Performance of Integration Cube type (Fig.22(b)) has been investigated as well. Position dependences is studied in horizontal direction () at y = 0. Photoelectron yield of each PMT and sum of two PMT's are plotted in Fig.31. Unlike the Belle type, Integration Cube type gives very flat distribution. With Belle type, decrease by a factor of 5 is seen in propagation of 10 cm, but with Integration Cube type, decrease of only 10 % is seen.1 Total yield of photoelectron (sum of two PMT's) at the center is about 19, which is about 20 % smaller than that of Belle type.
Uniform photoelectron yields are demonstrated in Fig.32. Sum of two PMT's are plotted as a function of for [cm]. The photoelectron yields are found to be stable within 10%.
For further study of this type, Integration Cube types with other geometries have been studied. In fig.33, effects of integration cube volume are studied. Depth of Integration Cube is reduced from 12 cm (solid circle) to 6 cm (solid square). By reducing the integration volume by a factor of 2, photoelectron yields increases from 19 to 22 while slight position dependence is appeard.
When the width of the counter is doubled, namely changing from to , while keeping the same thickness of aerogel, the photoelectron yield decreses from 19 to 10. Thus, there is strong correlation between the volume or surface area of Integration Cube and photon yields.
In the stacking configuration of Integration Cube type counters (Fig.16), every other cells are stacked in reverse direction in order to eliminate dead space and having the aerogel at the same radius. In this configuration, some particles enter in reverse direction. Effects of direction of particle injection have been studied. Integration Cube type counter has been rotated by 90, 180 and 270 degrees and photoelectron yields are compared. Path length of particle trajectory along the aerogel has been kept the same for comparison. As listed in Table. 2, photoelectron yield decrease by when particles enter from the back to front. This rather small difference suggests that most of photons in the integration cube do not have directionality already, which is again consistent with the diffusive optical property of the aerogel.