Test Experiment

A series of test experiments were conducted for checking the beam optics for the INGA beamline. A quartz crystal was used to view the beam profile at the target position. It was found that the magnetic fields in the last quadrupole triplet had to be reduced by about 30% in order to shift the focus fromthe last beam profile monitor (BPM) in the beamline to the target position, 2 m downstream from the BPM.

The position of a removable collimator in the beamline has been adjusted for centering the beam on target location. All the signal cables, electronics and data acquisition system were checked out during the test measurements. For multi-crate readout of ∼ 120 parameters, the total dead time including signal processing and readout time per event was measured to be 75 μs. Typical coincidence count rates were ∼ 12 kcs γ-γ doubles and 3-4 kcs γ-γ-γ triples for a total singles γ rate of 60-80 kcs.