Sample holder

1. A sample holder, comprising:

a base body including a ceramic material and comprising a sample holding face which lies on an upper face of the base body;

a support body including a metal material and comprising an upper face which faces a lower face of the base body;

a first joining layer which joins the lower face of the base body and the upper face of the support body together;

a first through hole extending from a lower face of the support body through the first joining layer to the upper face of the base body, a part of the first through hole located within the base body being at least partly narrower than a part of the first through hole located within the support body and a part of the first through hole located within the first joining layer; and

a porous member located inside the first through hole and joined to the lower face of the base body via a second joining layer.

2. The sample holder according to claim 1 ,

wherein the part of the first through hole located within the base body comprises a first recess located at the lower face of the base body, and a second through hole which opens into a bottom face of the first recess and into the upper face of the base body; and

the porous member is joined to the bottom face of the first recess.

3. The sample holder according to claim 2 ,

wherein the porous member is located entirely inside the first recess.

4. The sample holder according to claim 2 , further comprising:

an insulating tubular member located inside the first through hole, the insulating tubular member covering part of a lower face of the porous member and at least part of an outer peripheral face of the porous member, and extending along the first through hole.

5. The sample holder according to claim 4 ,

wherein an inside diameter of a face of the insulating tubular member in contact with the lower face of the porous member is larger than an inside diameter of a lower end of the insulating tubular member.

6. The sample holder according to claim 4 ,

wherein an upper end of the insulating tubular member is positioned above an upper face of the porous member.

7. The sample holder according to claim 4 ,

wherein the porous member and the insulating tubular member are located apart from each other.

8. The sample holder according to claim 1 , further comprising:

an insulating tubular member located inside the first through hole, the insulating tubular member covering part of a lower face of the porous member and at least part of an outer peripheral face of the porous member, and extending along the first through hole.

9. The sample holder according to claim 8 ,

wherein an inside diameter of a face of the insulating tubular member in contact with the lower face of the porous member, is larger than an inside diameter of a lower end of the insulating tubular member.

10. The sample holder according to claim 8 ,

wherein an upper end of the insulating tubular member is positioned above an upper face of the porous member.

11. The sample holder according to claim 8 ,

wherein the porous member and the insulating tubular member are located apart from each other.

12. The sample holder according to claim 1 ,

wherein the porous member and the second joining layer are configured to include a second recess comprising an inner peripheral face being continuous with the part of the first through hole located within the base body.

13. The sample holder according to claim 1 , further comprising:

a third recess extending from the upper face of the base body through the second joining layer to the porous member.