Afterward, the large open end of the capillary was connected to a vacuum, while the tip of the capillary was heated at 650 ⁰C to improve the sealing of the glass around the C fiber by placing the tip inside a resistively-heated W coil (Figure ). Next, a stiff W wire coated on one end with Ag ink was inserted into the capillary through the open end to contact the C fiber. The other end of the W wire, protruding from the capillary, was secured to the capillary using an epoxy adhesive.