CEM ASSEMBLY AND ELECTRON MULTIPLIER DEVICE

• US 20200135439A1
• Filed: 10/28/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: ENDO, Takeshi, KOBAYASHI, Hiroshi
• Granted Patent: US 10,685,822 B2
• Time in Patent Office: Days
• CPC Class Codes: H01J 43/12 Anode arrangements
• CPC Class Codes: H01J 43/24 Dynodes having potential gradient along their surfaces
• CPC Class Codes: H01J 43/30 Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for

Abstract

According to an embodiment, in a CEM assembly and the like, it is possible to reduce a size of a voltage supply circuit configured to stabilize a voltage to be applied to a channel electron multiplier. The CEM assembly includes a CEM and a voltage supply circuit. The CEM includes an input electrode, a multiplication channel, and an output electrode. The voltage supply circuit includes a power source unit and a constant voltage generation unit. A potential of an input electrode A is set by an electromotive force generated by the power source unit. The constant voltage generation unit includes a constant voltage supply unit configured to cause voltage drop. A target potential set at an output-side reference node is maintained by the voltage drop of the constant voltage supply unit.

Claims

1. A CEM assembly comprising:

(1) a channel electron multiplier including;

a multiplication channel having an input end for taking charged particles in, an output end for emitting secondary electrons, and a secondary electron emission layer continuously provided from the input end toward the output end;

an input electrode provided at the input end in a state of being in contact with the secondary electron emission layer; and

an output electrode provided at the output end in a state of being in contact with the secondary electron emission layer; and

(2) a voltage supply circuit configured to apply a predetermined voltage between the input electrode and the output electrode, the voltage supply circuit including;

a first terminal set to a first reference potential;

a second terminal connected to the input electrode;

a third terminal connected to the output electrode;

a fourth terminal set to a second reference potential;

a power source unit disposed between the first terminal and the second terminal to generate an electromotive force for ensuring a potential difference between the first terminal and an input-side reference node, the input-side reference node being set to the same potential as the potential of the input electrode via the second terminal; and

a constant voltage generation unit disposed between the third terminal and the fourth terminal to hold a target potential for adjusting a potential of the output electrode, the constant voltage generation unit having an output-side reference node set to the target potential and located between the third terminal and the fourth terminal, and a constant voltage supply unit provided to cause voltage drop for ensuring a potential difference between the fourth terminal and the output-side reference node.

2. The CEM assembly according to claim 1, wherein

the constant voltage generation unit further includes

a first resistor disposed between the input-side reference node and the output-side reference node, and

a potential fixing element provided to eliminate a potential difference between the output electrode and the output-side reference node via the third terminal.

3. The CEM assembly according to claim 2, wherein

the constant voltage supply unit further includes a second resistor disposed between the output-side reference node and the fourth terminal.

4. The CEM assembly according to claim 3, wherein

a resistance value of the first resistor is higher than a resistance value of the second resistor.

5. The CEM assembly according to claim 3, wherein

a resistance ratio between the first resistor and the second resistor falls within a range of 100:

1 to 2;

1.

6. The CEM assembly according to claim 2, wherein

the constant voltage supply unit further includes a Zener diode disposed between the output-side reference node and the fourth terminal.

7. The CEM assembly according to claim 2, wherein

the potential fixing element includes any one of a MOS transistor, a FET, and a bipolar transistor.

8. The CEM assembly according to claim 1, wherein

the constant voltage supply unit further includes one or more IC units connected in series between the output-side reference node and the fourth terminal, and

each of the IC units includes a shunt regulator IC, a third resistor, and a fourth resistor, the third resistor and the fourth resistor being connected in series between an input end and an output end of the shunt regulator IC at a predetermined resistance ratio.

9. The CEM assembly according to claim 1, wherein

the multiplication channel further includes:

a structural body provided to support the secondary electron emission layer, the structural body being comprised of an insulating material; and

a resistive film provided between the secondary electron emission layer and the structural body.

10. The CEM assembly according to claim 9, wherein

the insulating material includes ceramic or glass excluding lead glass.

11. The CEM assembly according to claim 1, wherein

a resistance value of the multiplication channel located between the input electrode and the output electrode is less than 10 MΩ

.

12. An electron multiplier device comprising:

the CEM assembly according to claim 1; and

an anode disposed so as to face the output end of the channel electron multiplier constituting a portion of the CEM assembly.