JPH0584016U - Cooling device for photomultiplier tubes - Google Patents

Abstract

(57) [Abstract] [Purpose] To enable effective cooling of the photomultiplier tube with a unique cooling mode that does not cause fogging on both sides of the light transmission window.
Furthermore, the cooling device as a whole should be downsized. [Arrangement] A photomultiplier tube 2 is provided in the vacuum chamber 1,
A Peltier element 11 in which a metal block 10 for heat conduction is brought into close contact with a heat absorption surface is provided, a heat radiation surface thereof is provided inside the chamber and a metal block is brought into close contact with a photomultiplier tube, and the heat radiation surface of the Peltier element is cooled. Means 12 are provided in the chamber.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improved cooling device for a photomultiplier tube.

[0002]

[Prior Art]

 The photomultiplier tube is used for optical communication in the infrared region, for example, and it is necessary to cool the photomultiplier tube in order to reduce thermal noise (dark current noise). In FIG. 4 showing a conventional cooling device for this purpose, reference numeral 21 denotes a double-walled chamber in which a space P for accommodating a photomultiplier tube 22 is formed. A light transmitting window 24 is provided at the corresponding portion, and a heat insulating material 25 is filled inside the double wall.

Reference numeral 26 is a heater for preventing dew condensation on the light transmission window 24, and 27 is a Peltier element in which a metal block 28 for heat conduction is closely attached to a heat absorption surface. The metal block 28 is connected to the photomultiplier tube 22. It is provided on the side opposite to the light transmission window 24 in a state of being relatively rolled up. 29 is a power supply for the heater, and 30 is a power supply for the Peltier element. Reference numeral 31 denotes a water-cooling type cooler for the heat radiation surface of the Peltier element 27, which is formed by connecting cooling water supply / drain pipes 33, 34 to a jacket 32 which is in close contact with the heat radiation surface.

In the above-mentioned configuration, by supplying an electric current to the Peltier element 27 so that the metal block 28 side becomes a heat absorbing surface and supplying cooling water to the jacket 32, the air in the multiplier built-in space P is Is used as a cooling medium to cool the photomultiplier tube 22. On the other hand, moisture in the air is condensed by the above-mentioned cooling, and the light transmission window becomes cloudy due to the condensation of the moisture, but since the light transmission window 24 is heated by the heater 26, the clouding is prevented.

[0005]

However, in the above-mentioned configuration, the chamber 21 is inevitably increased in size and air is used as a cooling medium because of the heat insulating form in which the chamber 21 is filled with the heat insulating material 25. Therefore, the heater 26 for preventing dew condensation is indispensable. Furthermore, not only the photomultiplier tube 22 but also the air has to be cooled, and the heater 26 is equipped, which contributes to the capability. There was a problem requiring a large cooler 31.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cooling device for a photomultiplier tube in which the above inconveniences are alleviated by a simple and rational improvement. I am trying.

[Means for Solving the Problems]

 In the cooling device for a photomultiplier tube according to the present invention, which has achieved the above-mentioned object, a Peltier element in which a metal block for heat conduction is closely attached to a heat absorption surface, and its heat radiation surface is inside the chamber and the metal The block is provided in close contact with the photomultiplier tube, the cooling means for the heat radiation surface of the Peltier element is provided in the chamber, and the space containing the multiplier tube in the chamber is placed under vacuum.

[0007]

[Action]

 According to the above characteristic configuration, the photomultiplier tube is directly cooled by the Peltier element via the metal block under a vacuum in which water that causes dew condensation does not exist.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cooling device for a side-on type photomultiplier tube. In the figure, reference numeral 1 denotes a metal chamber for incorporating a photomultiplier tube, a box-shaped main body 1a, and a seal ring at an opening of the main body 1a. The main body 1a is provided with a connecting portion c for a vacuum pump or the like for placing the multiplier built-in space P under vacuum, which is made up of a lid 1b which is fixed by a screw b via a.

Reference numeral 2 denotes a photomultiplier tube, which is suspended and held by two metal fittings 4 via a cooler 3 attached to the inner surface side of the lid body 1b, and is connected to a power source derived from a socket 5 and is used as a power source. The lead wires d and e for taking out the signal are connected to the connectors 6 and 7 provided on the outer surface of the lid 1b. Reference numeral 8 denotes a light transmission window provided in the main body 1a of the vacuum chamber 1 so as to face the light detection portion 9 of the photomultiplier tube 2.

As shown in FIG. 2, the cooler 3 includes a metal block 10 for heat conduction that is in close contact with the photomultiplier tube 2, a heat absorbing surface is in close contact with the metal block 10 and a heat radiating surface is a cover. A radiating fin type cooling means 12 for the heat radiating surface of the Peltier element 11 inside is provided on the outer surface of the lid 1b. Incidentally, 13 is a power source for the Peltier element.

According to the above configuration, the light transmission window 8 is connected to the heat radiation side of the Peltier element 11 via the vacuum chamber 1, and the temperature of the window itself becomes higher than the ambient temperature, so that the outer surface of the window becomes cloudy. In addition, since the multiplier built-in space P is placed in a vacuum in which there is no moisture that causes dew condensation, the inner surface of the light transmission window 8 is not fogged, and therefore condensation is prevented on the light transmission window 8. No heater is required. In addition, it is possible to directly cool the photomultiplier tube 2 by the Peltier element 11 through the metal block 10 without performing extra cooling such as air cooling, and to eliminate the need for the heater. Therefore, the photomultiplier tube 2 is effectively cooled, and the ultimate cooling temperature can be lowered without increasing the cooling capacity. Further, since the chamber 1 is made of metal and has a vacuum heat insulation cooling mode in which a heat insulating material is not provided, downsizing of the entire cooling device can be achieved.

Since the cooling means 12 is of an air-cooling type in which fins f are integrally connected to the outer surface of the lid 1b, the cooling device is easy to handle and the water supply / drainage system is installed. Since it is not necessary to use the water cooling type cooling means shown in FIG. 4, it is possible to replace the fins f with the water cooling type cooling means shown in FIG.

FIG. 3 shows a cooling device for a head-on type photomultiplier tube, in which a photomultiplier tube 2 having a photodetection section 9 formed on the head side is built in the vacuum chamber 1 in a horizontally suspended state. The light transmission window 8 is formed in the vacuum chamber 1 so as to face the light detection portion 9. Since other configurations are the same as those shown in FIG. 1, the same components are designated by the same reference numerals. The duplicate explanation will be avoided.

[0014]

[Effect of the device]

 As described above, according to the cooling device of the present invention, the outer surface of the light-transmitting window is not fogged, and the inside of the multiplier tube is placed under a vacuum in which there is no moisture that causes dew condensation. In addition to the fact that the inner surface is not fogged and that the photomultiplier tube is directly cooled without extra cooling such as air cooling, the heater for preventing dew condensation on the light transmission window is not required. Cooling of the multiplier tube is effectively performed, and the ultimate cooling temperature can be lowered even with the same cooling capacity as the conventional one. Furthermore, by adopting a cooling mode under vacuum heat insulation, the miniaturization of the entire device was achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a cooling device for a photomultiplier tube.

FIG. 2 is a vertical plan view of a cooler.

FIG. 3 is a vertical sectional side view showing a cooling device for a photomultiplier according to another embodiment.

FIG. 4 is a vertical cross-sectional side view showing a conventional cooling device for a photomultiplier tube.

[Explanation of symbols]

1 ... Chamber, 2 ... Photomultiplier tube, 8 ... Light transmitting window, 9 ...
Light detector, 10 ... Metal block, 11 ... Peltier element, 12
… Cooling means.

Claims (1)

[Scope of utility model registration request] 1. A cooling device for a photomultiplier tube which is housed in a chamber with a light detecting portion facing a light transmitting window, wherein a Peltier element having a heat absorbing surface closely contacted with a metal block for heat conduction is provided. Of the Peltier element is provided in the chamber, and the metal block is provided in intimate contact with the inner surface of the chamber, and the metal block is provided in close contact with the photomultiplier tube. A photomultiplier tube cooling device, characterized in that is placed under vacuum.