On‐line display aids for the automated measuring of bubble chamber film at Fermilab energies

An operator uses a new video display with separately adjustable magnifications along the x and y axes to assist the measuring of Fermilab 76.2‐cm bubble chamber film by our computer controlled measuring device (PEPR). The differential magnification enlarges angles and curvatures of the many fast‐forward tracks present in events of energy 100 GeV or greater. The display is used by the PEPR operator to view complicated events and guide the computer track measurement and to make manual measurements of obscured tracks which are too difficult for the automatic system to handle. We present results on 2900 events containing neutral strange particles and gamma conversions in π− p collisions at 147 GeV/c.