Target 4 Flight Path 15L

Target 4 Flight Path 15L (Chi-Nu)

Target 4 Flight Path 15L (4FP15L) has a neutron beam at an angle of 15-degrees to the incident proton beam from the spallation source. It is unique among the WNR flight paths in that it has two experimental locations available at distances of 22 and 90 m from the spallation target. The rectangular shutter has variable openings in x- and y- dimensions and therefore allows the neutron flux intensity to be varied according to experimental requirements. The shape of the beam spot can also be changed by inserting collimator inserts in the neutron beam tube. This flight path is primarily used for the Chi-Nu experiments at 22 m and neutron detector development and calibration at 90 m. In order to minimize room return of neutrons to detectors near the target position, the 22 m cave has a “false-floor,” such that the concrete floor is 2 m below the false floor, and the cave walls are also well removed from the target position. The 90 m cave allows improved neutron energy resolution for higher neutron energies, due to its long flightpath.

The Chi-Nu Detector Array