KfK 5196 B Juli 1993 Extensive Air Shower Simulation with CORSIKA: A User's Manual J. Knapp, D. Heck Institut für Kernphysik Kernforschungszentrum Karlsruhe KERNFORSCHUNGSZENTRUM KARLSRUHE Institut für Kernphysik KfK 5196 B Extensive Air Shower Simulation with CORSIKA: A User's Manual J. Knapp1 and D. Heck KERNFORSCHUNGSZENTRUM KARLSRUHE GMBH, KARLSRUHE 1 Institut für Experimentelle Kernphysik, Universität Ka.rlsruhe, D-76128 Ka.rlsruhe, Germa.ny Als Manuskript gedruckt Für diesen Bericht behalten wir uns alle Rechte vor Kernforschungszentrum Karlsruhe GmbH Postfach 3640, 7500 Karlsruhe 1 ISSN 0303-4003 Abstract Extensive Air Shower Simulation with CORSIKA: A User's Manual CORSIKA is a detailed simulation program for extensive air showers initiated by high energy cosmic particles. The manual explains the installation of the code, all the necessary input datasets, the selection of simulation parameters and the structure of the program outputs. Zusammenfassung Simulation ausgedehnter Luftschauer mit CORSIKA: Eine Bedienungsanleitung CORSIKA ist ein Programm zur detaillierten Simulation von ausgedehnten Luft­ schauern, die durch hochenergetische kosmische Strahlung ausgelöst werden. Die vorliegende Anleitung erläutert die Installation des Programms, alle nötigen Eingabe­ dateien, die Wahl der Simulationsparameter und die Struktur der Ausgaben des Programms. Contents 1 Introduction 1 2 Installation 1 3 Cerenkov version 4 4 Horizontal shower version 4 5 Steering of the simulation 5 6 The particles in CO RSIKA 9 7 Running the CORSIKA program 9 8 Outputs 11 9 In case of problems ... 12 Bibliography 12 lll 1 Introd uction CORSIKA (COsmic Ray Simulations for KAscade) is a detailed Monte Carlo pro­ gram to study the evolution of EAS in the atmosphere initiated by photons, protons or nuclei of energies up to 1017 eV. It was developed to perform simulations for the KASCADE experiment [1] presently under construction at Karlsruhe. The CORSIKA program [2] is a complete set of routines written in standard FORTRAN77 including the EGS routines [3] modified for the use in extensive air shower simulation. No additional programlibraries are required. Therefore, it runs without problems on all computers where FORTRAN77 is available. The program e:Xists in several types. The standard one allows to simulate the hadronic and muonic component of extensive air showers with or without the detailed simulation of the electromagnetic particles. Optionally versions are available to model in addition the generation of Cerenkov light in the atmosphere and showers under horizontal incident directions. A detailed description of the hadronic and electromagnetic interaction models, the cross sections, the particle decays, and the program frame has been published in [2]. This report is a supplementary description of the technical handling of COR­ SIKA. It contains information about the installation of the program, the required input data, file formats, parameter settings, outputs, and some technical details. If you have proble1ns in installing or running the program, suggestions to im­ prove the code concerning physics, computing, or handling, please contact : Dr. J. Knapp Dr. D. Heck Institut für Kernphysik 1 Institut für Kernphysik 3 Kernforschungszentrum Karlsruhe Kernforschungszentrum Karlsruhe Postfach 3640 Postfach 3640 D-76021 Karlsruhe D-76021 Karlsruhe Tel.: 0721-82-3549 Tel.: 0721-82-3777 Fax.: 0721-82-3548 Fax.: 0721-82-4075 E-mail: IKP977 at DKAKFK3.BITNET E-mail: IAK077 at DKAKFK3.BITNET 2 Installation The CORSIKA source is kept as a HISTORIAN file. HISTORIAN [4] allows com­ fortably to keep several versions of one program with optional code by some simple commands and definitions. Users who do not have HISTORIAN available may eas­ ily understand the source file when knowing the following HISTORIAN commands: *DK 'name' defines beginning of deck 'name'. A deck may be a subroutine, function, part of code etc. 1 *CD 'name' defines beginning of common deck 'name' that is defined once and used multiple (e.g. COMMON blocks). *CA 'namel,name2, ... ' includes common decks 'namel', 'name2', ... at this place. *IF DEF,logkey *EI the code between *IF and *EI is only used if the logical variable logkey is set. The code after a *IF -DEF ,logkey is used if logkey is not set. *IF ... *EI blocks may be nested. U nmarked code is used in any case. At present code for the following logical variables exists in CORSIKA: IBM selects code for calculation on the IBM3090 (machine dependent i/o opera­ tions) TRANSP selects code for calculation on the Transputerfarm (machine dependent i/ o operations) CERENK selects code for simulation of Cerenkov light HORIZONT selects code for simulation of nearly horizontal showers INTTST selects special features for the test of the interaction model (not yet com­ plete, do not use!!) Only a few per cent of the code is optional. With these remarks it should be possible to understand the source code in case of problems. The CORSIKA distribution set consists of the source code (SOURCE) in HIS­ TORIAN format, that contains the complete code, two compile files of the stan­ dard CORSIKA (COMPIBM) and of the Cerenkov version (COMPIBMC), two datasets containing the energy dependent cross sections for electromagnetic interac­ tions (EGSDATA) and nucleon-nucleus processes (NUCNUCCS), several datasets with atmospheric data for different large inclination angles (ATMxx), an example input (INPUTS) tosteer the simulation, a I~TffiXfile containing this description, and a brief description of the changes in the program since the last version. The program comprises some explanations, one main program and ca. 100 sub­ routines and functions and is ~ 16000 lines long. The cross sections for the EGS4 routines are contained in the dataset EGSDATA with a length of 901lines. It is connected to the logical unit KMPI (by default 12). The nucleon-nucleus cross sections are listed in NUCNUCCS which is 2873lines long. They are read via logical unit NUCNUC (NUCleus-NUCleus interactions, by default 11 ). The program version for horizontal showers requires additional data on the at­ mosphere's density (501 lines ). They are expected to be stored in ATMOSPH and are requested via logical unit ATMI (ATMosphere Input, by default 44). Beside these two datasets CORSIKA needs the input of steering commands to 2 Name Def. I/0 File KMPI 12 I EGSDATA, EGS cross sections NUCNUC 11 I NUCNUCCS, nucleus-nucleus cross sections ATMI 44 I ATMOSPH, atmosph. data for horiz. showers MONIIN 5 I INPUTS, steering cards MONIOU 6 0 Simulation cantroll output on line printer MDEBUG 99 0 Debug output if DEBUG it selected EXST 96 I/0 External particle stack, temporary datset PATAPE 90 0 Partide output and simulation results CETAPE 91 0 Cerenkov photon output Table 1: Logical units for in- and output with their default values select the subject of the simulation. They are read via logical unit MONIIN (MONI­ tor INput, by default 5). The format ofthe steeringcards and their effect is described in detail is sec. 5. There are several streams of the output of CORSIKA. One is control informa­ tion about the simulation run itself which is directed to the logical unit MONIOU (MONitor OUtput, by default 6). In case of a debugging run very much information is written to the logical unit MDEBUG (Monitor for DEBUGging, by default 99). The second output stream contains the information about all the particles that reach the observation level. It is directed to unit PATAPE (PArticle TAPE, by default 90). A last output file contains the compressed information of the Cerenkov photons. It is directed to unit CETAPE (CErenkov TAPE, by default 91). During the calculation the program uses a temporary dataset as an external particle stack if the internal one is overfull. This data set is connected to unit EXST (EXi;ernal STack, by default 96). The values of the in- and output units may be redefined by changing their values in one of the two BLOCK DATA subprograms. The units are listed with their default values in table 1. As the CORSIKA program was developed to run on any FORTRAN machine, the major part of the program is machine independent by using only FORTRAN77 standard statements. Nevertheless, there are a few points where computer specific changes may be necessary, concerning for example the file types and connections for in- and output, some code to avoid time out and end of tape errors on our IBM3090, and the rou­ tines delivering an actual date and time. Those crucial places are marked with the comment lines 3 C--MACHINE DEPENDENT CODE C--MACHINE DEPENDENT CODE in the code. 3 Cerenkov version The routines treating the Cerenkov radiation have been supplied by the HEGRA Collaboration and are not described in the CORSIKA report [2). The Cerenkov light production by electrons, positrons, and hadrons is considered in the routines CERENE and CERENH respectively. The photons are restricted to the wavelengths band of 300 to 450 nm. Atmospheric absorption of the Cerenkov photons is not taken into account. Charged particles create Cerenkov photons at each tracking step when the con­ dition ß > 1/n (ß = vjc and n = refractive index) is fullfilled. The step is subdivided in smaller substeps such that the number of Cerenkov photons per substep is less than the fixed number CERSIZ, predifined by an input data card. In such a substep all the photons are sent in a compact bunch along a straight line, defined by the emission angle Be relative to the electron's or hadron's direction and a random value for the angle rjJ around this direction. For higher primary energies it is still impossible to write all the bunches of one shower to tape. Therefore only the bunches are recorded which hit an array of 27 x 27 squares of 1 m 2 each and a gridspacing of 15 m at observation level. Each bunch is represented by 7 words which are the number of Cerenkov photons, the x and y coordinates at the observation level, direction cosines u and v, arrival time and height of production above sea level.