Development of cold interferometer for pulsed source

M. Kitaguchi(A), M. Hino(A), H. Funahashi(B), Y. Seki(C), K. Taketani(D), and H.M.Shimizu(D) (A)KURRI, (B)Kyoto Univ., (C)RIKEN, (D)KEK

Neutron interferometry is a powerful tech- mirror, at cold neutron beam line MINE2 at nique for studying fundamental physics. A the JRR-3 reactor in JAEA. large dimensional interferometer for long Polarization interferometer was used for wavelength has the advantage to the performed experiments. One of the two increase the sensitivity to small interac- mirrors on the BSE is a polarizing mirror tions. Such a kind of interferometer was re- and each path corresponds to a spin com- alized by using multilayer mirrors. Multi- ponent. We have installed the polarization layer mirror is suitable for Bragg reflection devices into cold neutron beam line BL05 of cold neutrons. We demonstrated Jamin- low divergence branch in MLF at J-PARC. type interferometer for cold neutrons using We have observed TOF interference fringes beam splitting etalons (BSEs), which en- for pulsed neutrons by using the devices ables us to align the four independent mir- which synchronized with neutron produc- rors within required precision [1]. The BSE tion, without BSEs. The experiments using contains two parallel mirrors. A couple BSEs with supermirrors are started now. of the BSEs in the Jamin-type interferome- We are also planning the experiments us- ter separates and recombines the two paths ing the interferometer as one of fundamen- spatially. A is one of tal physics investigations at J-PARC. the multilayer with continuous lattice con- stants, which reflects the wide range of [1] M. Kitaguchi, et. al., Phys. Rev A 67 the wavelength of neutrons. The BSEs with (2003) 033609. neutron supermirrors enable us to arrange Jamin-type geometry of the interferome- ter for white neutrons. The interferometer can be applied to pulsed neutrons by us- ing the BSEs with supermirrors. Such inter- ferometer increase the neutron counts for high precision measurements, for example, Aharonov-Casher effect. Wevelength de- pendence of the interaction in the interfer- ometer also can be measured by the time of flight detection for pulsed neutrons. We have already performed test experi- ments using polychromatic mirrors with two different lattice constants. We fabri- Fig. 1. TOF interference fringes at BL05 in MLF at cated two polychromatic mirrors with in- J-PARC termediate gap layer on the top of Si sub- strate continuously. This device enabled us to provide two separated paths of the Jamin-type interferometer for two wave- length of neutrons. We observed clear in- terference fringes at the two different inci- dent angles, which were corresponding to the two multilayers in the polychromatic

Activity Report on Research: Experimental Reports 17 (2010) Report Number: 1125