1. The problem statement, all variables and given/known data The electron enters a straight pipe of circular cross section (radius r). The tube is bent at a radius R≫r by the angle α and then is aligned back again. Find the probability that the electron will jump out 2. Relevant equations Tunneling probability in WKB approximation. 3. The attempt at a solution Unsure of what the potential should be and the effect that the bend has.