An automated experiment apparatus, comprising: a pressure vessel having an opening to define a sample receiving chamber therein, the pressure vessel including a vessel flange having a circular outer shape with a radius about a central axis of the pressure vessel; a sample holding member configured to hold a sample to be accommodated in the sample receiving chamber, the sample holding member including a holder flange having an outer circular shape of the same radius as the vessel flange and configured to make contact with the vessel flange to close the opening; a sensing unit configured to sense at least one of an upper position and a lower position of the sample holding member; a plurality of clamps configured to air-tightly engage the holder flange of the sample holding member and the vessel flange of the pressure vessel wherein each of the plurality of clamps includes a clamp head having a groove configured to engage with the holder flange and the vessel flange, and an actuator connected to the clamp head; a clamping sensor configured to sense a top dead point of the clamp head at which the clamp head is fully pushed out by the actuator to air-tightly engage the holder flange; a gas transfer unit having a gas supplier and a gas discharger connected to the sample holding member and configured to supply or discharge a gas into or from the pressure vessel; a heating unit configured to heat the sample receiving chamber; a pressure sensor configured to measure an internal pressure of the pressure vessel; a user interface configured to receive an input from an user; and a controller configured to receive an input signal from the user interface and a sensing signal from the sensing unit to control in response to the input signal and the sensing signal the actuator of each of the clamps to cause the clamp head to make a transverse movement in a radial direction of the vessel flange to engage the holder flange and the vessel flange, to control in response to a clamping sensor signal received from the clamping sensor the gas transfer unit to supply the gas to the pressure vessel until the internal pressure of the pressure vessel reaches a predetermined reaction pressure as indicated by a pressure sensor signal from the pressure sensor, to control in response to the pressure sensor signal from the pressure sensor the heating unit to heat the sample receiving chamber, and to control the gas transfer unit to discharge the gas from the sample receiving chamber. a pressure vessel having an opening to define a sample receiving chamber therein, the pressure vessel including a vessel flange having a circular outer shape with a radius about a central axis of the pressure vessel; a sample holding member configured to hold a sample to be accommodated in the sample receiving chamber, the sample holding member including a holder flange having an outer circular shape of the same radius as the vessel flange and configured to make contact with the vessel flange to close the opening; a sensing unit configured to sense at least one of an upper position and a lower position of the sample holding member; a plurality of clamps configured to air-tightly engage the holder flange of the sample holding member and the vessel flange of the pressure vessel wherein each of the plurality of clamps includes a clamp head having a groove configured to engage with the holder flange and the vessel flange, and an actuator connected to the clamp head; a clamping sensor configured to sense a top dead point of the clamp head at which the clamp head is fully pushed out by the actuator to air-tightly engage the holder flange; a gas transfer unit having a gas supplier and a gas discharger connected to the sample holding member and configured to supply or discharge a gas into or from the pressure vessel; a heating unit configured to heat the sample receiving chamber; a pressure sensor configured to measure an internal pressure of the pressure vessel; a user interface configured to receive an input from an user; and a controller configured to receive an input signal from the user interface and a sensing signal from the sensing unit to control in response to the input signal and the sensing signal the actuator of each of the clamps to cause the clamp head to make a transverse movement in a radial direction of the vessel flange to engage the holder flange and the vessel flange, to control in response to a clamping sensor signal received from the clamping sensor the gas transfer unit to supply the gas to the pressure vessel until the internal pressure of the pressure vessel reaches a predetermined reaction pressure as indicated by a pressure sensor signal from the pressure sensor, to control in response to the pressure sensor signal from the pressure sensor the heating unit to heat the sample receiving chamber, and to control the gas transfer unit to discharge the gas from the sample receiving chamber.