Mass Analysis of the Secondary Particles Produced by the 25-Gev Proton Beam of the Cern Proton Synchrotron

Abstract

We present here some results of a mass analysis of the secondary particles produced at 15.9° to the circulating beam in an aluminum target bombarded by 25-Gev protons in the CERN proton synchrotron.The apparatus (Fig. 1) essentially was a mass spectrometer where the momentum of a particle was determined in the magnet M and its velocity was measured by timing the particle between counters 1 and 3. The distance between 1 and 3 was 27 m, which corresponds to a time of flight of 90 nanoseconds for light. Counter 3 was at 61 m from the target and subtended at the target a solid angle of 1.61 xlO" 6 steradian. A time sorter, 1 preceded by zero-crossing circuits and gated by the coincidence 123, was used to display the time difference between the pulses in counters 1 and 3, with the pulses in 1 suitably delayed. The total time range displayed in the 100 channels of the time sorter was ~15 nsec.Typical spectra for positive and negative particles are shown in Fig. 2. The pion peak (which in fact contains a small contamination of muons and electrons) indicates that the time resolution of the apparatus is about 0.9 nsec. The greater width of the proton peak is caused by the spread in flight times due to the finite momentum band (Ap/p ~ 3%) accepted by the magnet.The results obtained for negative particles Gov ^Proton BeamShielding Wall

Deuteron Production in High-Energy Collisions

“…1 Deuterons have been observed also in cosmic-ray emulsion work 2 and were interpreted as belonging to the high-energy tail of evaporation.…”

Charge-Dependent Nuclear Forces and the Damping of Analog States

“…(The energy splitting of the analog from the configuration states is about 4 MeV. 1 ) The values for M aa -and M ac for other nuclei are also of this order of magnitude or are an order of magnitude smaller if all the excess neutrons in the parent belong to the same harmonic-oscillator shell. The configuration-state impurity in intensity is ~10~5, and the spreading width of the analog for the second mechanism is T a i = 80 eV.…”

“…The spreading width of the analog T a | into the more complicated T< states which surround it through its coupling to the configuration states is given by the equation 1,8 "'…”

“…Besides the analog state, a group of T<= (N-Z-l)/2 states can be constructed out of the * Work supported in part by the National Science Foundation. 1 …”

“…The mixing by the charge-dependent Coulomb force has been considered in detail by several authors. 1 However, in addition to the Coulomb force, the nuclear force may have a small charge dependence. The possible importance of a chargedependent nuclear force in the mixing of analog states has been suggested, 2 but no detailed considerations have been given.…”