Top: the background subtracted pulse-height spectrum obtained for CH₃CH₂OH using the IID system without the grid in front of the detector. The large peak at high energy is due to particles impacting at full beam energy. If losses of heavy fragments passing by the detector due to their high transverse energy would occur, one or two smaller peaks at lower energies would indicate that. It is clear that no loss of heavy fragments are observed. The sharp feature at the leftmost position is due to noise in the detector system. Bottom: the background subtracted pulse-height spectrum obtained for CH₃CH₂OH using the IID system with the grid inserted in front of the detector. The three major peaks are due to detection of fragments containing one, two or three heavy atoms, respectively. The sharp feature at very low mass/energy is due to noise in the detector system mixed with signal from hydrogen fragments.