New users always start with the registration to Belle II Membership System (B2MMS). This generates DESY account which allows access to Belle II collaborative services and tools (B2CS) at DESY.

A KEK account  has to be applied for independently.

There is a Registration and Account FAQ. Don't hesitate to look for your question (no login required).

KEK Registration

The registration with KEK is mandatory for all Belle II users who want to visit KEK, the Belle II detector site (incl. the safety quiz), and need access to computing resources at KEK:

  1. KEK registration:
    • Complete the KEK user registration 
    • Additional instructions for the user registration are here. Note that these instructions are protected by a common user ID and password. This account / password can be found in Organization Belle Collaboration. This also applies to a variety of other links from the main public web page which are located on
    • It says "Nature of Visit" on the first page of the registration and makes it sound like this is about visiting in person, but you can simply ignore this and fill the fields as described in the additional instructions.
    • Undergraduates must first submit an additional form to the Belle secretary before completing the KEK user registration. This is described here (same password as described above)
    • Support:
    • IMPORTANT : You need to renew the KEK user registration for every fiscal year. Usually the Belle secretary announces this annual renewal in later February or early March. Please finish it well before the start of the next fiscal year in April.
  2. KEK computing account (if needed): After you receive confirmation of your user registration, you can apply for access to the KEK computing system (KEKCC access server, KEKCC work server, VPN, KDS).
    • Application should be done through ccportal (you need to create a new account to log in there); more information is in the user guide provided by KEK computing center
    • Some fields you might need:
      • KEK contact person's email address (in the form in CCportal, it is indicated as "Introducer"): 
      • Category manager's email address (for KDS registration):
      • KDS category: Choose "existing category" and enter 294 for the category
      • KEKCC sub group: b2_belle2
  3. Radiation worker application (if needed): If you plan to work in the Tsukuba hall please register as a radiation worker following these instructions. This can only be done after you have registered as a KEK user. It is definitely worth emailing your form to the radiation control center ( and the Belle secretary (belle-secretary_AT_ at least a week in advance, even though you still need to bring the original with you. The chance of an error in the form is not small. If you require access to the interaction region in Tsukuba Hall, you will need to mention this at the time you get your badge.
  4. Wireless access at KEK (if needed): Before visiting KEK, you should register your laptop and other mobile devices for wireless access.
  5. Audio/Video meetings: Meetings can be attended via SeeVogh/eZuce, TeamSpeak, or Speakapp. Please see these instructions for details on joining the relevant communities. This, and subsequent steps, should be completed after you have received your DESY credentials. 
  6. By-laws: Read the by-laws and adhere to the code of conduct.

You will need to repeat a number of these administrative steps at the start of each Japanese fiscal year, April 1.

Belle II Membership Registration


New users always start with the registration to the Belle II Membership Management System (B2MMS) (This is independent from a KEK account.). It generates credentials (account_name/password NOT email address) to access the Belle II collaborative services (B2CS) hosted at DESY, such as the internal wiki, document serverissue tracker and code repository. The procedure typically takes a workday (CET) and requires action form the institution representative (IR).

Never ever register AGAIN if you have been a Belle II member before! Change your B2MMS record or ask your institution representative to (re-)activate your membership.

Please read the documentation in Belle II User Registration.

Communication tools

Using your DESY credentials learn here which communication tools exist and for which purposes they should be used at Belle II. A beginner friendly introduction to some of them can be found on sphinx.

  1. Mailing lists
  2. Wiki
  3. Notes
  4. DESY INDICO system
  5. eLog
  6. Chat
  7. Issue Tracker
  8. Code Repository

Training & further resources

Further resources to get your started are linked in Training resources & useful links. In particular the online book will be your friend.

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