# LAV contribution to the NA62 trigger Mauro Raggi, LNF ONLINE WG CERN 9/2/2011.

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LAV contribution to the NA62 trigger Mauro Raggi, LNF ONLINE WG CERN 9/2/2011

LAV in the L0 or L1 trigger? 1.LAV can help rejecting photons from     decay and  2.LAV can provide Time (Dt 500ps), Energy (20%),  position 3.The LAV detector is able to provide all its information directly @ L0TP 4.The LAV it’s able to send all it’s data to L1 PCs following L0TP request We have the possibility to choose in which trigger level we use the LAV information

Why the LAV in LVL0?

LAV MIP primitives to L0 Identify MIPs ( μ or π ) and to distinguish them from photons and electrons: Identify MIPs ( μ or π ) and to distinguish them from photons and electrons: N blocks per ring ≤ 2 for each involved ring N blocks per ring ≤ 2 for each involved ring 3 ≤ N firing blocks ≤ 6 3 ≤ N firing blocks ≤ 6 E_bl < 200 MeV for each block over threshold E_bl < 200 MeV for each block over threshold E_ring(i) /E_ring(i+1) < 2 for each pair of rings E_ring(i) /E_ring(i+1) < 2 for each pair of rings N_cl = 1, one cluster (only) in the LAV station N_cl = 1, one cluster (only) in the LAV station The LAV MIP trigger can be matched with a MUV hit to distinguish pions from muons The LAV MIP trigger can be matched with a MUV hit to distinguish pions from muons

LAV MIP efficiency test beam MIP single block efficiency of the LAV is >95% at the foreseen thr 7mV We will have >3 blocks per MIP in each LAV so the efficiency will rise well above 99% Can LAV12 be used, in absence of the CHOD, to compensate the geometrical inefficiency of MUV in covering the RICH triggered muons? L0 algorithm efficiency to be studied!

EM showers trigger Not necessary very efficient for very low energy particles @ L0? Not necessary very efficient for very low energy particles @ L0? All conditions can be used in or or and All conditions can be used in or or and Ntot > 10 OR Etot > 1 GeV Ntot > 10 OR Etot > 1 GeV Ering > 0.1 GeV x Nring for al least 2 rings Ering > 0.1 GeV x Nring for al least 2 rings E_ring(i) /E_ring(i+1)> 2 for at least a pair of rings E_ring(i) /E_ring(i+1)> 2 for at least a pair of rings The real algorithm will be tuned using the LAV MC for L0 The real algorithm will be tuned using the LAV MC for L0 Purity for low energy photon is an issue Purity for low energy photon is an issue

MC multiplicity MIP showers Muon 1 GeV Electron 1 GeV Not trivial to distinguish low energy photons form muons P. Massarotti form LAV MC

ANTI-A12 Producing the L0 LAV STEP I STEP I: only ANTI-A12 in L0: Compute only ANTI-12 primitives and send to L0TP Receive the L0TP response and send all hits to L1 PCs Reconstruct the whole detector information in PCs

Producing the L0 LAV STEP I Advantages of having only ANTI-A12 in the L0 Advantages of having only ANTI-A12 in the L0 Only needs firmware development Only needs firmware development The algorithm only involves 1 ANTI The algorithm only involves 1 ANTI Don’t require TEL62 communication & LAV data condensation Don’t require TEL62 communication & LAV data condensation Save a lot of man power (good for the synchronization or early run) Save a lot of man power (good for the synchronization or early run) Disadvantages Disadvantages Lose ~ 50% of LAV rejection capability in L0 Lose ~ 50% of LAV rejection capability in L0 Lose some muon discrimination capability Lose some muon discrimination capability All the rejection is recovered in L1 All the rejection is recovered in L1

Producing the L0 LAV STEP II

What we need for step II Scenario n 2 all the 12 LAV directly in LvL0 (as in the TDR) Scenario n 2 all the 12 LAV directly in LvL0 (as in the TDR) Compute local primitives into single ANTI and send to concentrator Compute local primitives into single ANTI and send to concentrator Condensate all the 12 station’s primitives into a LAV primitive Condensate all the 12 station’s primitives into a LAV primitive Send the LAV primitive to L0TP and receive the response Send the LAV primitive to L0TP and receive the response Distribute the L0TP response to all the LAV’s TEL62 Distribute the L0TP response to all the LAV’s TEL62 All the TEL62 send the data to L1 PC’s using remaining eth interface All the TEL62 send the data to L1 PC’s using remaining eth interface Advantages Advantages Full LAV rejection capability @L0 (50% better rejection     ) Full LAV rejection capability @L0 (50% better rejection     ) No need of having the LAV in the L1 trigger (only integrity checks) No need of having the LAV in the L1 trigger (only integrity checks) Disadvantages Disadvantages Need to project and build 4Gbit Eth receiver for TEL62 mezzanine Need to project and build 4Gbit Eth receiver for TEL62 mezzanine Can a commercial 24x1Gbit Eth switch be enough? Can a commercial 24x1Gbit Eth switch be enough? Need 1 more dedicated TEL62 Need 1 more dedicated TEL62 Need to develop a dedicated firmware for the concentrator TEL62 Need to develop a dedicated firmware for the concentrator TEL62

Conclusions LAV is able to send all it’s raw hits to LvL1 LAV is able to send all it’s raw hits to LvL1 Care should be taken to noisy channels Care should be taken to noisy channels The LAV can produce 2 primitives @ L0 The LAV can produce 2 primitives @ L0 MIP primitive (  or  ) order 99% efficiency MIP primitive (  or  ) order 99% efficiency Shower primitive (e or  ) low E purity to be understood Shower primitive (e or  ) low E purity to be understood LAV can have 2 approach to trigger LAV can have 2 approach to trigger Participate to L0 with only ANTI-A12 50% rejection Participate to L0 with only ANTI-A12 50% rejection o Exploit the rest of the rejection at L1 Use the full detector directly at L0 (all 12 stations) Use the full detector directly at L0 (all 12 stations) o The data load seems feasible o The computing required in the TEL62 has to be understood

NA62 trigger rates overview At which level is the LAV system able to send data? How many data will it send?

LAV expected raw rates TDR In principle the TEL62 is able to transmit all the hits of the LAV using 3 Gbit eth interface leaving 1 free for the trigger. From TDR Using an hit size of 192 bits and only 7 hits per event (MIP)

Simulation of LAV rejection factors What is already done from Spasimir it’s more or less all What is already done from Spasimir it’s more or less all Assume that the LAV is efficient for all the impinging photons is a good approximation @ trigger level Assume that the LAV is efficient for all the impinging photons is a good approximation @ trigger level The only upgrade could be to implement a thr at 50 MeV below which the detector is inefficient The only upgrade could be to implement a thr at 50 MeV below which the detector is inefficient Try to understand the L0 LAV algorithm efficiency for low energy gamma. Try to understand the L0 LAV algorithm efficiency for low energy gamma.

LAV maximum data volume revised Raw LAV rate computed assuming: 15 hits/station and 160bits per hit (included extra hits in the TDC) Due to the fact that the rate is MIP dominated we have more than a factor 2 safety factor (expected hits per MIP ~7 hits/station) * Assumes the station has data to send to LVL1 for each LVL0 request (pessimistic) ** Assumes 50% of the stations will respond to each LVL0 request (pessimistic) LAV system should be able to send all its data, without any reduction, to LvL1 following a LvL0 request!

Hit size Each hit will produce 4 of this word Each hit will produce 4 of this word 2x32bit leading + 2x32bit trailing 2x32bit leading + 2x32bit trailing Assuming to add a 32 bits time stamp to the hit Assuming to add a 32 bits time stamp to the hit Total hit size is 160bits Total hit size is 160bits

Maximum latency in TEL62 DDR Assuming the highest rate ANTI-A1 1.77MHz Assuming the highest rate ANTI-A1 1.77MHz Assuming a factor 2 more hit 15/stat (refirings) Assuming a factor 2 more hit 15/stat (refirings) Total size of data produced by a single ANTI: Total size of data produced by a single ANTI: 15hits*160bit*2MHz = 4.8 Gbit/s 15hits*160bit*2MHz = 4.8 Gbit/s 600 Mbyte/s into TEL62 memories 600 Mbyte/s into TEL62 memories TEL62 has 2Gbyte or 4Gbyte DDR memories TEL62 has 2Gbyte or 4Gbyte DDR memories 2Gbyte means ~ 3.3 s ANTI data 2Gbyte means ~ 3.3 s ANTI data 4Gbyte means ~ 6.6 s ANTI data 4Gbyte means ~ 6.6 s ANTI data

Data load to the concentrator The concentrator will receive the primitives from the LAV stations with following information The concentrator will receive the primitives from the LAV stations with following information Trig. type (muon or gamma) Trig. type (muon or gamma) Event time (Fine time + time stamp) 40 bits Event time (Fine time + time stamp) 40 bits Event Energy (most probably charge) Event Energy (most probably charge) Event position (phi position of the seed in the LAV station) Event position (phi position of the seed in the LAV station) Ev. typeEv. Energy Ev. Position Assuming as rate the LAV total rate of 11MHz and data size 64bit – Total data load to concentrator= 11MHz*64bit = 704 Mbit/s – The rate divided over 12Gbit eth can be managed by 1 TEL62

Data load from concentrator to L0TP For each local primitive the concentrator should send 2x32bit word to L0TP shown above: Data to L0TP=2x32x4.5E6 = 288 Mbit/s = 36MByte/s using the LAV OR rate 4.5MHz Data to L0TP=2x32x11.5E6= 740 Mbit/s = 93MByte/s using the LAV tot rate 11.5MHz The concentrator task is to condensate the 12 station information in a single primitive message to L0TP The concentrator should reduce the total LAV rate 11MHz to the LAV OR rate of 4.5 MHz

Reducing the data volume @ LVL1 Reduce the number of extra hits Reduce the number of extra hits Define in the FPGA an algorithm which suppress extra hit in the same TDC channel Define in the FPGA an algorithm which suppress extra hit in the same TDC channel Reduce the size of the hit information Reduce the size of the hit information Transmit only hit charge and time. Transmit only hit charge and time. Condensate the LAV information Condensate the LAV information Provide particle based info instead of hits Provide particle based info instead of hits

Transmit only charge and time HPTDC produces 4x32 bits word per hit HPTDC produces 4x32 bits word per hit 2x32bit leading and 2x32bit trailing edge 2x32bit leading and 2x32bit trailing edge 32bit time stamp 32bit time stamp 160bit per hit 160bit per hit If compute a time and charge in the TEL62 or @ L1 If compute a time and charge in the TEL62 or @ L1 1x12 bit charge + 1x8bit fine time + 12 bit channel 1x12 bit charge + 1x8bit fine time + 12 bit channel 1x32 bit time stamp 1x32 bit time stamp 64 bit per hit 64 bit per hit Can gain more than a factor of 2 in hit size! Can gain more than a factor of 2 in hit size!

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