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0001 /*!
0002 <!-- Substitute SUBSYSTEM and PACKAGE with the proper names! -->
0003
0004 \page SUBSYSTEM_PACKAGE Package SUBSYSTEM/PACKAGE
0005
0006 <center>
0007 <small>
0008
0009
0010 <!-- @PROJ_VERS@ will be substituted at build time, no need to touch -->
0011 <a href=http://cmsdoc.cern.ch/swdev/viewcvs/viewcvs.cgi/CMSSW/SUBSYSTEM/PACKAGE/?cvsroot=CMSSW&only_with_tag=@PROJ_VERS@>CVS</a> -
0012 <a href=http://cmsdoc.cern.ch/swdev/viewcvs/viewcvs.cgi/CMSSW/SUBSYSTEM/PACKAGE/.admin/developers?rev=HEAD&cvsroot=CMSSW&content-type=text/vnd.viewcvs-markup>Administrative privileges</a>
0013 </small>
0014 </center>
0015
0016
0017 \section desc Description
0018 <!-- Short description of what this package is supposed to provide -->
0019
0020 This package implements the electronics simulation for all HCAL
0021 subsystems: HB, HE, HO, & HF.
0022
0023 \subsection interface Public interface
0024 <!-- List the classes that are provided for use in other packages (if any) -->
0025
0026
0027 \subsection modules Modules
0028 <!-- Describe modules implemented in this package and their parameter set -->
0029
0030 The parameters are mostly gotten from the calibration
0031 database. As of this writing, the pedestal values are:
0032 HB, HE, HO: 0.75 +/- 0.10 fC
0033 HF: 0.75 +/- 0.14 fC
0034
0035 and the gains are:
0036 HB, HE, HO: 0.177 +/- 0 GeV/fC
0037 HF: 0.058 +/- 0 GeV/fC (may change very soon!)
0038
0039
0040 The sampling factor, the ratio of incoming energy to sim-hit energy
0041 is 117 in HB/HE, and 217 in HO. In HF, the SimHit units are photoelectrons.
0042 HF photoelectrons correspond to 2.84 GeV of energy in the longs fibers,
0043 and 2.09 GeV in the short fibers.
0044
0045 The photostatistics factor is 2000 pe/deposited GeV in HB/HE, and 4000 in HF.
0046
0047 The amplifier gain, which goes from photoelectrons to fC, is
0048 calculated using units: pe/fC = (pe/depositedGEV) * (depositedGeV/ inc GeV) * (GeV/fC),
0049 = photostat * sampling fraction * calibration gain
0050 This comes out to 0.33 fC/pe, or an amplification of 2000.
0051
0052 The HcalTimeSlewSim does time slew at the moment, where each
0053 SimHit is delayed according to its amplitude, according to the plots
0054 in the physics TDR. Low-energy hits are delayed by 10 ns,
0055 while higher-energy hits are delayed by only 3 ns.
0056 This effect can be turned off using the "doTimeSlew" parameter.
0057
0058
0059
0060 \subsection tests Unit tests and examples
0061 <!-- Describe cppunit tests and example configuration files -->
0062
0063 The HcalDigitizerTest is meant to be a standalone
0064 test of the digitization chain.
0065
0066 We'll start with an example of an incident particle of 100 GeV energy
0067 in the HB. The sampling factor is 117, so we expect the SimHit
0068 to have 0.855 GeV of energy.
0069
0070 We next convert to photoelectrons, giving 0.855 * 2000 = 1710.
0071 These photoelectrons are subjected to Poisson statistics.
0072 Next they go through the shaping to give a pulse, still in the units
0073 of photoelectrons:
0074 DetId=1107320961, 10samples
0075 0:0
0076 1:0
0077 2:0
0078 3:0
0079 4:814.103
0080 5:657.711
0081 6:185.86
0082 7:73.7753
0083 8:31.0982
0084 9:13.2264
0085
0086 This pulse is converted to fC by multiplying by the
0087 factor of 0.33 found above. Next, this analog signal
0088 is encoded, resulting in the following digi:
0089
0090 (HE 17,1,1) 10 samples 4 presamples
0091 ADC=4, capid=1, DV
0092 ADC=4, capid=2, DV
0093 ADC=4, capid=3, DV
0094 ADC=4, capid=0, DV
0095 ADC=58, capid=1, DV
0096 ADC=54, capid=2, DV
0097 ADC=33, capid=3, DV
0098 ADC=21, capid=0, DV
0099 ADC=14, capid=1, DV
0100 ADC=9, capid=2, DV
0101
0102
0103 No noise has been added to this digi. Default running will add noise.
0104
0105 HF behaves similarly, except with a much narrower time peak.
0106 Here are the analog signals for a 100 GeV incident particle,
0107 in the long and short fibers, respectively:
0108
0109 DetId=1207987969, 6samples
0110 0:0
0111 1:0
0112 2:0
0113 3:35.2
0114 4:0
0115 5:0
0116
0117 DetId=1208004353, 6samples
0118 0:0
0119 1:0
0120 2:0
0121 3:47.8
0122 4:0
0123 5:0
0124
0125
0126 and here are the corresponding (noiseless) digis
0127
0128 HF Frames
0129 (HF 30,1,1) 6 samples 3 presamples
0130 ADC=13, capid=0, DV
0131 ADC=13, capid=1, DV
0132 ADC=13, capid=2, DV
0133 ADC=93, capid=3, DV
0134 ADC=13, capid=0, DV
0135 ADC=13, capid=1, DV
0136
0137 (HF 30,1,2) 6 samples 3 presamples
0138 ADC=13, capid=0, DV
0139 ADC=13, capid=1, DV
0140 ADC=13, capid=2, DV
0141 ADC=93, capid=3, DV
0142 ADC=13, capid=0, DV
0143 ADC=13, capid=1, DV
0144
0145
0146
0147
0148
0149
0150
0151 \section status Status and planned development
0152 <!-- e.g. completed, stable, missing features -->
0153
0154 Stable
0155
0156 <hr>
0157 Last updated:
0158 @DATE@ X. XXXX
0159 */
