12 includes a plurality of openings 20 fig4 which extend from a lower surface 19 to a side surface 21 the piston 14 extends through an opening 18 creating an annular space into which a seal 22 fits an end 16 of the piston 14 is rounded alternatively the end 16 may have a different shape such as for example a shape having a reduced diameter as compared with the remainder of the piston 14 the piston 14 is extended through the opening 18 to push against and elastically deform a tape 34 supported by the hoop 30 described in detail below the tape 34 has an adhesive surface to which a plurality of chips 40 are adhered the hoop 30 which is shown in greater detail in fig5 6 includes a hoop frame 32 surrounding the periphery thereof a tape 34 extends across the hoop 30 and is affixed to a surface 33 of the hoop frame 32 the tape 34 has an adhesive side facing away from the surface 33 further the tape 34 is affixed to the surface 33 by way of an adhesive strip corresponding to the circular profile of the hoop frame 32 and positioned on the side of the tape 34 facing toward the surface 33 or alternatively by way of a separate adhering structure the separate adhering structure could include clamps clips or a layer of glue or other adherent being located on the tape.