NeXus International Advisory Committee
- Aaron Brewster, Lawrence Berkeley Laboratory, USA (Chair)
- Sandor Brockhauser, Center for Materials Science Data (HU Berlin), Germany (Executive Secretary)
- Peter Chang, Diamond Light Source, UK (Documentation Release Manager)
- Benjamin Watts, Swiss Light Source, Switzerland
- Mark Könnecke, PSI, Switzerland
- Herbert Bernstein, CIF (non-facility member)
- Thomas Caswell, Brookhaven National Laboratory/NSLS-II, USA
- Bjørn Clausen, Los Alamos National Laboratory, USA
- Heike Görzig, Helmholtz Zentrum Berlin, Germany
- Pete Jemian, Advanced Photon Source, USA
- Raymond Osborn, Argonne National Laboratory, USA (non-facility member)
- Wout de Nolf, European Synchrotron Radiation Facility, France
- Takahiro Matsumoto, Spring8, Japan
- Balázs Bagó, the Extreme Light Infrastructure, Czech Republic, Hungary and Romania
- Russ Berg, Canadian Light Source, Canada
- Majid Ounsy, Synchrotron Soleil, France
- Chen Zhang, Oak Ridge National Laboratory (SNS/HFIR), USA
- Luca Geliso, European XFEL, Germany
- Paul Millar, DESY, Germany
See the page with the expiration dates for when the current terms of the various members end and we require a new facility endorsement and vote (see below).
You may contact the NIAC by sending an email to
Terms of Reference
The purpose of the NeXus International Advisory Committee is to
supervise the development and maintenance of the NeXus common data
format for neutron, x-ray, and muon science. This purpose includes, but
is not limited to, the following activities.
- To establish policies concerning the definition, use, and promotion
of the NeXus format.
- To ensure that the specification of the NeXus format is sufficiently
complete and clear for its use in the exchange and archival of
neutron, x-ray, and muon data.
- To receive and examine all proposed amendments and extensions to the
NeXus format. In particular, to ratify proposed application
definitions and base classes, to ensure that the data structures
conform to the basic NeXus specification, and to ensure that the
definitions of data items are clear and unambiguous and conform to
accepted scientific usage.
- To ensure that documentation of the NeXus format is sufficient,
current, and available to potential users both on the internet and
in other forms.
- To coordinate with the developers of the NeXus Application
Programming Interface to ensure that it supports the use of the
NeXus format in the neutron, x-ray, and muon communities, and to
promote other software development that will benefit users of the
- To coordinate with other organizations that maintain and develop
related data formats to ensure maximum compatibility.
The committee will meet at least once every calendar year according to
the following plan:
- In years coinciding with the NOBUGS series of conferences (once
every two years), members of the entire NIAC will meet as a
satellite meeting to NOBUGS, along with interested members of the
- In intervening years, the executive officers of the NIAC will
attend, along with interested members of the NIAC. This is intended
to be a working meeting with a small group.
The NeXus International Advisory Committee will seek balanced
representation of the international community. It will consist of at
most one voting representative from each major neutron, synchrotron
x-ray, and muon facility. Membership would normally be for a three year
renewable term. Members will be nominated by each facility through the
facility director and approved by the existing committee. Each member
can appoint a substitute to attend a particular meeting.
The committee reserves the right to appoint additional members for a
limited period to ensure balanced representation.
Accountability: The NeXus International Advisory Committee will ensure that their decisions are reported both on the NeXus web site and on the NeXus mailing list. Committee business will be conducted either through a mailing list, to which non-committee members can subscribe and whose archive will be available on the web, or through meetings, which will be advertised on the NeXus mailing list and which non-committee members may attend.
The NeXus International Advisory Committee will have the following
- Chair to oversee committee deliberations
- Executive Secretary to coordinate meetings and online debates. The
person that holds the position does not need to be an existing
member of the NIAC, and does not vote unless he/she is a regular
- Technical Manager with the responsibility to oversee the NeXus API.
The tasks of the manager are to coordinate tests, manage and
announce releases, and promote code from the contributed directory
to the regular release build. The person that holds the position
does not need to be an existing member of the NIAC, and does not
vote unless he/she is a regular member.
- Definition Release Manager with the responsibility to oversee the
release of NeXus definitions and documentation. The person that
holds the position does not need to be an existing member of the
NIAC, and does not vote unless he/she is a regular member.
All of these officers will be elected for a two year term. The incumbent
chair and executive secretary are limited to two consecutive terms.
Voting: Only members of the NeXus International Advisory Committee will
be able to vote on specific proposals that come under the remit of the
committee. However, all debates will be conducted publicly and
non-committee members are both allowed and encouraged to participate.
Topics voted on at the biennial NIAC meetings will require a simple majority unless specifically
challenged by a committee member. In the event of a challenge, the issue
will be presented to the NeXus mailing list inviting comments for a
period of one month. At the end of this period, the challenge can be
overruled by a two thirds majority.
Voting outside of the biennial NIAC meetings can take two forms.
Firstly, memberships can be approved by email ballot. All other issues
require a teleconference for interactive discussion that is attended by
at least 2/3 of the NIAC. Votes may be cast at the teleconference, as well
as during the following week in order to allow NIAC members not attending
the teleconference to add their vote to the tally. The opening of the
voting period must be advertised through the NIAC mailing list. At the
close of the 1-week voting period, NIAC members not responding are counted
as abstained and the NIAC decision follows the voting category (usually
“for” and “against”) with the highest number of valid votes.
The constitution can only be changed by a two thirds majority of the
Special Interest Groups: The NeXus International Advisory Committee will appoint editors to be in charge of particular groups that wish to specify instrument definitions or develop specialized uses of the NeXus format. The groups will establish their own mode of operation, but will be expected to consult widely with the community relevant to their work, and to refer back to the NeXus International Advisory Committee any matters that involve a change in the current NeXus specification. Specific proposals produced by these groups will be presented to the NeXus International Advisory Committee for comment and formal ratification.
- Code Camp June 2023: Code Camp, (virtual)
- NIAC 2022 NIAC Meeting, (hybrid)
hosted by the Paul Scherrer Institute, Switzerland, September 2022
- Code Camp 2022: Code Camp, (virtual)
- Spring 2022 Virtual NIAC special NIAC Meeting, (virtual)
- Code Camp 2020-2 NeXus Code Camp 2020-2, (virtual)
hosted by the European XFEL, Hamburg, Germany, October 2020.
- NIAC 2020 NIAC Meeting, (virtual)
hosted by the European XFEL, Hamburg, Germany, October 2020.
- Code Camp 2020: Code camp,
hosted by APS, Chicago, USA, January 2020
- NIAC 2018: NIAC Meeting,
hosted by NSLS-II, Brookhaven, USA, October 2018
- Code Camp 2017: NeXus Code Camp,
hosted by Diamond Light Source, UK, October 2017
- NIAC 2016 NeXus Code Camp and NIAC Meeting,
hosted by ESS, Copenhagen, Denmark, October 2016
- Code Camp 2015 NeXus Code Camp, hosted
by DESY, Hamburg, Germany, November 2015 (no minutes)
- NIAC 2014 NeXus Code Camp and NIAC Meeting,
hosted by APS, Chicago, USA, December 2014
- NIAC 2012 NeXus Code Camp and NIAC Meeting,
hosted by ISIS and Diamond at RAL, Oxfordshire, UK, September 2012
- NIAC 2011 NeXus Code Camp and NIAC
Meeting, APS, October 2011
- NIAC 2010 NeXus Code Camp and NIAC Meeting,
ORNL, October 2010
- October 16-18 2009 NeXus Code Camp, hosted by
APS, Chicago (Evanston, Illinois) (no minutes)
- October 30-31, 2008 at ANSTO, Australia
- September 24-26, 2007 at HMI, Berlin, Germany
(online and pdf
- October 5-6, 2006 at LBL, Berkeley, CA,
- February 1-3, 2006 at ILL, Grenoble,
- April 26-28, 2005 at Bishops Lodge in Sante Fe, NM, USA
- October 21-22, 2004 at PSI, Villigen, Switzerland
- September 8-10, 2003 at Pasadena, CA, USA
NIAC Decisions sorted by Topic
This is a collection of past NIAC decisions sorted by topic. This serves
mainly as a reference for NIAC members, hence the recording is rather
terse and not meant for consumption on it’s own.
Action Items for members of the NIAC that
are not associated to one of the repositories.
The former NeXus Technical sub-committee
that used to host regular teleconference meetings
has been retired.
In the interest of being inclusive and approachable
the sessions are now open to all interested parties.
See the Teleconferences page for agendas, minutes, and how to join.