subroutine update_quad_params(vparam, vparam_min)
         use parameters_bmad
         use muon_mod
         implicit none
         real(rp) vparam,vparam_min
         integer i
         do i=1,4
                quad_params%short_quad_field_index(i) =  quad_params_0%short_quad_field_index(i) * (vparam+vparam_min) !all short quads
                quad_params%long_quad_field_index(i) =  quad_params_0%long_quad_field_index(i) * (vparam+vparam_min) !all long quads
                quad_params%short_quad_plate_index(i)%inner =  quad_params_0%short_quad_plate_index(i)%inner * (vparam+vparam_min) !all all plates short quads
                quad_params%short_quad_plate_index(i)%bottom =  quad_params_0%short_quad_plate_index(i)%bottom * (vparam+vparam_min) !all all plates short quads
                quad_params%short_quad_plate_index(i)%outer =  quad_params_0%short_quad_plate_index(i)%outer * (vparam+vparam_min) !all all plates short quads
                quad_params%short_quad_plate_index(i)%top =  quad_params_0%short_quad_plate_index(i)%top * (vparam+vparam_min) !all all plates short quads
                
                quad_params%long_quad_plate_index(i)%inner =  quad_params_0%long_quad_plate_index(i)%inner * (vparam+vparam_min) !all plates long quads
                quad_params%long_quad_plate_index(i)%bottom =  quad_params_0%long_quad_plate_index(i)%bottom * (vparam+vparam_min) !all plates long quads
                quad_params%long_quad_plate_index(i)%outer =  quad_params_0%long_quad_plate_index(i)%outer * (vparam+vparam_min) !all plates long quads
                quad_params%long_quad_plate_index(i)%top =  quad_params_0%long_quad_plate_index(i)%top * (vparam+vparam_min) !all plates long quads
             end do
             return
           end subroutine update_quad_params