Transport of material to Uppsala

The helium-recoil spectrometer was intended for the detection and measurement of α particles from coherent interactions of high-energy particles with ⁴He nuclei. It allowed the determination of the magnitude and the direction of the momenta of the helium recoils from interactions in a pressurized gas target. The apparatus was in operation in the South Hall from 1969-71 where a 8 GeV pion beam was directed at the target. The results of this experiment was later (1971) presented for the region of squared four-momentum transfers between −0.05 and −0.5 (GeV/c)². The directions of the scattered pions and α particles were measured with spark chambers and the momentum of the αs as obtained from pulse-height and time-of-flight measurements. The results were so compared with calculations from the Glauber theory, showing good agreement over the whole momentum-transfer range including the interference-dip region.