July 10, 2008 PHENIX RPC review C.Y. Chi 1 RPC Front End Electronics On chamber discriminator  The strips  The CMS discriminator chips  The discriminator board  Test results The TDC board  The TDC and Crate block diagram  The TDC board test result  The trigger board The board counts Status

July 10, 2008 PHENIX RPC review C.Y. Chi 2 RPC Strip Our chamber is closely follow the CMS design. Our on-chamber electronics will try to follow their electronics too. The CMS barrel strips is 1.3m long, 4 cm or 2cm wide.  15/40 ohms impedance. 420pf/160pf capacitance.  Fully terminated strips. CMS endcap RPC  Cover 5/16 degree in phi, 7 to 38mm in width and 22 to 55 cm in length  Un-terminated.  Lemo cables are used to connect strip to the discriminator board PHENIX RPC strip width range from 11.4 mm by 141mm to 64.6 mm by 554.2mm.  The smallest one has 46 ohms impedance and 16 pf of capacitance.  The largest one has 10 ohms impedance and 286 pf of capacitance.

July 10, 2008 PHENIX RPC review C.Y. Chi 3 CMS RPC preamp/discriminator chip Build on AMS 0.8 um BiCMOS process, +5V device. 15 ohms input impendence. 45mW/channel. 8 channels per chip. It is designed in Bari, Italy. It has preamp, gain stage, zero crossing discriminator, monostable (cover the dead time) and LVDS driver. The chip is designed to deal with 20 fC up to 20 pC with1.7fC ENC noise. Zero crossing is necessary to deal with large dynamic range. The time walk is about.6ns except for very large charge. Testing show that threshold level could be as high as 100fc without loosing efficiency. All the chips has been fabricated. Two wafers has been packaged and tested.

July 10, 2008 PHENIX RPC review C.Y. Chi 4 Cable adapter board RPC 32 channel discriminator board 32 channels per board Fused +6V input analog/digital power supply ~.46A (use +5V, +3V through low drop regulators) Serial download is used to set 10 bits 4 channel threshold DAC (4mv per bin) and Fire test pulse. LVDS discriminator output Serial download

July 10, 2008 PHENIX RPC review C.Y. Chi 5 RPC disc 32 ch 3M PL Or pl RPC TDC 64 ch Half octant Module edge Adapter Board Adapter Board 2-3 m cable ?8 meters cable ? 2-3 m cable?8 meter cable ? 3M (Gray) M (Black) RB 3M (Gray) M N3432-L302RB 3M (Black) D89140-???? Signal Cable : 40 conductors twist flat ribbon cable 3M (gray) M M 1700/40 Twisted Pair, Flat Cable,.050" 28 AWG Stranded Fire rating VW-1 16 short RG174 cables Connection diagram

July 10, 2008 PHENIX RPC review C.Y. Chi 6 The discriminator is moving 4mv per step. The test pulse is feed to the input amplify through 1pf cap. (not for calibration, functional check only) Channel 14 TDC distribution, DAC step =80 TDC step On board test pulse vs. threshold study

July 10, 2008 PHENIX RPC review C.Y. Chi 7 CMS Disc threshold Channel 26 Channel 28 Channel 32Channel 30 Channel 32 Threshold (8 mv per step) TDC TDC distribution at step =20 (160mv) Direct pulse injection (threshold effect) Test pulse is set around ~ 4mv input

July 10, 2008 PHENIX RPC review C.Y. Chi 8 Direct Pulse Injection (fixed threshold) Inject test pulse through the cable adapter card + 10pf capacitance (channel 45) 2mv per step, 160mv threshold (~80fc) Cross talk seen at round 100mv. Input (steps) Channel 45 TDC Channel 46Channel 44 disc. fired

July 10, 2008 PHENIX RPC review C.Y. Chi 9 DISC LVDS output at discriminator board DISC output after ~10 meter cables 69 ns time difference 1.61ns/ft  ~42 ft Digitally subtracted pulse between + and – side of discriminator LVDS output 500mv per division 1.4V 1.63V Long output cable study

July 10, 2008 PHENIX RPC review C.Y. Chi 10 DISCDISC LVDS Receiver Trigger window 32 channel digitizer PLL Test Pulse LVDS Transmitter 4x beam clock 44X BC Test Pulse MASK Serial download Disc Serial download TDC serial download Interface Chip Collects 64 Channel Of Data Digitized Data L1 trigger etc L1 trigger primitives L1 trigger primitives Serial Download Timing etc. Event Data Event Data RPC TDC MODULE

July 10, 2008 PHENIX RPC review C.Y. Chi 11 The TDC Internal Test Pulse Scan test pulse step average TDC valueSigma on the TDC TDC: Use 44X beam crossing clock to digitized the discriminated LVDS pulse, ~2.5ns for 9.6MHz RHIC clock Test Pulse: Generated internally with the FPGA with the same 44x beam crossing clock Trigger Window: The lower and upper limits be can set channel by channel Mask: Mask bits can be set to turn off individual channel. Serial data to Discriminator Board: Control test pulse firing and discriminator threshold ( chip by chip) TDC Module

July 10, 2008 PHENIX RPC review C.Y. Chi 12 RPC(HBD) crate/BUS structure 6Ux160 mm VME size TDCTDC TDCTDC Output To L1 Clock fanout L1 primitives L1 GTM Slow Control TDCs XMIT DCM Clock Master RPC FEM crate

July 10, 2008 PHENIX RPC review C.Y. Chi 13 Trigger data from FEM 1 pair of cable per FEM Arria FPGA De-serialized FEM data & format trigger data Transceiver blocks RPC Trigger Board Optical transmitter 2.8 Gbits/sec RPC triggers is being designed. Schedule for prototype around Sept. The module can receive up to 6FEM’s trigger data The optical trigger data contains, idle, clock numbers and up to 12 16bits FEM trigger data every beam crossing.

14 Channel count etc… (one side) Station1a+b23total Channel Channel per FEM (TDC) FEM (TDC) Disc Board L1 trigger Fibers FEM/ fibers646 Support board/crate 343 FEM/crate Crates44412 The crate size is like 6U VME crate. I would like to limit the length discriminator cable to 10 meters. (to be tested about jitters) The RPC2, 3, we will need to find the crate space near the detector. Crate need to be recess in the rack. Cable routing space needed in front of the crate.

15 Channel count etc with RPC2/3 strips combined… (one side) Station1a+b23total Channel3072~3848/2~2872/2 Channel per FEM (TDC) 64 FEM (TDC) Disc Board L1 trigger Fibers FEM/ fibers623 XMIT to DCM 454 L1 boards 884 FEM/crate 12~1012 Crates432 The crate size is like 6U VME crate. I would like to limit the length discriminator cable to 10 meters. (to be tested about jitters) The RPC2, 3, we will need to find the crate space near the detector. Crate need to be recess in the rack. Cable routing space needed in front of the crate.

July 10, 2008 PHENIX RPC review C.Y. Chi 16 STATUS The discriminator and TDC modules has been successfully prototyped. Waiting for on chamber testing.  Grounding issue need to be resolved with chamber testing CMS 32 channel board has been tested in both Colorado and BNL factory. We are building, 40 discriminator modules, 20 TDC boards, 3 sets of crates+ clock master modules for the coming run and individual factory readout/test stand. Trigger modules is being designed.