1. LAV trigger primitives Francesco Gonnella Photon-Veto Working Group CERN – 09/12/2014

2. LAV primitives working principles LAV12  256 lead-glass blocks  2 threshold for each block: 512 channels into one TEL62 PP firmware  Seeks coincidences (~6 ns programmable) between high and low threshold  Coincidence => slewing correction, primitive production  Possibility of asking a trailing on high and/or threshold crossing and a minimum ToT value to produce a primitive  No coincidence => discard the hit SL Firmware  Sorts and merges hits  Merges any hits within up to 25 ns (programmable)  Outputs the L0 primitives 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati2

3. What to do with trigger primitives?  Trigger primitives are triggerless data coming from LAV12  Data must be very simple: hit time (40bit LSB=100ps) and primitive ID  Primitive ID represents the number of hits in the primitive cluster  4 programmable thresholds define the number of hits e.g.:  ID 0x11 -> less than 2 hits (i.e. one hit)  ID 0x12 -> less than 4 hits  ID 0x13 -> less than 10 hits  ID 0x14 -> more than 10 hits  With minimal effort, data may be collected from all LAV stations  Beam monitoring  The “famous” 100Hz structure of the beam was observed for the first time in LAV trigger primitives  Digital L0 Trigger 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati3

4. LAV firmware on CHOD  The LAVFEE board used for CHOD provides 8 analogue sums, on for each quadrant (H and V)  8 channels are connected to an independent TDC board, again through a LAVFEE board:  4 sums of horizontal quadrants  4 sums of vertical quadrants  LAV firmware is adapted to look for coincidences between corresponding horizontal and vertical quadrants  This is done connecting the Vertical Quadrant as “low threshold” and the Horizontal Quadrant as “high threshold”  Horizontal-Quadrant signals were artificially delayed to assure that they come after the vertical ones 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati4

5. Beam monitoring 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati5  Primitive Ethernet cable are connected from LAV12, MUV3, and CHOD to Torino L0TP  Thanks to three Ethernet switches primitive data are duplicated and are sent to a pc in the EB  Primitives are acquired and raw data are stored  The PC can receive primitives from any detector connected to the NA62 network  A program has been developed to decode raw primitive data.  An online monitor software is used to produce histograms  These histograms are periodically sent to beam experts in order to study the fine structure of the beam. MUV3 LAV CHOD

6. Burst profile 25ns 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati6

7. Fine time burst structure 25ns 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati7 ~10 ms

8. Initial spike 25ns 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati8

9. LAV-CHOD comparison 25ns 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati9 LAV CHOD

10. LAV-CHOD burst fine-structure 25ns 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati10 LAV CHOD

11. Fine structure average ~30 bursts 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati11  The burst fine-structure looks somehow coherent among different bursts…

12. Conclusions  Trigger primitives were never used for trigger generation during this run  A lot of debug has been performed and now LAV firmware is quite reliable  Nevertheless LAV rpimitives have been very useful for the beam monitoring to spot the beam fine structure (NA62 readout is not designed to cope with such an instantaneous rate at nominal intensity)  We have just started a series of tests of trigger generation with primitives (without beam)  First results were obtained yesterday evening and they seem to be promising  During the last days of the run, trigger generation with LAV primitives will be tested with L0TPs (Ferrara and Torino) 09/12/2014Francesco Gonnella - Laboratori Nazionali di Frascati12

13. Thanks for your attention francesco.gonnella@lnf.infn.it 09/12/2014 13 Francesco Gonnella - Laboratori Nazionali di Frascati