Length and Straightness of the Tubes for the BOS Prototype Chamber

We have measured length and straightness of 50 tubes of 3.8~m length, after cleaning, wiring and testing from a batch that was used in the construction of the BOS prototype chamber. The specifi ed length (aluminum tube only, without endplug) was 3800~mm with a tolerance of $\pm$1~mm. We found a mean value of (3805$\pm$2)~mm with a standard deviation of (0.3$\pm$0.1)~mm. The measureme nts of the straightness of the 50 BOS MDT tubes gave a mean of the maximum deviation of 150~$\mu$m for 10 measured points along the tubes at 0$^{\circ}$, 90$^{\circ}$, 180$^{\circ}$ and 270$^{\circ }$ around the tube diameter and a mean value of all deviations of 20~$\mu$m with a measuring accuracy of 10~$\mu$m.