NewCHOD Firmware Chris Parkinson, University of Birmingham 16 th December 2015 1

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NewCHOD Firmware

Chris Parkinson, University of Birmingham

16th December 2015

Outline

Chris Parkinson NewCHOD Firmware 16th December 2015

• Environment of the NewCHOD

• Adapting the MUV3 firmware for the NewCHOD

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The NewCHOD


• NewCHOD is separated into four quadrants• Each quad has 38 slabs, each read out on two channels• 38 * 2 * 4 = 304

– MUV3 has 288 (296) channels• ‘high’ and ‘low’ channel numbers

for each slab like in MUV3

• Analogue→digital signals usingsame NewCFD boards (same as MUV 3)

• Coincidence between channelsto be made at firmware level

• GREEN – inner pads• RED – pinn veto region

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NewCHOD rates


• Four inner tiles (red) take the most rate: about 1MHz – Compare to 3.2MHz of MUV 3 tile 147

• 304 channels fit comfortably into1xTEL62 board and 3xTDCB

• Alternative:Use 4xTDCB so that each TDCBcorresponds to a single quadrant

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NewCHOD rates


• Based on Evgueni’s calculations, see LINK, which assume nominal and stable intensity during the burst

• Rate sum over NewCHOD tiles = 45 MHz (15MHz in MUV 3)– This is much larger than the 10MHz particle rate due to photon showers.– Divide by number of PP: 15 MHz (3PP) or 11.25 Mhz (4PP) (5 MHz in MUV 3)– Can removing trailing words help? (implication: fifos in PP fill up quicker,

might need to be larger)• 3x increase in PP→SL communication w.r.t MUV 3

1. Faster (simpler) clustering in the SL (reads faster)2. “Single-word” hits sent from PP→SL (about 2x less data)

• Once in the SL, the clustering will reduce the rate from 45MHz down to the nominal 10MHz particle rate (13.2 MHz in MUV3)– Only difference in the clustering is that it will form larger clusters.

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https://indico.cern.ch/event/471254/contribution/6/attachments/1205551/1756592/evgueni_161215.pdf

NewCHOD primitives


• For the NewCHOD there are two types of primitive (1-track, multi-track)

• Multi-track primitives:1. C3 – simply the number of hits merged into a single primitive during the

clustering. Cluster holds two bits to store the hit count.2. Qx – if using four TDCBs, then the SL can determine the quadrant of each

hit since it knows the input buffer. With three TDCBs, the quadrant must be passed into the system via the PPs (two bits needed, simple extension of the inner/outer pads). Each cluster must hold four bits corresponding to each quadrant. A 1X1X or X1X1 mask generates the Qx condition.

3. TB – same as Qx, but a different mask.4. 100N+1 veto – do not send primitive if one of the inner pads was hit.

Cluster must hold a ‘veto’ bit. Inner/outer pads sent via usual MUV3 system.

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NewCHOD primitives


• For the NewCHOD there are two types of primitive (1-track, multi-track)

• primitives:1. ‘pinn veto’ (PV) region – clusters must hold one bit to determine whether

all hits in the cluster belong to slabs in the PV reigon. If *all* hits were within the PV region, do not send the primitive. The slabs must be identified as ‘PV’ or not by sending one bit through the PP, in the same way as the inner/outer pads.

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Final primitives


• A given cluster(primitive) can pass either the or multi-track selection. The primitive is sent if *either* of the selections is passed. Which selection was passed must be encoded in the trigger word sent to the L0TP for comparison with the appropriate masks.

• Extra information needed in the SL:– 1 bit (PV region) – 2 bits (quadrants) → not needed with 4xTDCBs

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An alternative PP


• An alternative setup could do the following:– Modify the hardware (soldering a connection) to form a hardware-level OR

between the two channels in each slab → roughly factor 2x reduction in input rate, but lose a lot of information about the type of hit (although theres no issue with Cherenkov light like in MUV3)

– Use the PPs to cluster hits, reducing the 45MHz input rate down to the 10MHz particle rate. This firmware could be produced in conjunction with other systems with too-high input rates

– Send the clusters to the SL for second-stage clustering. More information per hit needs to be transferred, but much less hits (since they are now clusters).

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Summary


• The MUV3 and NewCHOD systems are very similar• With two channels per slab, coincidences being made in the PP• They can be read out with 1xTEL62, 3-4xTDCBs

• CHOD has a 3x higher input rate, but a 25% lower output rate

• Evgueni’s proposed NewCHOD triggers can be implemented by extending techniques already being used in MUV 3

• An alternative using a clustering-PP design might be needed given the large fluctuations in the beam intensity observed last year

• Need an SVN location to store/develop the NewCHOD firmware

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NewCHOD Firmware Chris Parkinson, University of Birmingham 16 th December 2015 1