Alain Blondel

1
Track fit conventions for HARP
The fit outputs five parameters w 1/R the
signed curvature, convention a positive
particle in a positive B field will have a
positive cuvature. (turns clockwise) d0 the
signed impact parameter. Convention a
positive impact parameter means that the origin
of axes is inside the track circle. j0 the
azimuthal angle of the track vector at the point
of closest approach (the oriented tangent to the
circle) z0 z- coordinate of the point of
closest approach of the track to the origin tan
l , where l is the dip-angle of the track
(latitude, not polar angle)
y
uj
ur
yo
j0
b0
a0
X
C
dy
x
M0
M
Case where Rgt0, d0gt0 .
N.B. The triedron ( ur, uj,Oz) is always direct
according to Lorentz law. d0 and R are the
coordinates of O and C on the axis M0ur N.B.B.
The choice of sign of R assumes a certain
direction of motion, parallel to uj ! dy will
decrease with time if Rgt0. One could describe the
same trajectory with the consistent change
R-gt -R, j0 ? j0 p , tan l ? - tan l
which would describe a particle of the other
charge advancing in the other direction
2
The Uni-GVA ESA contract -- the facts --
In March, we were approached by S. Giani who
pointed out the existence of calls for tender
from ESA.  This announcement is targeted at the
European academia, institutes and industry for
the development of space specific modules and
algorithms in the Geant4 particle transport
toolkit and for space specific analysis using
these. The activities shall be compatible with
the aims of ESA Intended invitation to tender
01.160.37 -- Energetic particle shielding and
interactions software. The emphasis is on
applications and developments relevant for future
ESA science missions  What ESA wants is to be
able to design electronics and shielding against
dammage from cosmic radiation. For this we felt
that UNI-GVA was well placed by the existence of
the following groups -- the neutrino factory
RD group (A.B) involved in HARP and in the
studies of neutrino factory components relevant
here are 1) the understanding of hadronic
interactions problems from HARP experience 2)
expertise in material dammage from Horn studies
S. Gilardoni -- the AMS group (Prof. Martin
Pohl) who has experience in semiconductors in
space through the AMS-1 mission, and carried out
many measurements on single event effects at
e.g. GSI, using heavy ion beams. Such a
synergy of competences seemed well fit for the
purpose and submitted a proposal with
titles Tender 1. Implementation of Hadronic
cross-sections in GEANT4  Tender 2. Cosmic ray
fluxes and single event effects
3

• this proposal stated
• The following objectives of the statement of work
  can be covered
•  
• HARP and Neutrino Factory RD group
• Hadron interactions for single event effects and
  astronaut hazard analysis
• Validation of code through comparison with
  experimental data and other codes
• Implemetation and improvement of general
  capabilities, etc
• AMS group
• Hadron interactions for single event effects and
  astronaut hazard analysis
• Detailed research on detector radiation
  background
• Other developments and applications relevant to
  enhanced utilization of GEANT4 in space
  applications
• the bid was for two contracts of 40k each
• from which we could support one experienced
  researcher (V. Grichine from Lebedev)
• and a student (one from each group) for one year.
  

4
as of April 2002

•  
• 2.3  Study plan
•  
• At this moment we can see the following plan of
  work
•  
• Study of the existing code, experimental data and
  knowledge of relevant processes. This study will
  fix the kind of code to be written (new classes,
  modifications to existing ones, inclusion of data
  structures, etc) Compilation of existing data vs
  those collected in AMS and in HARP.
• Description of interactions of primary particles
  in the energy range of 1-10 GeV per nucleon. The
  data of the HARP experiment on various materials
  should become available already at the end of
  2002 and provide valuable input.
• Improvements of the description of the primary
  cosmic ray flux for various nuclei including data
  from the first AMS flight.
• Creation of modules describing single event
  effects in semiconductors using data collected in
  space and at GSI. Implementation of heavy ion
  interactions in GEANT4.
• Benchmark the improvements achieved using the
  additional modules. Validation of the code,
  mainly with experimental data, and the proposal
  of new experiments in case of need in order to
  complete the project.
• 6. (if time permits) Creation of a procedure by
  which new data can be included in the description
  of the processes in a simple way.

nb in hindsight, the date for HARP data
available (end 2002) was obviously
too optimistic. remember that at the time there
was talk of a first publication in october! the
proposal was submitted on 2 May 2002.
5
we got an answer on 9 october 2002 from a
contractor who had a number of questions
1) HARP data right we are a bit concerned on the
data right issue. Will it be possible for you to
confirm that your group do have the right of
access to HARP data and the HARP collaboration
has granted you the right to use the data in a
Geant4 implemetation? or just inform us that HARP
data is in the public domain if it is the case.
3) HARP data are in the range of 1-10 GeV, but
for space applications we would like to see the
data compilation activity to include
cross-sections data down to 100 MeV. This means
exploring data from other sources rather than
HARP.
4) There is not enough information in the
proposal on the actual work you are going to
perform, and we are not too clear on how a c-s
based final states generator can be implemented
for general applications. We would like ask
you to consult Hans-Peter Wellisch
(Hans-Peter.Wellisch_at_cern.ch) who is the
hadronic physics category coordinator in the
Geant4 collaboration to work out a better defined
study plan and work package. We have already
informed Hans-Peter on this and he is happy to go
through the issues with you.
the first question clearly indicates that the
person was not accustomed with the uses of the
HEP community! we went on to discuss with
Hans-Peterand agreed to work in the framework of
his hdronic group.
6

• our answer
• HARP data right we are a bit concerned on the
  data right issue. Will it be possible for you
• to confirm that your group do have the right of
  access to HARP data and the HARP collaboration
• has granted you the right to use the data in a
  Geant4 implemetation? or just inform us that HARP
  
• data is in the public domain if it is the case.
• All persons concerned are members of the HARP
  collaboration. We therefore have access to the
• HARP data. This gives us good knowledge and
  understanding of the format of the data and
• of what they consist.
• I should like to clarify one point however as
  written in our proposal, 'HARP data, once
  available,
• will provide valuable input'. The question
  arises what does 'available' mean? The
• HARP experiment has taken data since mid 2001
  until mid october 2002. These 'raw data' need
• to be calibrated and assembled before one could
  extract reliable physics quantities
  (cross-sections
• and multiplicities for instance) that could be
  useful for other physicists or other
  applications. This
• analysis process will take a certain amount of
  time and will lead to publication. Some basic
  results
• maybe published already toward the end of this
  year, but it is likely that a more complete
  publication
• of results will not take place until 2003 or even
  later.

7
the grant for ONE contract was awarded on 11
November 2002. this means that we will be able
to support one person 40 for one year. (or 80
for 6 months). this is not much but we hope to
do useful work given that 1. GEANT is a PUBLIC
SOURCE CODE 2. the data used should be
published I believe that what we do is perfectly
OK both for ESA and for HARP (we made no
promises that could be detrimental to HARP)
FURTHERMORE we certainly would hope that this
will be useful for HARP! HOW? I think there is
time to discuss since the contract only starts in
February or March 2003 In general I believe that
what we have done is highly positive) and
beneficial to the collaboration i) it can be
providing help in the much needed area of the
HARP monte-carlo, and ii) the task of
understanding how to implement the data in GEANT4
will prompt us to understand how to publish, and
vice versa the task of implemention will help us
presenting the published data in the most useful
way.
) humoristic reference to highly questionable
-- not to be taken with such emphasis!
8

• Rules on HARP data (as of coll. board 10.6.2002)
• 1. HARP data are common property of the HARP
  Collaboration.
• The scientific integrity of the results to be
  made public is the responsibility of the whole
  collaboration. Therefore, results must be
  approved at a collaboration meeting (or
  equivalently representative meeting). Preprints
  and articles in refereed journals require prior
  agreement by the Collaboration Board
  (represented, in urgent cases only, by the
  spokesperson).
• 3. The HARP Collaboration has four
  associate members'. These are the BARTOL group,
  and groups of a small number of individuals from
  the GEANT4, K2K and MiniBooNE collaborations.
  Associate members have unrestricted access to
  HARP data under rules 1 and 2 above.
• HARP publication policy
• 1. Reports and/or publications of subsystem
  design and/or performance can be made with a
  restricted number of authors but need prior
  agreement by the Collaboration Board
  (represented, in urgent cases only, by the
  spokesperson).
• 2. Reports at conferences can be made by a
  single author, with the annex representing the
  HARP Collaboration'. The presentation should be
  authorized by the speakers bureau'.
• 3. All other reports and/or publications
  will be signed by all HARP collaboration members
  who took a fair number of shifts during data
  taking. After completion of data taking,
  authorship can also be justified by a major
  contribution to data analysis.

9

• Regarding Friedrichs comments
• I am surprised that such statements could be made
  without clarifying with us what the real
  situation was.
• A simple phone call or e-mail would have simply
  made it clear that
• A. the work to be done largely extends beyond
  (and independently of) the HARP data
• coding the NDA (Number of Displaced Atoms) and
  doing research on data down to 100 MeV beam
  energy
• have nothing to do with HARP data.
• B. In all likelihood much of the work will be
  done BEFORE the publication of HARP data and will
  be beneficial
• in the way that is expressed in my comment.
• C. we are certainly happy to participate (or form
  the core of) an effort to understand the
  relationship
• between what is to be published and what is
  useful for GEANT4. In any case the work will be
  done in close
• collaboration with the group of H-P. Wellisch.
• 2. certainly if such thing exists as HARP
  parametrization why should we not use it in this
  work?
• HARP parametrization is certainly a valid concept
  but parametrisation of data cannot be considered
• at the same level of intellectual property as the
  data themselves.