Question 26.9: Stationary Targets versus Colliding Beams Compare the energi...
Stationary Targets versus Colliding Beams
Compare the energies available from a 1.0-TeV proton accelerator when (a) two 1.0-TeV protons collide head-on and (b) a 1.0-TeV proton strikes another proton in a stationary target.
ORGANIZE AND PLAN For colliding particles each with kinetic energy K, the total available energy is 2K. For the stationary-target experiment, the energy is given by Equation 26.3:
E=(m1c2+m2c2)2+2m2c2K.
Known: Proton rest energy mc2=938 MeV=0.938 GeV; K=1.0 TeV=1000 GeV.
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Here it’s convenient to express all energies in GeV. The total energy of the colliding beams is 2K = 2000 GeV. For the stationary-target experiment,
E=(m1c2+m2c2)2+2m2c2 K.
E=(0.938 GeV+0.938 GeV)2+2(0.938 GeV)(1000 GeV).
= 43.4 GeV.
REFLECT The colliding beams provide almost 50 times the energy of the stationary-target experiment!