Patent Number: 
Section: claims

1. A beam intensity converting film comprisingone or more graphite films placed such that a surface thereof intersects a beam axis of a charged particle beam,wherein the one or more graphite films have an opening that allows passage of the charged particle beam,wherein the one or more graphite films each have a thickness of 1 μm or greater,wherein, in the one or more graphite films, a thermal conductivity in a surface direction is equal to or greater than 20 times a thermal conductivity in a thickness direction,wherein, in the one or more graphite films, an electric conductivity in a surface direction is equal to or greater than 100 times an electric conductivity in a thickness direction,wherein, in the one or more graphite films, the electric conductivity in the surface direction is 18000 S/cm or greater, andwherein the one or more graphite films have an open area ratio of 10 to 50%, wherein the open area ratio is a ratio of an area of the opening to an area of a surface of the one or more graphite films. 2. The beam intensity converting film according to claim 1, wherein, in each of the one or more graphite films, the thermal conductivity in the surface direction is 1000 W/(m·K) or greater. 3. The beam intensity converting film according to claim 2, wherein, in each of the one or more graphite films, the thermal conductivity in the surface direction is 1600 W/(m·K) or greater. 4. The beam intensity converting film according to claim 1, wherein the one or more graphite films have a density of 1.70 g/cm3 or greater and 2.26 g/cm3 or less. 5. The beam intensity converting film according to claim 4, wherein the one or more graphite films have a density of 2.00 g/cm3 or greater and 2.26 g/cm3 or less. 6. The beam intensity converting film according to claim 1, wherein the one or more graphite films are two or more graphite films, and the beam intensity converting film includes a stack of the two or more graphite films. 7. The beam intensity converting film according to claim 1, wherein the number of times each of the one or more graphite films is folded in an MIT folding endurance test is 1000 or more. 8. A method of producing a beam intensity converting film including one or more graphite films, the method comprisinga step of preparing the one or more graphite films by heat treating one or more polymeric films in a furnace,wherein the one or more graphite films have an opening that allows passage of a charged particle beam;wherein the one or more graphite films each have a thickness of 1 μm or greater,wherein, in the one or more graphite films, a thermal conductivity in a surface direction is equal to or greater than 20 times a thermal conductivity in a thickness direction,wherein, in the one or more graphite films, an electric conductivity in a surface direction is equal to or greater than 100 times an electric conductivity in a thickness direction,wherein, in the one or more graphite films, the electric conductivity in the surface direction is 18000 S/cm or greater, andwherein the one or more graphite films have an open area ratio of 10 to 50%, wherein the open area ratio is a ratio of an area of the opening to an area of a surface of the one or more graphite films.