Changeset 152 in JEM-EUSO


Ignore:
Timestamp:
May 16, 2013, 10:17:48 AM (11 years ago)
Author:
moretto
Message:

version de la nuit du mercredi 15 mai

Location:
ICRC2013/EusoBalloonDetector/trunk
Files:
6 edited

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  • ICRC2013/EusoBalloonDetector/trunk/icrc2013-EBDet-morettodagoret.aux

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    1717\citation{bib:EUSOperf}
    1818\citation{bib:EBpath}
     19\citation{bib:EBSimulation}
    1920\@writefile{toc}{\contentsline {section}{\numberline {1}Introduction}{1}{section.1}}
     21\@writefile{toc}{\contentsline {section}{\numberline {2}The Instrument overview}{1}{section.2}}
     22\newlabel{sec:OverviewInstrument}{{2}{1}{The Instrument overview\relax }{section.2}{}}
    2023\citation{bib:Optics}
     24\citation{bib:FrontEndEl}
    2125\@writefile{lof}{\contentsline {figure}{\numberline {1}{\ignorespaces EUSO-Balloon Instrument Overview.}}{2}{figure.1}}
    2226\newlabel{fig:globalview}{{1}{2}{EUSO-Balloon Instrument Overview}{figure.1}{}}
    23 \@writefile{toc}{\contentsline {section}{\numberline {2}The Instrument Overview}{2}{section.2}}
    24 \newlabel{sec:OverviewInstrument}{{2}{2}{The Instrument Overview\relax }{section.2}{}}
    2527\@writefile{toc}{\contentsline {subsection}{\numberline {2.1}General characteristics and functions}{2}{subsection.2.1}}
    2628\@writefile{toc}{\contentsline {subsection}{\numberline {2.2}Instrument structure}{2}{subsection.2.2}}
    2729\@writefile{lot}{\contentsline {table}{\numberline {1}{\ignorespaces Typical parameters of the instrument}}{2}{table.1}}
    2830\newlabel{tab:properties}{{1}{2}{Typical parameters of the instrument\relax }{table.1}{}}
    29 \@writefile{toc}{\contentsline {section}{\numberline {3}The Instrument Subsystems}{2}{section.3}}
    30 \newlabel{sec:Subsystems}{{3}{2}{The Instrument Subsystems\relax }{section.3}{}}
     31\@writefile{toc}{\contentsline {section}{\numberline {3}The Instrument subsystems}{2}{section.3}}
     32\newlabel{sec:Subsystems}{{3}{2}{The Instrument subsystems\relax }{section.3}{}}
    3133\@writefile{toc}{\contentsline {subsection}{\numberline {3.1}Optics subsystem}{2}{subsection.3.1}}
    32 \citation{bib:FrontEndEl}
    3334\citation{bib:ASIC}
    3435\citation{bib:CCB}
     
    5253\bibcite{bib:FrontEndEl}{5}
    5354\bibcite{bib:ASIC}{6}
    54 \bibcite{bib:CCB}{7}
    55 \bibcite{bib:Calib}{8}
    56 \bibcite{bib: PMT}{9}
    57 \bibcite{bib:OffOnLineAna}{10}
    58 \@writefile{toc}{\contentsline {section}{\numberline {4}Assembly and Tests}{4}{section.4}}
    59 \newlabel{sec:AssemblyTest}{{4}{4}{Assembly and Tests\relax }{section.4}{}}
     55\@writefile{toc}{\contentsline {section}{\numberline {4}Assembly and tests}{4}{section.4}}
     56\newlabel{sec:AssemblyTest}{{4}{4}{Assembly and tests\relax }{section.4}{}}
    6057\@writefile{toc}{\contentsline {subsection}{\numberline {4.1}The optical tests}{4}{subsection.4.1}}
    6158\@writefile{toc}{\contentsline {subsection}{\numberline {4.2}Measuring the MAPMT performances}{4}{subsection.4.2}}
     
    6562\@writefile{toc}{\contentsline {section}{\numberline {5}Operation and Analysis}{4}{section.5}}
    6663\newlabel{sec:Operation}{{5}{4}{Operation and Analysis\relax }{section.5}{}}
     64\@writefile{toc}{\contentsline {section}{\numberline {6}Conclusion}{4}{section.6}}
     65\newlabel{sec:Conclusion}{{6}{4}{Conclusion\relax }{section.6}{}}
     66\bibcite{bib:CCB}{7}
     67\bibcite{bib:Calib}{8}
     68\bibcite{bib: PMT}{9}
     69\bibcite{bib:OffOnLineAna}{10}
  • ICRC2013/EusoBalloonDetector/trunk/icrc2013-EBDet-morettodagoret.log

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  • ICRC2013/EusoBalloonDetector/trunk/icrc2013-EBDet-morettodagoret.out

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    11\BOOKMARK [1][-]{section.1}{Introduction}{}% 1
    2 \BOOKMARK [1][-]{section.2}{The Instrument Overview}{}% 2
     2\BOOKMARK [1][-]{section.2}{The Instrument overview}{}% 2
    33\BOOKMARK [2][-]{subsection.2.1}{General characteristics and functions}{section.2}% 3
    44\BOOKMARK [2][-]{subsection.2.2}{Instrument structure}{section.2}% 4
    5 \BOOKMARK [1][-]{section.3}{The Instrument Subsystems}{}% 5
     5\BOOKMARK [1][-]{section.3}{The Instrument subsystems}{}% 5
    66\BOOKMARK [2][-]{subsection.3.1}{Optics subsystem}{section.3}% 6
    77\BOOKMARK [2][-]{subsection.3.2}{Front-End Electronics}{section.3}% 7
     
    99\BOOKMARK [2][-]{subsection.3.4}{Monitoring}{section.3}% 9
    1010\BOOKMARK [2][-]{subsection.3.5}{Power supply and electrical architecture}{section.3}% 10
    11 \BOOKMARK [1][-]{section.4}{Assembly and Tests}{}% 11
     11\BOOKMARK [1][-]{section.4}{Assembly and tests}{}% 11
    1212\BOOKMARK [2][-]{subsection.4.1}{The optical tests}{section.4}% 12
    1313\BOOKMARK [2][-]{subsection.4.2}{Measuring the MAPMT performances}{section.4}% 13
     
    1616\BOOKMARK [2][-]{subsection.4.5}{The Instrument tests}{section.4}% 16
    1717\BOOKMARK [1][-]{section.5}{Operation and Analysis}{}% 17
     18\BOOKMARK [1][-]{section.6}{Conclusion}{}% 18
  • ICRC2013/EusoBalloonDetector/trunk/icrc2013-EBDet-morettodagoret.tex

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    4747
    4848%The abstract.
    49 \abstract{EUSO-Balloon is a pathfinder prefiguring the future fluorescence space telescope JEM-EUSO that should be installed on-board the Internal Space Station before the end of this decade.
     49\abstract{EUSO-Balloon is a pathfinder prefiguring the future fluorescence space telescope JEM-EUSO that should be installed on-board the International Space Station before the end of this decade.
    5050This telescope will be the payload of a stratospheric balloon operated by CNES, starting its flight campaign in 2014.
    51 Current technical developments for JEM-EUSO have been implemented in EUSO-Balloon.
    52 In this article, the complete design of this instrument will be presented. It consists of an advanced telescope structure, including a set of three Fresnel lenses having an excellent focusing performance onto its pixelized UV Camera. This camera is very sensitive to single photons, accepting signals within 6 orders of magnitude through an adaptive gain, and able to observe speed-of-light phenomena. The camera is an array of multi-anodes photomultipliers, whose dynodes are driven by Crockoft Walton HV generators capable of switching down the gain in few microseconds to protect the photodetectors against strongly luminous events.
    53 Analog signals of the anodes are digitised continuously each time window (2.5 $\mu$s) by ASICs, performing two kinds of signal measurements and readout by a FPGA applying a first level trigger algorithm.
    54 The electronics is operated by a digital processing unit comprising a CPU associated to Clocks generators board and a GPS receiver, an event filtering board based on a FPGA and an House-Keeping unit for the instrument monitoring. The CPU controls both acquisition and the data storage.
    55 This processing unit is interfaced with the CNES telemetry system to receive commands from ground and to download samples of the event or monitoring data.
    56 The whole instrument operates autonomously %with a battery package that drives a series of power supply boards that deliver the required voltage to each board.
     51Current technical developments for JEM-EUSO have been implemented in EUSO-Balloon. The complete design of this instrument is presented. It consists of an advanced telescope structure, including a set of three Fresnel lenses having an excellent focusing performance onto its pixelized UV Camera. All the stages of the signal processing are reviewed from the photodetector, the analog electronics producing the digitised data, and also the triggers selecting the events while rejecting the random background, the acquisition system allowing the data storage and the monitoring permitting the instrument control during operation. The key parameters of the instrument are presented and their chosen value motivated.
     52%This camera is very sensitive to single photons, accepting signals within 6 orders of magnitude through an adaptive gain, and able to observe speed-of-light phenomena. The camera is an array of multi-anodes photomultipliers, whose dynodes are driven by Crockoft Walton HV generators capable of switching down the gain in few microseconds to protect the photodetectors against strongly luminous events.
     53%Analog signals of the anodes are digitised continuously each time window (2.5 $\mu$s) by ASICs, performing two kinds of signal measurements and readout by a FPGA applying a first level trigger algorithm.
     54%The electronics is operated by a digital processing unit comprising a CPU associated to Clocks generators board and a GPS receiver, an event filtering board based on a FPGA and an House-Keeping unit for the instrument monitoring. The CPU controls both acquisition and the data storage.
     55%This processing unit is interfaced with the CNES telemetry system to receive commands from ground and to download samples of the event or monitoring data.
     56%The whole instrument operates autonomously. %with a battery package that drives a series of power supply boards that deliver the required voltage to each board.
    5757}
    5858
     
    6666
    6767\section{Introduction}
    68 EUSO-Balloon is a telescope aiming at verifying the conceptual design as well as the technologies foreseen to be applied for the construction of the future space telescope JEM-EUSO ~\cite{bib:EUSOperf}. Even if this instrument is a reduced version of JEM-EUSO, it however includes almost all the required components of the original space mission. The scientific and technical goals on its mission are reviewed in the reference~\cite{bib:EBpath}. This instrument will be the payload of a stratospheric balloon operated by CNES, 
     68EUSO-Balloon is a telescope aiming at verifying the conceptual design as well as the technologies foreseen to be applied for the construction of the future space telescope JEM-EUSO ~\cite{bib:EUSOperf}. Even if this instrument is a reduced version of JEM-EUSO, it however includes almost all the required components of the original space mission. The scientific and technical goals of its mission are reviewed in~\cite{bib:EBpath}.
     69The physical performances if the instrument are estimated in~\cite{bib:EBSimulation}.
     70This instrument will be the payload of a stratospheric balloon operated by CNES, 
    6971to perform a series of night-flights at altitudes of 40 km, at various earth locations, lasting from a few hours to tens of hours. This program requires payload recovery after landing either in water or hard soil, and repairing after each mission. The special atmospheric environmental conditions and recovery requirements involve much precautions in the design and imply dedicated tests with the realisation of prototypes.
    7072
     
    7274
    7375
    74 \section{The Instrument Overview}
     76\section{The Instrument overview}
    7577\label{sec:OverviewInstrument}
    7678
     
    8587  \label{fig:globalview}
    8688 \end{figure}
    87  The instrument includes an external roof-rack permitting the fixation of complementary instrument like an infra-red camera for atmosphere monitoring.
     89 The instrument includes an external roof-rack permitting the fixation of complementary instruments like an infra-red camera for atmosphere monitoring.
    8890 
    8991 
     
    101103The mechanics of the instrument is made of Fibrelam\textregistered \ panels, arranged together through fibreglass sections.
    102104The instrument is coated by an insulating cover to protect the instrument's components from fast temperature changes during balloon ascent and descent.
    103 Special watertight valves inserted in the optical bench are used to enable pressure equilibrium with the atmosphere. Wherever the after-flight landing location occurs, the instrument must be recovered  with the smallest damages.
     105Special watertight valves inserted in the optical bench are used to enable pressure equilibrium with the external environment. Wherever the after-flight landing location occurs, the instrument must be recovered  with the smallest damages.
    104106The bottom part is equipped with crash-pads which absorb brutal deceleration (up to 15 G) when landing on ground. A baffle with special holes in the optical bench are used as a piston-effect to damp the shock for a fall over water.
    105107The instrument booth which is a totally watertight sealed box, consists of a central aluminium plate on which the various electronic boxes are fixed. One of its side is the third lens. The opposite one is an aluminium radiator used to dissipate the heat generated by electronics equipments.
    106108The instrument is surrounded by buoys to avoid sinking in case of splashdown and to raise straight up the instrument booth above the water level.
    107 \section{The Instrument Subsystems}
     109
     110\section{The Instrument subsystems}
    108111\label{sec:Subsystems}
    109112The instrument is broken down into subsystems defined to be the optics, the Focal Surface (FS), the photodetector with the MAPMTs, the signal measurement with the ASICs, the trigger readout with the Photo-Detector Module Board (PDMB) and the Cluster Control Board (CCB). The Data Acquisition System (DAQ) and the utilities like the monitoring also called the House-Keepting (HK) and the power supplies. Those subsystems are all described below. 
     
    118121\paragraph{Focal Surface} The focal surface is a slightly curved surface, similarly to that of the JEM-EUSO central PDM. It is an array of 48$\times$48 pixels of 2.88 mm $\times$ 2.88 mm size exceeding slightly the focal point spread. Practically, the focal surface of the PDM is broken up into a set of 9 identical Elementary Cells (ECs), which are matrices of 2$\times$2 MAPMTs. The photocathode is covered by a BG3 UV filter. Inside the PDM structure, the 9 ECs are disposed and tilted according to the appropriate shape required for the FS.
    119122
    120 \paragraph{MAPMTs} They are photon detectors consisting of a matrix of 8$\times$8 pixels. Each pixel is associated to an anode generating a charge or a current in output. Their sensitivity is as low as a few tens of photoelectrons and their dynamic range can extend up to few thousands photoelectrons per $\mu$s when working at high gain ($10^6$).
     123\paragraph{MAPMTs} They are photon detectors consisting of a matrix of 8$\times$8 pixels. Each pixel is associated to an anode generating a charge or a current in output. Their sensitivity is as low as a few tenths of photon and their dynamic range can extend up to few thousands photon per $\mu$s when working at their nominal high gain, $10^6$.
    121124
    122125\paragraph{High voltage power supply}
    123 MAPMTs require to be polarised with 14 high voltages. The latter are generated by a high voltage power supply (Crockoft-Walton type to \hyphenation{li-mits} the power consumption). The nominal high voltage of the photocathode is -900 V for a MAPMT gain of $10^6$. The effective dynamic range can be extended up to 10$^7$ photons/$\mu$s by reducing gradually the gain down to 30. Fast switches reactive at $\mu$s time scale adapt HV values to tune the MAPMT gain according to the intensity of photon flux.
    124 Because a large photon flux generating anode current above 100$\mu$A would destroy the tube, this automatic control system can even switch off the gain. Practically this switching decision logic is implemented in a FPGA reading out the \mbox{ASICs}. In the PDM, there is 9 independent HVPS controlling the 9 ECs.
    125 
    126 
    127 \paragraph{ASICs} 36 SPACIROC~\cite{bib:ASIC} type ASICs are used to perform the anode signals measurement and digitisation of the 36 MAPMTs. These ASICs have 64 channels. Their analog inputs are DC-coupled to the MAPMT anodes. They process the 64 analog signals in parallel in two modes : 1) in photoelectron counting mode, in a range from 1/3 of photoelectrons up to 100 photoelectrons, by discriminating over a programmed threshold each of the channels, 2) by estimating the charge from 20~pC to 200~pC, by time over threshold determination for exclusive groups of 8 anodes current sums. The 64 analog channels are balanced each-other relatively by gain matching over 8-bits.
     126MAPMTs require to be polarised with 14 high voltages. The latter are generated by a high voltage power supply (Crockoft-Walton (CW) type to restrain the power consumption). The nominal high voltage of the photocathode is -900 V for a MAPMT nominal gain at $10^6$. The effective dynamic range can be extended up to 10$^7$ photons/$\mu$s by reducing gradually the gain down to 30. Fast switches (SW) responsive at $\mu$s timescale, adapt HV values to tune the MAPMT gain according to the intensity of photon flux.
     127Because a large photon flux generating anode current above 100$\mu$A would destroy the tube, this automatic control system can even switch off the gain. Practically this switching decision logic is implemented in a FPGA reading out the \mbox{ASICs}. In the PDM, there is 9 independent CW with their individual 9 SW, assembled into two separated HVPS boxes, each CW controlling independently the 9 ECs High Voltages.
     128
     129
     130\paragraph{ASICs} 36 SPACIROC~\cite{bib:ASIC} type ASICs are used to perform the anode signals measurement and digitisation of the 36 MAPMTs. These ASICs have 64 channels. Their analog inputs are DC-coupled to the MAPMT anodes. They process the 64 analog signals in parallel in two modes : 1) in photoelectron counting mode, in a range from 1/3 of photoelectrons up to 100 photoelectrons, by discriminating over a programmed threshold each of the channels, 2) by estimating the charge from 20~pC to 200~pC, by time over threshold determination for exclusive groups of 8 anodes current sums from clusters of 8 contiguous pixels. The 64 analog channels are balanced each-other relatively by gain matching over 8-bits.
    128131The discrimination voltage level used in the photon-counting is provided by a 10-bit DAC (Digital to Amplitude converter).
    129132In both cases the digitisation is performed by 8-bits counters every GTU. There is no data buffering on the ASIC. The data are transferred to the FPGA each GTU under the sequencing frequency of a 40MHz clock.
    130133
    131 \paragraph{Trigger} The Instrument includes two trigger stages. The level 1 trigger (L1) implemented in the FPGA (Xinlinks Virtex 6) of a PDM-Board (PDMB), belonging to the Front-End Electronics. The PDMB readouts the data from the 36 ASICs into its internal memory (the event buffer) each GTU to compute the trigger L1. Its principle consists in counting an excess of signals over background in groups of 3$\times$3 pixels lasting more than a preset persistence time. The background rate seen by pixel is monitored continuously to adjust in real-time the trigger threshold which is adjusted such as the L1 rate is kept at a fixed level of a few Hz compatible with the DAQ recording rate. The trigger is evaluated each GTU. Because Air-Showers may extend over 100 GTU, this trigger has the buffering capability of 128 consecutive GTU.
     134\paragraph{Trigger} The Instrument includes two trigger stages. The level 1 trigger (L1) implemented in the FPGA (Xilinks Virtex 6) of a PDM-Board (PDMB), belonging to the Front-End Electronics. The PDMB readouts the data from the 36 ASICs into its internal memory (the event buffer) each GTU to compute the L1 trigger. Its principle consists in counting an excess of signals over background in groups of 3$\times$3 pixels lasting more than a preset persistence time. The background rate seen by pixel is monitored continuously to adjust in real-time the trigger threshold which is adjusted such as the L1 rate is kept at a fixed level of a few Hz compatible with the DAQ recording rate. The trigger is evaluated each GTU. Because Air-Showers may extend over 100 GTU, this trigger has the buffering capability over 128 consecutive GTU.
    132135To reduce the dead-time induced by event readout, the event buffer is doubled.
    133136
    134137\subsection{Data acquisition}
    135138The data acquisition system is part of the computing system DP (Data Processing).
    136 It comprises the CCB designed to produce the second level trigger L2, which is described in~\cite{bib:CCB}. For each generated L1 trigger, the CCB reads the data corresponding to the 128 consecutive GTU from the PDMB buffer. In JEM-EUSO, the CCB is devoted to the combination of 9-PDMB triggers and to reduce the resulting combined trigger rate to about a few Hz or less compatible with the data storage capabilities of the DAQ. The triggering role of the CCB in EUSO-Balloon is marginal as there is only one PDM. However it has the task to read the whole event from the Front-End and to pass it to the CPU. The L2 decision is propagated to the Clock-Board (CLK-B, based on a Xilinks Virtex5 FPGA) generating all the clocks used by the electronics, itself associated with a GPS-Board to provide the event time tagging data with an accuracy of a few microseconds.
     139It comprises the CCB designed to produce the second level trigger L2, which is described in~\cite{bib:CCB}. For each generated L1 trigger, the CCB reads the data corresponding to the 128 consecutive GTU from the PDMB buffer. In JEM-EUSO, the CCB is devoted to the combination of 9-PDMB triggers and to reduce the resulting combined trigger rate to about a few Hz or less compatible with the data storage capabilities of the DAQ. The triggering role of the CCB in EUSO-Balloon is marginal as there is only one PDM. However it has the task to read the whole event from the Front-End and to pass it to the CPU. The L2 decision is propagated to the Clock-Board (CLKB, based on a Xilinks Virtex5 FPGA) generating all the clocks used by the electronics, itself associated with a GPS-Board to provide the event time tagging data with an accuracy of a few microseconds.
    137140The CPU (Motherboard iTX-i2705 model, processor  Atom N270 1.6 GHz)  merges the event data with the time tagging data to build an event of a size of 330 kB, leading to a data flow of 3MB/s for a 10 Hz L1-L2 trigger. The CPU write all the data on disks (1 TB CZ Octane SATA II 2.5Ó SSD) and may also send to telemetry a subset of flagged events by CCB for event monitoring.
    138141
    139142\subsection{Monitoring}
    140 The instrument behaviour is controlled at low frequency by the House-Keeping system (HK) which is a part of DP. It is based on a commercial micro controller board (Arduino Mega 2560) designed to control temperatures, voltages, and alarms raised by several boards. The CPU poll from time to time the alarms and initiate corresponding foreseen actions. HK is connected to the telemetry system to receive basic commands namely those that allow to turn on-off most of the boards power supplies through relay control.
     143The instrument behaviour is controlled at low frequency by the House-Keeping system (HK) which is a part of DP. It is based on a commercial micro controller board (Arduino Mega 2560) designed to control temperatures, voltages, and alarms raised by several boards. The CPU poll from time to time the alarms and initiate corresponding foreseen actions. HK is connected to the telemetry system to receive basic commands namely those that allow to turn on-off most of the boards power supplies through relays.
    141144
    142145\subsection{Power supply and electrical architecture}
    143 The instrument runs autonomously thanks to a set of 60 battery cells providing 28 V (225 W during 24 H) to a set of Low-Voltage boards generating isolated-decoupled lower voltages to the PDM (HVPS and PDMB), DP (CPU, CCB and HK). The electrical architecture follows the EMC rules to prevent  floating reference voltage  induced by bad grounding (ground current loop effect).
    144 
    145 \section{Assembly and Tests}
     146The instrument runs autonomously thanks to a set of 60 battery cells providing 28 V (225 W during 24 H) to a set of Low-Voltage boards generating isolated-decoupled lower voltages to the PDM (HVPS and PDMB), DP (CPU,CLKB,GPSB,CCB and HK). The electrical architecture follows the EMC rules to prevent floating reference voltages induced by bad grounding (current ground loop effect).
     147
     148\section{Assembly and tests}
    146149\label{sec:AssemblyTest}
    147150After fabrication, the subsystems directly related to the physics measurements need to be calibrated in an absolute way.
     
    152155
    153156\subsection{The optical tests}
    154 Even if the focal length of each lens and the combined focal length can be predicted by calculation, the real values resulting from the machining are poorly known at several centimetres accuracy. This is not enough to achieve a resolution smaller than the pixel size. The relative distance between the three lenses and the Focal Surface has to be measured experimentally by using a large parallel UV beam along optical axis, sent over the first lens and measuring the Focal Length by adjusting the position of a CCD camera to get a narrow point-like focused spot.
     157Even if the focal length of each lens and the combined focal length can be predicted by calculation, the real values resulting from the machining are poorly known, only at a few tens of centimetres accuracy. This is not enough to achieve a resolution smaller than the pixel size. Thus the relative distance between the three lenses and the Focal Surface has to be measured experimentally by using a large parallel UV beam along optical axis, sent over the first lens and measuring the Focal Length by adjusting the position of a CCD camera to get its position obtained for the narrowest focused spot.
    155158
    156159\subsection{Measuring the MAPMT performances}
    157 Each channel of the MAPMT is characterised by its photodetection efficiency (product of the photocathode quantum efficiency and the collection efficiency) and by the gain of the phototubes. This efficiency is firstly measured before the mounting of MAPMTs inside EC-Units (see~\cite{bib: PMT}) and also after the EC-Units assembly.
    158 This measurement is done by illuminating the photocathode with a LED (monitored with a NIST-photodiode). The MAPMT operates in single photoelectron mode~\cite{bib:Calib} to measure the single photoelectron spectrum for each of the 2304 pixels of the instrument camera.
    159 This procedure allows to determine the exact high voltage to apply to each MAPMTs photocathodes.
     160Each channel of the MAPMT is characterised by its photodetection efficiency and by the gain of the phototubes.
     161Before associating sets of 4 MAPMTs into EC, the MAPMTs are sorted according their gain to get EC with MAPMT with close gain for the same HV(see~\cite{bib: PMT}).
     162For this, the gain are initially measured with sensitive, commercial multi-channels charge converters (QDC) for a gain, being a factor three above its nominal value, for a HV around -1100~V.
     163Once the EC are assembled, the gain and the detection efficiency for each channels are measured with the ASICs at the nominal HV at -900~V.
     164This operation is called the calibration.
     165Both types of measurements are done with by illuminating the photocathode with a LED (monitored with a NIST-photodiode). The MAPMTs operates in single photoelectron mode~\cite{bib:Calib} to measure the single photoelectron spectrum for each of the 2304 pixels of the instrument camera.
     166This procedure allows to determine the exact high voltage to apply to the MAPMTs photocathodes  of each EC Units.
     167
    160168\subsection{The ASIC settings}
    161169The ASICs measure the single photoelectron spectra at nominal high voltage for each of the channels by performing S-curve (by performing series of runs by ramping the discriminator voltage).
     
    163171
    164172\subsection{The Trigger tests}
    165 Once the PDM is mounted, the L1 trigger algorithm performance is checked by illuminating the Focal Surface by the light spot moving closely to speed-of-light, generated by an "old" persistent-screen scope.
     173Once the PDM is mounted, including the PDMB, the L1 trigger algorithm performance is checked by illuminating the Focal Surface by the light spot moving closely to speed-of-light, generated by an "old" persistent-screen scope.
    166174
    167175\subsection{The Instrument tests}
    168176The final tests will be performed after the integration of all subsystems inside the instrument. A check of the correct final position of the lenses  as well as that of the Focal Surface will be done by lighting up the first lens by a parallel UV beam along the optical axis. The size of the focused point on the Focal surface will be minimised by finely adjusting the position of the PDM at the sub-millimetre scale.
    169 At the end of  the integration and at launch site, basic health tests on the electronics will be performed by illuminating in single photon mode uniformly the Focal Surface or the first lens by a LED-controlled as described in~ \cite{bib:Calib}.
     177At the end of  the integration and at launch site, basic health tests on the electronics will be performed by illuminating uniformly directly the Focal Surface or the first lens by a LED-controlled, in single photon mode, 
     178as described in~ \cite{bib:Calib}.
    170179
    171180
     
    174183During the balloon flight operation, the instrument will be controlled from ground by an operator using a control program~\cite{bib:OffOnLineAna} interfaced to the TC/TM system (Telecommand and Telemetry) NOSYCA of CNES.
    175184At a given altitude reached by the balloon, a command will be issued to turn on the instrument. The HK system will turn on one by one each of the subsystems while the monitoring parameter will be downloaded at ground.
    176 When every parameters looks perfect, the balloon operator can launch the DAQ program running on the CPU. He will control basic run parameters, namely the background rate calculated by the PDMB. Conventionally the thresholds auto-adapt to the required L1-L2 rates unless the operator forces another mode of trigger settings. At any moment, the operator can shut down the instrument. This will be done when the balloon descent will be activated.
    177 
     185When every parameters looks perfect, after having chosen the convenient configuration parameters for the ASICs and the Triggers, the balloon operator can launch the DAQ program running on the CPU. He will control basic run parameters, namely the background rate calculated by the PDMB. Conventionally the thresholds auto-adapt to the required L1-L2 rates unless the operator forces another mode of trigger settings. At any moment, the operator can shut down the instrument. This will be done when the balloon descent will be activated.
     186
     187\section{Conclusion}
     188\label{sec:Conclusion}
     189A reduced scaled version of the future space telescope JEM-EUSO, but with similar instrumentation, is being built to serve as a pathfinder embarked in the gondola of a stratospheric balloon. EUSO-Balloon is by itself a complete autonomous instrument capable to perform the same kinds of measurements as JEM-EUSO, namely the photo detection, the analog and digital electronics involving the signal measurements, digitisation and the trigger, implemented in the developed ASICs and FPGA. Also, a Data Processing system has been developed including the data acquisition and the instrument monitoring. This telescope will be operational for CNES balloon campaigns next year.
    178190
    179191\vspace*{0.5cm}
    180 \footnotesize{{\bf Acknowledgment:}{ This work was technically and financially supported  by \mbox{CNES} and the JEM-EUSO collaboration.
     192\footnotesize{{\bf Acknowledgment:}{ This work was strongly, technically as well as financially supported  by \mbox{CNES} and the JEM-EUSO collaboration.
    181193}
    182194
     
    187199\bibitem{bib:EBSimulation} T. Mernik \textit{et al.} ESAF-Simulation of the EUSO-Balloon, this proceedings, paper 875,
    188200\bibitem{bib:Optics} Manufacturing of the TA-EUSO and EUSO-Balloon lenses, this proceedings, paper 1040,
    189 \bibitem{bib:FrontEndEl}P. Barrillon \textit{et al.}, The Front-End Electronics of the EUSO-Balloon UV camera,this proceedings, paper 765,
     201\bibitem{bib:FrontEndEl}P. Barrillon \textit{et al.}, The Electronics of the EUSO-Balloon UV camera,this proceedings, paper 765,
    190202\bibitem{bib:ASIC} H. Miyamoto \textit{et al.}, Performance of the SPACIROC front-end ASIC for JEM-EUSO, this proceedings, paper 1089,
    191203\bibitem{bib:CCB} J. Bayer \textit{et al.}, Second level trigger and Cluster Control Board for the JEM-EUSO mission,this proceedings, paper 432,
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