Changeset 170 in JEM-EUSO for ICRC2013/EusoBalloonDetector/trunk/icrc2013-EBDet-morettodagoret.tex

Timestamp:

Jun 3, 2013, 6:59:21 PM (11 years ago)

Author:

moretto

Message:

version du 3 juin après corrections de Marco Ricci

File:

• ICRC2013/EusoBalloonDetector/trunk/icrc2013-EBDet-morettodagoret.tex (modified) (7 diffs)

ICRC2013/EusoBalloonDetector/trunk/icrc2013-EBDet-morettodagoret.tex

@@ -6 +6 @@
 
 \usepackage{icrc2013}
+\usepackage[english]{babel}
 
 %\usepackage{amsfont}
@@ -59 +60 @@
 \keywords{JEM-EUSO, UHECR, space instrument, balloon experiment, instrumentation}
 
-\hyphenation{con-di-tions de-vo-ted a-node per-form a-nodes mi-cro-se-cond practi-cally ge-ne-ra-ting in-te-gra-ting vol-ta-ge pi-xels re-la-ti-ve-ly mo-del im-po-sing no-mi-nal o-pe-rates sli-ghtly li-mit fi-gu-re ASICs PDMB CCB pho-to-ca-thode reads Pro-ces-sing con-ver-ters its ca-me-ra o-pe-ra-tors}
+%\hyphenation{con-di-tions de-vo-ted a-node per-form a-nodes mi-cro-se-cond practi-cally ge-ne-ra-ting in-te-gra-ting vol-ta-ge pi-xels re-la-ti-ve-ly mo-del im-po-sing no-mi-nal o-pe-rates sli-ghtly li-mit fi-gu-re ASICs PDMB CCB pho-to-ca-thode reads Pro-ces-sing con-ver-ters its ca-me-ra o-pe-ra-tors}
 
 \begin{document}
@@ -103 +104 @@
 The mechanics of the instrument is made of Fibrelam\textregistered \ panels, arranged together through fiberglass sections.
 The instrument is coated by an insulating cover to protect the components from fast temperature changes during balloon ascent and descent.
-Special 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. The bottom part is therefore equipped with crash-pads, which absorb strong 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.
+Special 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. The bottom part is therefore equipped with crash-pads, which absorb strong 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.
 The instrument booth, 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 side is an aluminium radiator used to dissipate the heat generated by the electronics. The instrument is surrounded by buoys to avoid sinking in case of splashdown and to raise straight up the instrument booth above the water level.
 
@@ -110 +111 @@
 The main instrument is divided into the following main subsystems: 1) the Optics; 2) The Focal Surface (FS) which includes
 the photodetector with the MAPMTs, the ASICs measuring signals, the Photo-Detector Module Board (PDMB) and the High Voltage Power Supplies (HVPS); 3) The Data Processing (DP) involving the Cluster Control Board (CCB) providing readout triggers and the Data Acquisition System (DAQ); 4) Utilities like the monitoring also called the housekeeping board (HK) and the low voltages power supplies (LVPS) associated to the batteries (PWP).
-All those subsystems are all described below.
+All these subsystems are all described below.
 
 \subsection{Optics Subsystem}
@@ -120 +121 @@
 
 \vspace*{-0.3cm}
-\paragraph{MAPMTs} They are Hamamatsu photon detectors (R11265-M64) 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 photons per $\mu$s when working at their nominal high gain of $10^6$. The anode signal of the MAPMTs are measured and digitised by the ASICs and managed by an FPGA based PDM board, which performs also the first level trigger selection. More details on the PDM can be found in~\cite{bib:FrontEndEl}.
+\paragraph{MAPMTs} They are Hamamatsu photon detectors (R11265-M64) 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 photons per $\mu$s when working at their nominal high gain of $10^6$. The anode signals of the MAPMTs are measured and digitised by the ASICs and managed by an FPGA based PDM board, which performs also the first level trigger selection. More details on the PDM can be found in~\cite{bib:FrontEndEl}.
 
 \vspace*{-0.3cm}
@@ -127 +128 @@
 %{\bf (IS THIS AN ABSOLUTE VALUE OR A FACTOR?)}. 
 Fast switches (SW) responsive at $\mu$s time-scale, adapt the voltage values to tune the MAPMT gain according to the intensity of photon flux. 
-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 voltage. The switching decision logic is implemented in the \mbox{FPGA}, which reads 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.
+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 voltage. The switching decision logic is implemented in the \mbox{FPGA}, which reads out the \mbox{ASICs}. In the PDM, there are 9 independent CW with their individual 9 SW, assembled into two separated HVPS boxes, each CW controlling independently the 9 ECs high voltages.
 
 \vspace*{-0.3cm}
@@ -143 +144 @@
 The DP includes the CCB designed to perform the second level trigger L2, described in~\cite{bib:CCB}. For each generated L1 trigger, the CCB reads data corresponding to the 128 consecutive GTU from the PDMB buffer. 
 %{\bf(I AM NOT SURE ABOUT THE BUFFER!)}. 
-In JEM-EUSO, the CCB combines information from 9 PDMs, to reduce the trigger rate to about a few Hz or less compatibly with the data storage capabilities of the DAQ. In the case of the EUSO-Balloon, the CCB, based on a Xilinx Virtex-4 FX-60, serves only one PDM and therefore the L2 trigger is not essential. However the L2 functionality will be tested. In addition to perform the second trigger stage, the CCB reads events from PDMB and pass them to the CPU. It also passes clock signals and configuration data to the PDM. The Clock-Board (CLKB), based on a Xilinks Virtex5 FPGA is part of the DP. It generates and distributes the system clock (40 MHz) and the GTU clock (400 kHz, 98\% duty cycle) to all devices. A GPS-Board provides information to perform event time tagging data with an accuracy of a few microseconds. The 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. This implies a data flow of 3MB/s for a 10 Hz L1-L2 trigger. The CPU writes all data on disks (1 TB CZ Octane SATA II 2.5Ó SSD) and may also send to the balloon telemetry a subset of events flagged by the CCB, to allow monitoring.
+In JEM-EUSO, the CCB combines information from 9 PDMs, to reduce the trigger rate to about a few Hz or less compatibly with the data storage capabilities of the DAQ. In the case of the EUSO-Balloon, the CCB, based on a Xilinx Virtex-4 FX-60, serves only one PDM and therefore the L2 trigger is not essential. However the L2 functionality will be tested. In addition to perform the second trigger stage, the CCB reads events from PDMB and passes them to the CPU. It also passes clock signals and configuration data to the PDM. The Clock-Board (CLKB), based on a Xilinks Virtex5 FPGA is part of the DP. It generates and distributes the system clock (40 MHz) and the GTU clock (400 kHz, 98\% duty cycle) to all devices. A GPS-Board provides information to perform event time tagging data with an accuracy of a few microseconds. The 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. This implies a data flow of 3MB/s for a 10 Hz L1-L2 trigger. The CPU writes all data on disks (1 TB CZ Octane SATA II 2.5Ó SSD) and may also send to the balloon telemetry a subset of events flagged by the CCB, to allow monitoring.
 
 \vspace*{-0.3cm}
 \paragraph{Monitoring}
-The instrument behaviour is controlled at low frequency by the Housekeeping system (HK) which is a part of the 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. The 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.
+The instrument behaviour is controlled at low frequency by the Housekeeping system (HK) which is a part of the 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 polls from time to time the alarms and initiates the corresponding foreseen actions. The 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.
 
 \vspace*{-0.3cm}