Vessel for a radiation source

An EUV radiation source comprising:

• a vessel configured to house an EUV radiation source system, the vessel comprising:
• a first opening configured to allow a user to access an interior of the vessel;
• a first access member configured to allow or prevent access to the interior of the vessel through the first opening;
• a second opening configured to allow the user to access the interior of the vessel, wherein the second opening is configured in the first access member;
• and
• a second access member located on the first access member and configured to allow or prevent access to the interior of the vessel through the second opening.

A lithographic system comprising:

• an EUV radiation source comprising:
• a vessel configured to house an EUV radiation source system, the vessel comprising:
• a first opening configured to allow a user to access an interior of the vessel;
• a first access member configured to allow or prevent access to the interior of the vessel through the first opening;
• a second opening configured to allow the user to access the interior of the vessel, wherein the second opening is configured in the first access member;
• and
• a second access member located on the first access member and configured to allow or prevent access to the interior of the vessel through the second opening;
• and
• a lithographic apparatus.

A method comprising:

• exchanging at least a first component of an EUV radiation source, the radiation source comprising a vessel for housing an EUV radiation source system, the vessel comprising:
• a first opening for accessing an interior of the vessel;
• a first access member configured to allow or prevent access to the interior of the vessel through the first opening;
• a second opening for accessing the interior of the vessel, wherein the second opening is configured in the first access member;
• and
• a second access member located on the first access member and configured to allow or prevent access to the interior of the vessel through the second opening;
• operating the first access member to allow access to the interior of the vessel through the first opening;
• removing at least the first component to be exchanged;
• installing at least another first component to be used;
• and
• operating the first access member to prevent access to the interior of the vessel through the first opening.

A method comprising:

• exchanging a second component of an EUV radiation source, the radiation source comprising a vessel for housing an EUV radiation source system, the vessel comprising:
• a first opening for accessing an interior of the vessel;
• a first access member configured to allow or prevent access to the interior of the vessel through the first opening;
• a second opening for accessing the interior of the vessel, wherein the second opening is configured in the first access member;
• and
• a second access member located on the first access member and configured to allow or prevent access to the interior of the vessel through the second opening;
• operating the second access member to allow access to the interior of the vessel through the second opening;
• removing the second component to be exchanged;
• installing another second component to be used;
• and
• operating the second access member to prevent access to the interior of the vessel through the second opening.