Neutral aluminum clusters Aln (n up to 30) have been generated using laser vaporization and pulsed molecular beam techniques. The neutral clusters are photoionized by a 193 nm excimer laser and detected by a Wiley-McLaren time of flight (TOF) mass spectrometer. 2p, 1g and 3s electronic shell closings are revealed at Al13,Al19 and Al23, respectively. Geometric effects also contribute to stability the intensity discontinuities, at least within the present investigated cluster size range. Neutral aluminum clusters Aln (n up to 30) have been generated using laser vaporization and pulsed molecular beam techniques. The neutral clusters are photoionized by a 193 nm excimer laser and detected by a Wiley-McLaren time of flight (TOF) mass spectrometer. 2p , 1g and 3s electronic shell closings are revealed at Al13, Al19 and Al23, respectively. Geometric effects also contribute to stability the intensity discontinuities, at least within the present investigated cluster size range.