A detailed comparison between the observed and expected loss of alpha-like MeV fusion products in TFTR is presented. The D-D fusion products (mainly the 1 MeV triton) were measured with an 2-D imaging scintillation detector. The expected first-orbit loss was calculated with a simple Lorentz orbit code. In almost all cases the measured loss was consistent with the expected first-orbit loss model. Exceptions are noted for small major radius plasmas and during strong MHD activity.

Fast ion losses resulting from MHD modes at the Alfv6n frequency, such as the TAE, have been observed in TFTFt. The modes have been driven both by neutral beam ions, at low BT, and by H-minority ICRF t a i l ions at higher BT. The measurements indicate that the loss rate varies linearly with the mode amplitude, and that the fast ion losses during the mode activity can be significant, e.g. up to 10% of the input power is lost in the worst case.

The TFTR multichannel neutron collimator provides time-resolved neutron emission profiles from ten vertical chords spaced in major radius across the vacuum vessel. An in situ calibration of the system has been made using a 120 mCi 252Cf source scanned inside the vacuum vessel. A mapping of the effective neutron acceptance aperture was performed and showed reasonable agreement with the optical predictions testifying to the effectiveness of the interstitial shielding material. Crosstalk between channels was evaluated and found to be negligible. Periodic renormalization of the system has shown a standard deviation among the sensitivities of only 2.0% over the first seven months of operation.