• S. Hashimoto, S. Miyamoto
  NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
• K. Kawata, Y. Minagawa, T. Shinomoto
  JASRI/SPring-8, Hyogo-ken

The pe­ri­od­ic fluc­tu­a­tions and drifts in the ra­di­a­tion in­ten­si­ty have been ob­served at the New­SUB­ARU syn­chrotron ra­di­a­tion fa­cil­i­ty. To clar­i­fy the cause of this prob­lem we have mea­sured tem­per­a­tures of air, cool­ing water, equip­ments and build­ing with the net­work-dis­tribut­ed data log­ger. And we found that tem­per­a­ture fluc­tu­a­tions in both air in the shield­ed tun­nel and the cool­ing water main­ly af­fect the sta­bil­i­ties of elec­tron beam orbit and op­ti­cal axis. To main­tain a con­stant tem­per­a­ture, the large doors for car­ry­ing equip­ment at the ex­per­i­men­tal hall were cov­ered with in­su­lat­ed cur­tains, and we op­ti­mized PID pa­ram­e­ters of tem­per­a­ture con­trollers for air and water. As re­sults, the pe­ri­od­ic fluc­tu­a­tions al­most dis­ap­peared, but some drifts were still re­mained, which are due to slow vari­a­tions of equip­ment tem­per­a­ture. By re­al­iz­ing the au­to­mat­ic COD cor­rec­tion, the drift in elec­tron beam po­si­tion could be sup­pressed and the fluc­tu­a­tions of ra­di­a­tion in­ten­si­ty ob­served at beam-lines be­came small­er than they used to be. For fur­ther sta­bi­liza­tion, we re­cent­ly in­tro­duced a XBPM up­stream in a beam­line to mea­sure the ver­ti­cal po­si­tion of ra­di­a­tion axis pre­cise­ly.