based on the Genetic Algorithm (GA) was used to solve this problem. The GA is a mathematical technique that emulates the Darwinian Evolution paradigm, also known as the “Survival of the Fittest” strategy.

It is ideally suited to search for a global optimum in a large multi-dimensional solution space, havingdemonstrated strength compared to the classical analytical methods. This paper highlights the application of an interactive spreadsheet macro program for the optimised shielding thickness calculation of the target vault of a Medical Cyclotron. The present optimisation method is based on a Genetic Algorithm search engine and runs on a Pentium 300 MHz Personal Computer in the Windows 98 platform.

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