Survey
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Download Timing Calibration in NEMO
Document related concepts
no text concepts found
Transcript
Timing calibration in NEMO M. Circella Istituto Nazionale di Fisica Nucleare, Bari on behalf of the NEMO Collaboration M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 NEMO Telescope layout 200 m Tower 200 m • 1 primary Junction Box • 8 secondary Junction Boxes Secondary JB • 64 towers • 200 m grid pitch Primary JB 1400 m • 64 PMT on each tower • 4096 PMT in total Electro-optical cable to shore: • 48 optical fibres • 3 – 4 conductors M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Tower Layout FCM (Floor Control Module) 19.44 Mbps Optical Module PMT64 20m PMT63 Floor 16 40m Floor 15 40m Floor 14 SDH STM-1 (155 Mbps) Floor 2 PMT4 DWDM communications Floor 1 (2.5 Gbps) Junction Box PMT1 PMT3 40m PMT2 150m DWDM mux M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Front-end electronics (inside the Optical Modules) Log. Compr. ADC 8bit PMT [100MHz] FIFO [100MHz] FCM interface clk off1 off2 com ADC 8bit FPGA DOUT DOUT Soft trigger Vcc To FCM clk 19.44 Mbps [email protected] Counter From FCM 432 kbps Offset & Gain Lock In PLLout Cal. Sensors 8 F C M DSP Full description of the NEMO Front-End electronics in Domenico Lo Presti’s and Carlo Nicolau’s Out ADC\DAC 10bit presentations tomorrow (A2.4.1 and A2.4.3) JTAG In [Slow control] SCI Flash 256kX8 M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Proprietary Protocol (Electric) Rx: 19.44 Mbps Tx: 432 kbps Floor Control Module SDH mapper (Transwitch Fast-3N) Power Conditioning OM1 OM2 clock FPGA OM3 OM4 Sinchronous Serial (SPI) E/O/E interface (Finisar FTR-1631) TBTI STM-1 Interface Tower Base Overhead STM-1 Protocol (optic fibre) 155 Mbps Slow Full description of the NEMO SDH transport in Control Fabrizio Ameli’sDSP presentation later (A1.4.9) STM-1 Interface Control PCI Bandwidth: 120 MBps, enough to allow real-time transmission to Host of STM-1 protocol data Circuits Indipendent Bidirectional Communication between DSP and STM-1 Interface through TOH channels (E1, E2, F1, DCC) PCI Bus M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 STM-1 Payload M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 SDH STM-1 data frame 270 bytes 9 rows 9 bytes M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 261 bytes (DWDM) DATA TRANSPORT in NEMO from tower to shore 1/16 DWDM MUX 1/16 DWDM DEMUX Tower from shore to tower 1/16 DWDM DEMUX Floor #1 Tower #1 Floor # 16 1/16 DWDM MUX Floor #1 Tower #1 Floor # 16 Shore One colour per floor (50 GHz spacing) M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Time measurements in NEMO 1. The signals from the Optical Modules are continuously sampled at 200 MHz (by means of two ‘staggered’ ADC’s) 2. When a threshold value (remotely programmable through slow control) is met, the over-threshold samples, plus a fixed number of pre-trigger samples, are stored in a FIFO for transmission to shore 3. The readout at the trigger time of a 16-bit 100 MHz counter is stored together with the sampled signals Synchronization in NEMO 1. The clock signal is recovered offshore (in each Floor Control Module) from the SDH frames received from the onshore station 2. The SDH mapper inside the FCM recovers a low-jitter 19.44 MHz clock (also used to clock out the ‘payload’ data received in the SDH data frames) 3. A 1.215 MHz clock is delivered from the FCM to the Optical Modules 4. This 1.215 MHz clock is fed to a PLL to give rise to the 100 MHz clock used for all front-end operations M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Timing calibration in NEMO Two different problems: • Compare the time measured in the apparatus with UTC time (“absolute” timing calibration) Same problem for all neutrino telescopes • Determine the offsets in local time measurements (“relative” timing calibration), i.e. the propagation time of commands and clock signals from onshore to offshore Same problem for all neutrino telescopes if the digitization and time measurements are performed offshore M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Time calibration in NEMO (the approach) I. SDH “echo” calibration PMT64 20m PMT63 Floor 16 Floor Control Module 40m Floor 15 II. Optical calibration 40m Floor 14 Optical Module (& FE electronics) Floor 2 PMT4 III. Shore station: It will be equipped for the SDH “echo” time measurements and with GPS PMT3 40m Floor 1 PMT1 PMT2 150m Tower JB Secondary JB M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 The FCM interface to the timing calibration system OM1 Power Conditioning OM2 OM3 OM4 clock FPGA TBTI STM-1 Interface Overhead Slow DSP Control The FPGA will sinchronously: • Deliver the reset signal to the time counters in the optical modules • Deliver an echo signal to the shore station • Activate the optical calibration system in response to a shore command PCI Bus M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Tower Base Optical beacons are ineffective for km3-scale detectors! Number of photoelectrons Distance of a PMT from the optical source M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Optical calibration system Optical Module diffuser Optical fibre splitter Attenuator Optical source (+ time stamp) Photodiode FCM (Floor Control Module) FCM electronics interface M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003 Timing calibration in NEMO: conclusions and perspectives The relative timing calibration will be performed by means of a SDH “echo” measurement and an optical calibration system Interface with the data trasport system under definition Different choices under study for the optical calibration system M. Circella and the NEMO Coll., Timing Calibration in NEMO VLVT workshop, Amsterdam, October 2003
Related documents