E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Front-end Readout of the CMS Hadronic Forward Calorimeter (HF) Conceptual Design (Summary) by Eric Hazen and Jim Rohlf Boston University

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Summary 9U modules (6 readout cards each) are cost-effective, manageable way to package the HF readout Total of 8 crates, each with 9 readout modules (72 modules needed) Controller module uses the standard TIMING, SERIAL and TEMP cards (8 needed) WBS contains only 54 modules but cost per unit is “reasonable”  need to add 26 modules + spares Schedule is strongly influenced by arrival of first readout and control cards

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Cost Comparison: RBX vs. VME

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Production Cost Comparison: WBS vs. Conceptual Design * Cost based on quotes for DCC modules *

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 For comparison:

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Development Schedule (WBS)

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Development Schedule (New) Note: Detailed design cannot start until FE card design is complete

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Readout Options 1) HB readout boxes Internal water cooling Severe cabling problems for HF Expensive (compare later) 2)HB readout cards in custom crates with FNAL backplane Must engineer entire crate! 3)HB readout cards in 3U crates Non-standard card spacing requires a custom backplane to make any sense Multiple crates per quadrant

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Readout Options, cont. 4) 9U standard VME* crate with readout cards as daughterboards This option is our preferred choice on the basis of both ease of implementation and cost * VME Bus not used except possibly for diagnostics

E. Hazen, Boston University BU Meeting, Apr. 6, Channels (includes “ECAL” & “TC”) 1224 Channels per end 306 Channels per quadrant (4 crates on each end) 51 Readout cards per crate (6 QIE per card) HF Channel Count 306  need 51 Readout cards per crate 306 = 9 x 34

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 One HF Module per PMT Box (to scale!) Backup Only

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 HF Readout Module External coax cabling from PMT input to readout card (36 total) Multisignal microcoax connector

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 HF Crate Layout (8 total) TTC in CAN bus RBX bus Fiber out

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Each Crate has: One controller 9 readout modules (324 channel capacity) “RBX bus” inter-card connection via front panel cables 306 input signal cables Connector panel on or near back of crate where larger coax is converted to micro- coax 18 front panel 9-fiber optical connectors for output

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Crate Location

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 HF Readout Module Block Diagram

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 HF Readout Module (summary): 36 input cables (possibly an Axon multi-microcoax connector) External coax cabling to each of 6 readout cards Internal “RBX bus” at center of card, so that digital operations occupy adjacent real estate “RBX bus” cable input on front panel Two 9-fiber optical connectors on the front panel for output to the HTR Power and system reset via 3U VME backplane (J1)

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 HF Controller Motherboard

E. Hazen, Boston University BU Meeting, Apr. 6, 2001 Controller Motherboard: Three controller daughter cards, Timing, Serial and Temperature One TTC front-panel fiber connector (input) Nine cat-5 front-panel connectors to distribute “RBX bus” to readout modules (4-pin + 5-pin or 10-pin) One 9-pin D-type front-panel CAN bus connector