A bore tube for use in an imaging apparatus has a first tube and a second tube. A shaft hole of a lever is fit on a shaft that projects from a front end of the cover. It is then determined whether a demand for the desired EBR exceeds a supply of the EBR. The semiconductor device also includes one or more openings through the N-type substrate that extend from a back-side of the N-type substrate to the P-type layer and a back-side contact on the back-side of the N-type substrate and within the one or more openings such that the back-side contact is in physical and electrical contact with the P-type layer. If necessary, the wafer portion on which the devices are fabricated may be thinned. The left and right fences slide on the top work surface in a front to rear direction and a side to side direction.