JPS6097289A - Apparatus for measuring absorption energy distribution - Google Patents

Abstract

PURPOSE:To make it possible to measure an absorption dose or absorption energy distribution with high accuracy without being affected by radioactive rays or an electromagnetic wave, by surrounding a heat sensor by an isolation film. CONSTITUTION:A heat sensor 1 for detecting the rising in the temp. of a liquid is surrounded by an isolation film 2. This isolation film is one inferior to heat conductivity and withstanding heat such as a Kapton film and, at the same time, it is necessary to constitute said film 2 from a substance having radiation resistance stronger than that of said Kapton film and hot corroded even by a liquid. In addition in order to reduce the disturbance of a radiation field in a liquid caused by the presence of the isolation film, a substance near to a liquid in an effective atomic number and capable of being made thin as possible is desirably used.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is based on the fact that when a substance is irradiated with radiation, electric waves, or waves, the absorbed energy of the substance can be determined by measuring the temperature rise at an arbitrary position within the substance. This invention relates to an absorbed energy distribution measuring device that can measure the spatial distribution of .

The method using a calorimeter, which attempts to determine the energy absorbed by a material irradiated with radiation or electromagnetic waves from the temperature rise of that material, is one of the oldest radiation measurement methods.

However, this method using a calorimeter had two drawbacks. The first drawback is that the temperature rise of the irradiated material is extremely small, and no improvement in measurement accuracy can be expected. The second drawback is that the thermal energy obtained by the material is diffused throughout the material by thermal conduction or convection, so the averaged absorbed energy is measured, making it difficult to measure the absorbed energy distribution. ”2 The second drawback is that materials irradiated with beam-like radiation or electromagnetic waves
If there is a large difference in absorbed dose (energy) depending on location, this simply means that the conventional method using a calorimeter cannot be used. The first drawback is that if a sufficient amount of radiation is irradiated and the temperature of the material is raised to a few degrees Celsius, the sensitivity of current thermal sensors would be 0.1%.
The following measurement accuracy can be expected, and it is easily possible to raise the temperature by several degrees Celsius by irradiating high-intensity radiation using an accelerator or the like. However, in this case as well, if we do not take into account the second drawback above, the 4.
] It is not constant. Although it is essential to overcome the second drawback, especially in order to measure the absorption energy distribution in a substance by calorimetric methods, no such calorimeters exist to date.

This invention has been made in view of the above points, and eliminates the second drawback, which is a serious obstacle when measuring the spatial distribution of absorbed energy of a fluid material that has been irradiated with radiation or electromagnetic waves. , obtain the absolute value of absorbed energy at any position within the substance, and thereby radiation cancer treatment,
Alternatively, it aims to improve the measurement accuracy of absorbed dose or absorbed energy in thermal cancer treatment. This invention will be explained below.

FIG. 1 shows an embodiment of the present invention, in which a liquid such as water is selected as the substance to be irradiated. In this figure, 1
2 is a thermal sensor that detects a rise in temperature of the liquid, and 2 is an isolation membrane surrounding the thermal sensor 1. The isolation membrane 2 needs to be made of a material that has poor thermal conductivity and is resistant to heat, such as a Kapton membrane, but also has stronger radiation resistance and is not corroded by liquid. In addition, in order to minimize the disturbance of the radiation field in the liquid due to the presence of the isolation membrane 2, the effective atomic number is close to that of the liquid.
Moreover, it is desirable to use a material that can be made sufficiently thin. The isolation membranes 2 can be arranged in close contact with each other in a honeycomb structure as shown in FIG. On the other hand, they can also be arranged at arbitrary intervals like the rungs of a ladder.

To measure the absorbed energy distribution using the thermal sensor 1 shown in FIGS. 1 and 2, a honeycomb structure having the isolation membrane 2 as a partition wall is placed horizontally in water, and heat convection occurs.

Reduce heat diffusion. Thermal sensor 1 is located in the horizontal direction inside the cylinder.
That is, the temperature distribution in the direction of arrow A is measured.

Further, the radiation or electromagnetic waves R can be made not only incident in the direction of arrow B from a direction perpendicular to the isolation membrane 2, but also in a parallel direction or at an arbitrary angle with respect to the isolation membrane 2. Furthermore, Figures 1 and 2
In the figure, the isolation film 2 is disposed in the direction of propagation of the incident radiation or the 1L magnetic wave, but it can also be formed by stacking a plurality of layers downward.

An important point of this invention is that the thermal sensor 1 is surrounded by a radiation-resistant diaphragm 2, which prevents thermal convection and thermal diffusion of the liquid.
By knowing the temperature A of the liquid at that position, the absorbed energy distribution can be measured. In actual use, the complete set of equipment and the irradiated material as shown in Figures 1 and 2 are stored in a container of any shape.
It is necessary to suppress the exchange of thermal energy between the outside air and the irradiated material as much as possible.

As explained above, in addition to suppressing thermal convection and thermal diffusion of the surrounded irradiated material by surrounding the thermal sensor with an isolation film, the present invention is also applicable to the type and energy of incident radiation, Limited to the type and amount of the substance, the material and shape of the isolation membrane, its dimensions, the placement of the thermal sensor with the membrane, the geometrical relationship between the thermal sensor and the incident radiation or electromagnetic waves, and the material and shape of the storage container. It has the advantage of being able to measure the absorption energy distribution of the irradiated material without being exposed to radiation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the invention, and FIG. 2 is a perspective view showing another embodiment of the invention. In the figure, 1 is a thermal sensor, 2 is a partition pI# membrane, and R is radiation or electromagnetic waves.

Claims (1)

[Claims] a container for containing an arbitrary amount of any fluid material that is irradiated with radiation, and a container for detecting a temperature increase due to absorption of energy of the irradiated radiation or electromagnetic waves by the fluid material; Absorbed energy distribution measurement characterized in that one or more thermal sensors surrounded by a thin layer of isolating material for suppressing heat diffusion are installed at any position within the container. Device.