Gamma-ray Large Area Space Telescope

Gamma-ray Large Area Space Telescope GLAST Large Area Telescope GASU Based Trigger Systems Jim Panetta Stanford Linear Accelerator Center

GASU Based Test Stands • LAT based trigger systems • Hardware Abstractions • User Implementation • (Examples! Code!! Animatronic Dinosaurs!!!)

LAT Based Triggers • All triggers define: • Startup conditions ( TrgSequence ) • A set of data inputs ( TrgInputEnables ) • A set of conditions ( TrgConditionsValue ) • A set of actions to take ( TrgEngines ) • Ending sequence ( TrgInjectMarker )

Defining the GEM • Define setup parameters • Implement register shapes and accessors from the setup parameters • Create the hardware abstraction

Implementing the ACD Trigger • On orbit: ACD is used to veto triggers • Test stand: ACD is used to cause triggers • Implement a coincidence based system • Create list of tiles in coincidence • Define engines • Dictate trigger conditions

Coincidence Trigger System • TrgUsingTiles • Master class for a coincidence based system • Provided by LATTE • Defines a default sequence • Defines an ROI implementation ( coincidences ) • Sets the ACD into triggering mode

User Code • AcdUserExample • Implements coincidences between tiles • Specifies the input maskings • Defines the set of engines used by the trigger

User code, ctd. class AcdTriggerExample(TrgUsingTiles): """\brief ACD example interface to GEM """ def __init__(self): TrgUsingTiles.__init__(self) # it just so happens that the roi is exactly # the same as the coincidences object self.__inputEnables = MyTrgInputEnables() self.__engines = MyTrgEngines() self.__conditions = CnoCondition() self.__coincidences = self.roi() # Load the coincidences self.coincidences().addCoincidence(0,MyCoinc()) + member functions to return the above

Input, CNO, and Tile Enables class MyTrgInputEnables(TrgInputEnables): def __init__(self): TrgInputEnables.__init__(self) self.__towers = NoTowersEnabled() self.__cno = MyCnoEnables() self.__tiles = MyTileEnables() class MyCnoEnables(TrgCnoEnables): """Turn on LA1 and leave the rest off""" def LA1(self): return True class MyTileEnables(TrgTileEnables): """Enable all tiles""" def tile(self,tileNumber): return 0x3

Trigger Conditions class CnoCondition(TrgConditionsValue): """ Define a condition where only the CNO trigger is asserted""" def __init__(self): TrgConditionsValue.__init__(self) def cno(self): return True def roi(self): return False def calLow(self): return False def calHigh(self): return False def tkr(self): return False def periodic(self): return False def solicited(self): return False

Coincidences class MyCoinc0(TrgCoincidence): """This is an example of a user coincidence function. Note: The keys in the pairList dictionary *must* be unique, but the values do not have to be. """ def __init__(self): TrgCoincidence.__init__(self) self.__pairList = { 0x0 : 0x49, 0x7 : 0x41, 0x14 : 0x1F, 0x25 : 0x41, 0x37 : 0x57, } #self.__pairList2 = { AcdTileNumbering["000"] : AcdTileNumbering["001"]}

Trigger Engines class MyTrgEngines(rcTrgEngines): def __init__(self): eng = MyEngine() self.replaceEngine(1,eng) class MyEngine(TrgEngine): """This class defines an engine which reads out the detector whenever there is a CNO trigger. This engine is not prescaled. """ def __init__(self): self.__request = TrgReadout() self.__cond = CnoCondition() def participate(self,conditionsValue): condValue = self.__cond.value() if conditionsValue & condValue: return True return False

Test Code from AcdTriggerExample import * # set trigger code self.trigger( AcdTriggerExample() ) ... # enable triggers self.trigger().enable() # solicit a trigger self.trigger().solicit() # disable triggers self.trigger().disable()

Summary • Trigger is pieced into components • Each component has a function • Few components depend on others • Actual hardware is unimportant • Register shapes are unimportant

Gamma-ray Large Area Space Telescope