beamspilltimings.fcl

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#
# File:    beamspilltimings.fcl
# Purpose: Configuration of FNAL beam time structure for GENIEHelper.
# Author:  Gianluca Petrillo (petrillo@slac.stanford.edu)
# Date:    August 19, 2019
# Version: 1.0
#
# Configurations are provided to drive GENIEGen/GENIEHelper to produce a
# neutrino interactions with time distribution reflecting the beam time
# structure.
# `evgb::GENIEHelper` determines the timing of each generated event via an
# algorithm configured via `SpillTimeConfig`. One of the available algorithms
# is specific to FNAL beams and it is implemented in `nugen` package as
# `evgb::EvtTimeFNALBeam` class, with inline documentation worth a reading
# (`nugen/EventGeneratorBase/GENIE/EvtTimeFNALBeam.h`).
# 
# The configuration is a string with the name of the algorithm first, and then
# the configuration parameters.
# 
# Configurations are provided for BnB and NuMI at some known times.
# 
# Example of usage
# -----------------
# 
# Assuming there is a configuration `generator` for `GENIEGen`, FHiCL
# configuration can be amended by appending to it:
#     
#     physics.producers.generator.SpillTimeConfig: @local::FNAL_BnB_default
#     
# 
# 
# Provided configurations
# ------------------------
# 
# * `FNAL_BnB_default`: settings from `evgb::EvtTimeFNALBeam` itself
# * `FNAL_NuMI_default`: settings from `evgb::EvtTimeFNALBeam` itself
# 
# 
# Explanation of the configuration parameters
# --------------------------------------------
# 
# This documentation reflects the configuration string of
# `evgb::EvtTimeFNALBeam` class in `nugen` `v1_00_01` (`nutools` `v3_02_00`).
# It is parsed by `evgb::EvtTimeFNALBeam::Config()` (the first word,
# representing the name of the algorithm, is stripped by the caller,
# `evgb::GENIEHelper`).
# The configuration string is, well, a single string, sequence of
# case-insensitive words separated by blanks (space, tabulation or new line).
# Parameters are parsed in sequence and the latter overrides the previous.
# Parameters may appear in any order, except for the algorithm name which must
# be the first.
# 
# * `evgb::EvtTimeFNALBeam`: the algorithm name; `evgb::EvtTimeFNALBeam`
#     describes a beam spill structured in a contiguous sequence of "batches",
#     each one with a substructure of "buckets". Some batches can be "disabled",
#     and some of the buckets at the end of each batch may be empty.
#     Each bucket has a Gaussian time distribution. See the content of
#     `nugen/EventGeneratorBase/GENIE/EvtTime*.h` for other possible algorithms.
# * `intentsity <INT 1> <INT 2> ...  <INT M>` describes the relative intensity
#     of the batches in the spill, and at the same time it defines the number
#     _M_ of batches in the spill. A standard setting is to have all the batches
#     (6 for NuMI, just 1 for BnB) set to `1.0`; `GENIEHelper` will take care of
#     normalizing the numbers to a sum of 1.
# * `sigma` or `FWHM` [ns]: the RMS or full width at half maximum peak of the
#     time structure of a single bucket. The time distribution is always
#     Gaussian (if specified as FWHM, it is converted to RMS for a Gaussian
#     distribution).
# * `dtbucket` [ns]: the time between the peak of two consecutive buckets.
#     The default value (18.83 ns) assumes an extraction rate of 53.103 MHz.
# * `nperbatch`, `nfilled`: the number of buckets in each spill, and the number
#     of those which have actual protons in them. The default values include
#     84 buckets, of which 81 are filled and the remaining 3, always at the end
#     of the spill ("notch") are empty.
# * `global` [ns]: offset of the start of the spill (i.e. the time of the peak
#     of the first bucket of the first batch) with respect to the start
#     of the generator time scale (see `detinfo::DetectorClocks`).
# * `Booster`, `NuMI`: presets including all the above in hard-coded fashion;
#     avoid using these to have better control and awareness of the settings.
# 
# Changes
# --------
# 
# 20190819 (petrillo@slac.stanford.edu) [v1.0]
#   explicitly pick settings hard-coded in `evgb::EvtTimeFNALBeam`
#

BEGIN_PROLOG

################################################################################
### Booster Neutrino Beam (BnB)
################################################################################
#
# this configuration is taken from the default settings of
# `evgb::EvtTimeFNALBeam` on `nugen` `v1_00_01` for BnB.
# According to the comments in the code, "2.0 - 2.5 ns width for Booster is
# reasonable", and "it is expected that the Booster width >> NuMI width due to
# higher electric fields / deeper buckets".
#
FNAL_BnB_default: "evgb::EvtTimeFNALBeam
intensity  1.0
sigma      2.00
dtbucket   18.8313277969
nperbatch  84
nfilled    81
global     0.0
"


################################################################################
### NuMI
################################################################################
#
# this configuration is taken from the default settings of
# `evgb::EvtTimeFNALBeam` on `nugen` `v1_00_01` for NuMI.
# According to the comments in the code, "0.75 ns sigma for NuMI comes from
# MINOS Time-of-Flight paper though it could be currently ~ 1ns".
#
FNAL_NuMI_default: "evgb::EvtTimeFNALBeam
intensity  1.0 1.0 1.0 1.0 1.0 1.0
sigma      0.75
dtbucket   18.8313277969
nperbatch  84
nfilled    81
global     0.0
"

################################################################################

END_PROLOG