Each Senator-elect and each employee appointed under subsection (a) of this section is authorized one round trip from the home State of the Senator-elect to Washington, D.C., and return, for the purposes of attending conferences, caucuses, or organizational meetings, or for any other official business connected with the impending Congress. In addition, each Senator-elect and each such employee is authorized per diem for not more than seven days while en route to and from Washington, D.C., and while in Washington, D.C. Such transportation and per diem expenses shall be in the same amounts as are payable to Senators and employees in the office of a Senator under section
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(e) of this title, and shall be paid from the contingent fund of the Senate upon itemized vouchers certified by the Senator-elect concerned and approved by the Secretary of the Senate.