This proposal was submitted on MERLIN (RB1010206) and beam time was allocated on MARI. We have carried out low energy measurements on MARI and found a clear evidence of the spin gap in CeRu2Al10 (gap=8meV) and CeOs2Al10 (gap=11meV). We have published two papers in PRB [10-11] and another paper has been submitted to PRB [12]. However, our attempt to study the spin gap in the Kondo insulator CeFe2Al10 (Ei=25 and 100meV) was not successful on MARI. Further, we have seen an evidence of broad high energy CEF excitations between 40 and 60meV in CeRu2Al10 and CeOs2Al10. However, due to low flux on MARI and weak magnetic signal gave poor quality of the data that did not allow us to do any quantitative analysis based on CEF model. The information on CEF wave functions is important to test various proposed theoretical models. Here we request beam time on MERLIN /MARI to complete the study.