Update on the ilc dr alternative lattice design

In order to reduce the cost for ILC damping rings, an alternative lattice which is different from the baseline configuration design has been designed previously with modified FODO arc cells, and the total quadrupole and sextupole number has been reduced largely, compared with the baseline design. At the same time, to decrease the total cost involved in constructing access shafts needed to supply power, cryogenics etc. for the wigglers and other systems, the number of wiggler sections is decreased from 8 to 4, and further to 2. However, the momentum compaction of this lattice can not be tuned freely. In this paper, a new ILC damping ring lattice design with a variable momentum compaction will be presented, followed by the single particle dynamics associated studies.