Amsterdam 29 March 2011 Fernando Urbano IFIC (CSIC – Universidad de Valencia) KM3NeT Optical Calibration Laser Beacon and Nanobeacon Status

KM3NeT TIME CALIBRATION PROPOSAL (Reminder) Decoupling within the same D.U. (intra- D.U.) and between D.U. (inter-D.U.) calibration systems INTRA D.U. Calibration : Two Nanobeacon per DOM. Looking upwards and downwards - Less expensive and high redundancy - Either external or internal trigger - Frequency of several kHz depending on the DAQ system (300 ANTARES) - Avoid cumbersome synchronization process, only one LED per Nanobeacon

INTER D.U. Calibration : Laser 532 nm - Higher in intensity and shorter pulses < 1 ns - No synchronization needed - More expensive but less redundancy required - Tunable by Liquid Crystal Optical attenuator - Collimated beam -> Diffusion device needed Decoupling within the same D.U. (intra- D.U.) and between D.U. (inter-D.U.) calibration systems INTRA D.U. Calibration : Two Nanobeacon per DOM. Looking upwards and downwards - Less expensive and high redundancy - Either external or internal trigger - Frequency of several kHz depending on the DAQ system (300 ANTARES) - Avoid cumbersome synchronization process, only one LED per Nanobeacon 3 KM3NeT TIME CALIBRATION PROPOSAL (Reminder)

NANOBEACON STATUS - ELECTRONICS Two electronic components: Pulser: It contains and flashes the LED with the control boards commands Control Board: Selects the LED Light intensity Selects the trigger (external or internally generated in the control board) Provides a trigger signal to the pulser Selects the frequency of the generated trigger. To be fixed depends on the DAQ. 10 KHz possible? Several improvements performed: The Nanobeacon Control Board can work either at 5 V or 3.3 V The external trigger signal now is LVDS The trigger selection, between internal or external trigger, has been improved and the jitter has been substantially reduced (From µs to ns) 4

NANOBEACON STATUS - ELECTRONICS INPUTSOUTPUTS 5

NANOBEACON STATUS - PPM 6 The Nanobeacon will be included in 4 of the DOM allocated in the 2 active storeys of the PPM (Storey 20 and 19). Nanobeacons of storey 20 will look horizontally to the other DOM in the same storey.

NANOBEACON – PPM OPENING ANGLE 40m 3 m A 15°opening angle is sufficient to illuminate OMs above the beacon even in perpendicular arrangement including potential misalignment

NANOBEACON STATUS - PPM 8 Regarding the Nanobeacons it would be better to have the second active storey in position 17 instead of 19. If possible this option is recommended by us. BEST OPTION FOR NANOBEACON TEST

NANOBEACON – PPM PLANNING 9 PLANNING Specifications 05/04/2011 Interface definition with CLB 05/04/2011 LED Pulser and Control board Study – already done Schematic and layout 05/04/2011 purchase/manufacture 25/04/2011 Tests 13/05/2011 Ready for integration 20/05/2011

NANOBEACON STATUS – NEMO TOWER PHASE 2 10 The installation of some Nanobeacons on the NEMO Tower to be deployed this summer at Capo Pasero has been approved by the NEMO Technical board. Work to adapt the Nanobeacon, mechanically and electronically, to the Nemo Experiment are under way. The final number of Nanobeacon is not decided yet.

NANOBEACON STATUS – NEMO TOWER PHASE 2 Nanobeacon mechanics (ONLY FOR NEMO): Two pieces in PVC: 1.- Glued to the glass sphere (fixed) 2.- Screwed (in) to the first one: Holds the LED + Electronics Protects the PMT from the Nano-Beacon light Easy to be replaced

NANOBEACON STATUS – NEMO TOWER PHASE 2 MECHANICAL SUPPORT PULSER CONTROL BOARD

LASER BEACON – COMPONENTS Titanium Container Attenuator LASER Anti-Biofuling System Slow Control Inteface Photodiode Signal Connector

LASER BEACON -CONTAINER 14 Density (×1000 kg/m 3 ) 4.43 Poisson's Ratio0.342 Elastic Modulus (GPa) Cylinder of 542 mm long, with a diameter of 142 mm that holds the laser, the liquid crystal optical attenuator and the electronics. It is made of Titanium grade 5 (Ti6Al4V)

LASER BEACON – NEMO PHASE 2 One laser is going to be deployed in NEMO PHASE 2 A complete different electronics has been developed as:  Only RS-232 connection available  There is a power limitation: mA which has been overcome with a battery system  Read-out of the internal photodiode removed for simplicity The laser is a STG-03E-1S0 from Teemphotonics which emits light with a wavelength of 532 nm after frequency doubling of the original Nd-YAG wavelength of 1064 nm. 15 Pulse Width (ps)400 Energy / Pulse (μJ)3.5 Peak Power (kW)10 Repetition rate (kHz) Average Power (mW)≤ 7

LASER BEACON – KM3NeT A more powerful laser is under study. Selected model PNG-B02010 A different container will be probably needed Completelly different electronics from the Nemo one. Photodiode signal read-out really important Also research with blue lasers is ongoing. 16

Conclusions INTRA DU Calibration. Nanobeacon 4 Nanobeacons on 2 Active Storeys of the PPM Several Nanobeacons on the NEMO Phase 2 Last design: supply, LVDS trigger and jitter signal improved Final frequency range depens on the DAQ INTER DU Calibration. Laser beacon Laser Beacon ready to be integrated in NEMO Phase 2 Looking for a more powerful green and blue lasers for KM3NeT New design of electronics and Titanium container will be needed 17

TIME CALIBRATION PROPOSAL THANKS FOR YOUR ATTENTION! 18

KM3NeT LASER STUDIES - SPECTRUM Measurements carried out with the Spectrometer Ocean Optics HR4000 Both Lasers of Teemphotonics, present the main spectrum at 532 nm as expected 19

KM3NeT LASER STUDIES - SPECTRUM  Measurements of an ALPHALAS, GmbH blue laser  Present nm, 808 nm and 945 nm  The undesired emission peaks must be filtered out: 20

LASER STABILITY The 532 nm are quite stable The 485 nm is not so stable More tests are under progress to determine is the instability is due to the 485 nm emission or to the infrared 808 nm and 945 nm 21