Guidelines for GSIM Focus Group Simulation Proposals (DRAFT 2)

Last updated 11 September 1998

The GSIM Focus Group's purpose is to facilitate the calculation of acceptance functions for CLAS experiments for the first publications. Since limited CPU resources are available, it is important to coordinate simulation requests to provide optimal calculations for every group which is poised to make use of them. These guidelines are intended to help with the development of the best possible run request proposals.

Communication with the group

Each proposal should be informally presented to the GSIM Focus Group at one of the weekly meetings, preferably by the requesters. This may be relaxed for overseas collaborators. The purpose is to clarify the detailed requirements of the proposal, to understand the need for the statistics requested, and to provide input and support to the acceptance calculation.

The group is eager to help in developing these proposals and to offer support for providing the optimal calculation.

Number of simulated events requested

The number of simulated events requested should be based on quantitative estimates for the errors required for the acceptance calculation. It should be considered whether relative or absolute errors are important. (If the number requested is less than 100,000, estimates are not needed.) In some cases, special additional studies may be needed in addition to the pure statistical count, such as for background studies.

Some information on error estimates is available on the web:
acceptance error calculations acceptance error plots

The number of simulated events should be reasonably commensurate with the number of experimental data events, both signal and background.

Event generators

Some support is available in providing event generators and help in operating them, but this is primarily the responsibility of the proposer. Event generators used to date include the CELEG event generator, the radiated AO generator, a radiated elastic scattering generator, and a collection of special purpose phase space generators. There is a separate but related group focusing on event generator development in cooperation with the GSIM Focus Group.

Prototype runs

Every proposer should plan to begin with a prototype run (e.g. 100,000 events). The run should be analyzed to make sure all problems are worked out before investing resources in longer runs.

Status of analysis

It should be demonstrated that the data analysis for a particular reaction is sufficiently advanced so that the simulated data can be immediately analyzed.

Conferences and presentations

Calculations for people making presentations at upcoming conferences, PAC meetings, etc. will be given higher priority, as long as sufficient advance notice is given of the request.

Students

Calculations for PhD students working on their theses will be given higher priority.

Checklist for proposals

Absolute acceptance errors have been calculated in a given binning scheme Range of errors is:
Relative acceptance errors have been calculated in a given binning scheme. Range of errors is:
Date results are needed:
Is request in support of a formal presentation? Date and nature of presentation? (e.g., conference date)
How many events are requested, under what running conditions? Specify magnetic field of torus and other magnets (minitorus, polarized target):
GSIM documentation has been reviewed to make sure what is included in the simulation is appropriate (documentation coming soon)
Photon beam or electron beam? Other special geometries to use? (Start counter in/out, minitorus in/out, polarized target geometry in/out, photon beam target or electron beam target, etc)
Has a prototype run been performed?
Any other special points? (e.g, single particle runs)
Input event files to be provided (determine optimal size from prototype run) , or else what event generators should be used? (CELEG, radiated AO, radiated elastic)