Feedback on 2004 priorities

Editor: J. Apostolakis

Version 1.0, 12 February 2004


This document lists the responses received to the request for feedback on the priority of proposed work items (and current requirements.) This request by email is appended as Appendix A.


Verbal feedback at G4 Technical Forum meeting


First feedback (user/s from LHC experiments):

  - Robustness/identifying problems highest priority for production

  - Performance is almost-as-high priority (and growing)


Proposed priority: Access to track properties (#0101)


Source: Petteri Nieminen (ESTEC / ESA)


[Of particular interest is] the NIEL-related requirement [submitted by] Ana Keating, and I'm sure she'll be eager to try out the new access to track property when that becomes available.


Proposed priority: Documenting the physics use cases / physics lists


[ Use case: Need to decide appropriate physics list for experiment.]

Source: Tom Roberts (, )


“IMHO documenting the physics use cases should be high on the list. The 1 paragraph descriptions on the website are inadequate. After all, physics is what geant4 is all about.


My problem involves proton-Titanium interactions at 800 MeV (at ISIS), and it was not obvious to me which use case was most appropriate. So I tried them all (:-(). That was a useful learning experience, but it would probably be better for most users if they could avoid it ....”


“About physics use cases: our experiment is about to hold a review of which physics processes of geant4 to include in our simulations. This looks to me like it will be a long, drawn-out effort. It would be great if we could simply review the dozen (or so) use cases and select from them (rather than investigating and evaluating every individual process). IMHO it is better for the experts to evaluate the processes and collect them into use cases, than for us users to try to do that; but that requires documentation, hence my suggestion before.


BTW this is the MICE experiment, which expects to run at ISIS (an 800 MeV proton synchrotron at the Rutherford Appleton Laboratory in the UK), to validate muon cooling for a future neutrino factory and/or muon collider.”


[“I think geant4 is an outstanding program infrastructure, and I applaud your team's efforts to develop and support it!“ ]


Again, THANKS!

Tom Roberts



New requirement


Source: Igor Machulin (Borexino)



“[The] Geant4 [toolkit] is intensively used by me and my colleagues for simulation of Borexino and [we] plan [to use it as well in  the] nearest  future [for the] CHOOZ-2 low energy neutrino experiments.


To simulate the main detection reaction:

    antineutrino + proton -> positron + neutron

                        (Eneutron ~ 20 keV)


it is necessary to add in GEANT4 hadronic[s] [two] processes:


a)    the capture of neutrons by Gadolinium (in CHOOZ detector we use liquid organic scintillator + 0.5% of Gd by weight).


b)    the model of neutron thermalization on hydrogen-molecules to have proper description of neutron capture time.


I would like to emphasize that Gd-loaded liquid scintillators are widely used in neutrino physics: Chooz-I, Paolo-Verde, Kamland and planned now Chooz-2 and other neutrino oscillation reactor-based experiments.


We had already developed and used in GEANT3 the models of Gd-capture and neutron thermalization for CHOOZ-I experiment. So it would be rather useful for this branch of neutrino experiments to include this processes in GEANT4 [toolkit].”


“P.S. I tried to discuss the possibility of making simple neutron thermalization model on GEANT4 User Forum with Hans-Peter Wellisch.”


Appendix A: Original email soliciting feedback


Subject:  Short opportunity for priority feedback on G4 work items in 2004


Dear colleagues,


  At Thursday's Geant4 Technical Forum meeting we presented the potential work items in geometry and hadronic physics and on areas for focus of 'overall' effort in 2004.  In presenting these potential work items & areas, we requested feedback from users on what they saw as priority items.


  This is particularly timely as the TSB will be drafting the collaboration's workplan for 2004 at its upcoming meeting next Thursday, 12th February. This leaves a short window of opportunity for you to provide feedback in advance of this meeting, by Wednesday noon, European time. 


  Please refer in particular to the presentations by G. Cosmo, H.P. Wellisch and J. Apostolakis at URL


  Despite the length of the meeting, we received valuable feedback on this from the meeting's attendees.  Yet as only a small fraction of potential interested users could be present at this meeting, the meeting chair (Albert De Roeck) and we would like to hear from others who could not be there.  In addition to your suggestions and feedback on priority, it will be helpful if you will give a short explanation of your key considerations and the area of your application and/or experiment.


  Please kindly send your feedback to <> and <>.


  Thank you in advance,


    John Apostolakis

    Makoto Asai