A systematic survey was conducted in Laohegou Nature Reserve in Sichuan Province from mid-April to late October, 2013 (13 repeats altogether, about 15 days between repeats). Supplementary surveys were carried out in 2014 and 2015. 252 species of butterfly were found in total belonging to 12 families and 117 genera, in which the richness of Nymphalidae is the highest (33.3%). During the systematic survey in 2013, there were 235 species found, and 17 species were newly recorded in 2014 and 2015, indicating that almost complete information may be obtained based on our survey protocol. There were 3 species assessed globally as “least concern” by IUCN Red List, and 5 species protected by Chinese law. The proportion of Palearctic, Oriental, and Palearctic-Oriental species was 3.3%, 32.9%, and 63.8%, respectively. Taking the butterfly fauna composition of other districts into account, Qinling and Minshan mountains were found to serve as geographical barrier to the dispersal of Palearctic and Oriental species. The butterfly richness was the highest from June to September. Butterfly species richness was unimodal in general with elevation rising. The highest was in 1500–1600 m, and there was a minor peak in 1000–1100 m, in which the transect lied in a village near the boundary of the reserve, indicating that moderate interference by human activity was conducive to the conservation of butterfly diversity. This work provides an optimized protocol for butterfly monitoring survey.

In order to achieve high accuracy IBA (ion beam analysis), the calculation error of solid angle were discussed meticulously. The accuracies of face to point solid angle and approximate solid angle were calculated, based on face to face solid angle which contained area of beam spot. Based on 4.5 MV electrostatic accelerator ion beam target chamber of Peking University, solid angle influenced by distributions of cross-section and beam intensity was determined. A geometry-condition estimation for accuracy of approximate solid angle better than 1% was given and verified by two examples. For fatherly achievement of high-accuracy solid angle, accurate machining such as laser processing is required.