The ITS10 organizing committee looks forward to welcoming international attendees to our 2023 Symposium in Anaheim California, USA. To travel to the United States and attend the symposium, you may need a US entry visa. Such visas are administered though the US Department of State. The information we have posted here is provided to help our international attendees with the basic requirements concerning nonimmigrant B-1/B-2 visas. The American Physical Society (APS) has an excellent web site for this same purpose and we have borrowed much of the content shown here from their site. In certain cases where an official Invitation letter is needed for the purposes of a visa application, the ITS10 can issue such a letter to qualified attendees through a process described below. However, please note that the ITS10, MSC and NIST are not involved in any visa process, and please note that regulations may change without much notice. The best resources for accurate information about the visa application process are US government websites such as those listed below.
ITS10 or any of its officials cannot intervene with US Embassies or consulates abroad or with the US State Department on behalf of any ITS10 symposium attendee.

Visa Application Process for Non-US Citizens/Residents

Visa Types

Generally, non-US citizens/residents must obtain a nonimmigrant B-1/B-2 visa to enter the United States for a temporary visit.


Visa Waiver Program

Under the Visa Waiver Program (VWP), citizens of certain countries may travel to the United States for stays of ninety days or less without a visa. Anyone traveling under VWP must apply for authorization through the Electronic System for Travel Authorization (ESTA). The current list of VWP Designated Countries is shown on the following US State Department page:

The starting point for new individual applications under the VWP is found here:


Register for ITS10 and request a Visa Invitation Letter

If you are not eligible to travel under the Visa Waiver Program, your US consulate office may require that an official Invitation Letter be issued to you from the ITS10 as part of your visa application package. Register for ITS10 here to start the process. Once your registration is complete, you will have an opportunity to request an ITS10 Visa Invitation Letter.

If you are an author of an accepted abstract for ITS10, but you are unable to register for the Symposium until some later time, you may also request an ITS10 Visa Invitation Letter which is tied to your accepted abstract. This option is intended for those individuals for whom their government or employer requires them to wait until the “last minute” before authorization to travel and or register. In this case the author will have an opportunity to make the request through their EDAS account.

Set Up Your Visa Interview

If you are not eligible to travel under the Visa Waiver Program, you may be required to appear at a US embassy or consulate for an in-person interview prior to visa approval. There may be long waits to schedule an interview, so start the application process as early as possible.


What to Bring to Your Visa Interview

  • A valid passport.
    Note: Consular Officers do not need to retain your passport.
  • The online nonimmigrant visa application (Form DS-160) confirmation page.
  • Specific and detailed explanations related to your purpose for travel, including your official ITS10 Invitation Letter.
  • Complete travel itineraries and schedules if appropriate.
  • Proof of the established relationship with the ITS10, either a copy of your MSC/ITS10 Symposium registration or a copy of your abstract acceptance email from the ITS10 Program Committee.
  • An explanation of how your visit will be funded.
  • Your professional resume or curriculum vitae.
  • Other information as directed by a consular officer.


Visa Interview Appointment Wait Times

The US Department of State’s Bureau of Consular Affairs provides wait times for visa interview appointments for every US Consulate worldwide.


Administrative Processing

Some applications require additional “administrative processing” and this adds several weeks to the application process. Applicants involved in scientific fields are often subjected to administrative processing and should apply for visas as early as possible, preferably three to four months in advance. Bring your professional credentials, ITS10 documentation and letter of invitation to the visa interview to help facilitate any additional processing.

Visa Delays

The APS has provided information on what to do if your visa application is delayed excessively,

Entering the United States

The APS also has provided a useful collection of information concerning policies and procedures for entering the US.


US Government Sites