1. ETD summary D. Breton, S.Luitz, U.Marconi
Summary session - Frascati Meeting
December 4th 2009

2. Number of readout links
We held the front-end dedicated session Wednesday:
Each sub-detector was able to present an estimation of its number of links
It was mostly targetting the readout links
The numbers are very reasonable for the triggered systems:
SVT : 58
DCH : 30 (35 for the trigger primitives)
Barrel PID : 12
Forward PID : DIRC-like TOF -> 1 to 12, FARICH -> ~30
IFR : 40
They are less reasonable for an untriggered calorimeter, after refining during the calorimeter and general ETD session:
Barrel : 960
Forward : 900 (could be less with more optimization but > 600)
we propose another solution:
each IOB sends one 1.25Gbits/s link to EMT and one 2Gbit/s link to ROM
this perfectly fits with a 3x4-crystal sum which looks fine for trigger granularity

3. Other links and safety factors
We commonly estimated that for all the systems, the numbers of ECS and FCTS links could be the same as that of the readout links
total of ~330 links both for ECS and FCTS.
It was agreed to have mezzanines for ECS and FCTS on the detector side
Still to be discussed for off-detector use
FCTS mezzanines have to be bi-directionnal to be used for sending the trigger information to the EMT and DCT.
We would like to get the safety factors used for the readout link calculations for each subsystem and to understand what they are based on.
Subsystems shouldn’t apply general safety margins like that on trigger rate
=> that one will be common to the whole experiment
But they should for what concerns their channel occupancy (based on channel hit rate and trigger window width)

4. ROMs and event size
These numbers allowed us to produce the first estimation of the ETD cost.
We had to make a guess about the number of ROMs.
We assumed that:
1 crate per sub-detector would be necessary
This would allow to ensure an easy partitionning of the system
8 links per ROM would be very conservative (16 Gbits/s input rate)
This number mainly depends on the smaller data compression ratio of all subsystems
This leads us to the following request, in junction with the event size estimation:
We would like all subdetector to estimate:
The event size at the input of the ROM
What type of event processing (zero suppression, data compression, digital filtering, feature extraction, …) you feel like performing inside the ROM
The event size after said processing
These numbers are necessary in order to scale the load on the network and the PC farm

5. Option 1: untriggered EMC

6. Option 2: triggered EMC

7. ETD elements for SuperB_costing
EDIA [mm] M&S [k€]
1.7.10
ETD (without Trigger)
FCTS
144
150
FCTS crates and supplies 2 30
Control and Distribution Module (2) 12 10
Fast Control and Timing Module (15) 84 60
Clock & Control Link Switch Module (7) 36 40
Throttle Switch Module (2)
CFEE
FCTS mezzanine (400 + protos) 48
140
Level 1 Buffer Control 6
Readout link control & serializer
Option 1: triggered EMC => 400
Option 2: untriggered EMC => 1700
500
ROM
ROM crates and supplies (5) 75
ROM crate controller (7) 50
ROM boards (40 ? 8 links/board)
200
ECS
SPECS masters (400 + protos) 3
100
SPECS Mezzanine (400 + protos) 80
SPECS links (330 cat5+ cables) 15
Clock & Control Links (330) 20
Readout links
Option 1: triggered EMC => 330 links
Option 2: untriggered EMC => 1600 links

8. About WBS … We now have the first estimation for ETD cost:
the overal cost is ~1M€
this covers all the ETD hardware, except the L1 trigger which was already quoted in the CDR
We have to check the numbers for the latter
As Francesco pointed it out again last night, electronics chapter actually includes everything you cannot remove from the detector, except with a hammer!
This includes almost all the front-end electronics (even power supplies and cables)
We (Steffen, Umberto and I) cannot check the numbers ourselves, just try to check that nothing was forgotten
So we officially request here the subdetectors to upgrade their electronics sections of the document
To this end, and commonly, we fixed the deadline to next Monday, 9AM …

9. Our proposal for trigger
We propose to have:
a triggered calorimeter electronics for the obvious reason of cost (this saves ~500k€ on links!)
the highest affordable granularity for the trigger cell sums
this means that on each IOB, we implement one 1.25Gb/s synchronous link for the trigger sums, this corresponding to 3x4 crystals
this link can be the unused return path of the link used for FCTS
=> this is almost for free!
On the EMT side, we would like to have a single crate, which would be the most effective for the neighbouring studies
We could build trigger cells made of 4 neighbouring sums, which would overlap inside the trigger processing, producing an effective 2D map (BABAR was 1D).
We need to understand if an effective bhabha veto could be built on the basis of such an architecture.
We need to understand and simulate the performance of this architecture for all SuperB physics cases.

10. Proposed calorimeter implementation
12 regions along θ
3x4 crystals region
3x4 crystals region
40 ϕ sectors
Energy is summed over the
3x4 crystals region
6 energy sums will be continuously transmitted through a single optical serial 1.25 Gb/s
The 3x4 regions can be overlapped in the EMT
IOB
1.25 Gb/s
synchronous link
To EMT

11. Conclusion We now have the first estimation for:
Number of FCTS, ECS and readout links
Number of ROMs (~40)
This allowed us to estimate the ETD cost, non including the trigger: ~1M€
We request the subdetector teams to update their sections of the WBS document
We proposed a new architecture for the EMT trigger
=> To be farther studied and simulated
We should be able to have a first draft of our white paper section before Christmas.