A new method to correct the emulsion deformation, mainly produced in the development process, is developed to recover the high accuracy of nuclear emulsion as a tracking device. The method is based on a precise photomask and a careful treatment of the emulsion films. A position measurement accuracy of 0.6 {\mu}m is obtained over an area of 5 cm x 7 cm. The method allows to measure positions of track segments with submicron accuracy in an ECC brick with as few as 10 reference tracks for alignment. Such a performance can be important for hybrid emulsion experiments at underground laboratories where only a small number of reference tracks for alignment are available.
@article{arxiv.1210.1344,
title = {A new method to correct deformations in emulsion using a precise photomask},
author = {M. Kimura and H. Ishida and H. Shibuya and S. Ogawa and T. Matsuo and C. Fukushima and G. Takahashi and K. Kuge and Y. Sato and I. Tezuka and S. Mikado},
journal= {arXiv preprint arXiv:1210.1344},
year = {2015}
}