A sample of pure gaseous bromine, \(\text{Br}_2\text{(g)}\), is analyzed in a mass spectrometer. The ionization chamber produces both singly charged monatomic fragment ions, \(\text{Br}^+\), and intact molecular ions, \(\text{Br}_2^+\), yielding the mass spectrum shown below.

Based on the mass spectrum, which of the following best explains why the peak at \(m/z = 160\) is approximately twice as intense as the peaks at \(m/z = 158\) and \(m/z = 162\)?