1. Drift Chamber Review Jefferson Lab 6-8 March 2007 CLAS12 Drift Chamber Electronics R. Chris Cuevas Group Leader -- Fast Electronics Jefferson Lab Physics Division Topics: Wire Chamber Model Diagrams CLAS – A Brief Review Interface – Pre-Amplifier Wire Chamber Electrical ‘Circuit’ Signal ‘Translator’ Board (STB) Power Dissipation High Voltage Distribution Cabling and Connections Channel & Board Count Summary

2. CLAS12 WC 190 cm 30 cm 165 cm CLAS12 Cutaway View AutoCad Design by Steve Christo CLAS12 Region 1 Wire Chamber 1 Sector

3. CLAS drift chamber reliability and experience is >10 years. Method to interface wires to circuit board has been very successful. Conductive Rubber ‘boot’ around crimp pins No radiation damage to rubber Reusable, low stress on crimp pin Good contact to circuit board hole Pre-amplifier is mounted directly to an interface board and connected to Sense wire by circuit trace. Local voltage regulation for Pre-amplifiers on interface board Uncoated Pre-Amplifiers were showing signs of ‘whisker’ growth Low component count per interface board CLAS Drift Chamber Electronics A Brief Review CLAS Review

4. CLAS Drift Chamber Electronics A Brief Review CLAS Review CLAS Region 3 Drift Chamber Note: High Voltage Boards CLAS Region 2 Signal ‘Translator’ Board

5. CLAS12 Interface Wire Feedthrough Endplate Crimp Pin Conductive Rubber Circuit Board Plated Hole Copper trace Signal ‘Translator’ Board Plastic Insert CLAS12 Drift Chamber Electronics High Voltage Clearance Use 0.25mm/100Vdc So, 1850Vdc on Sense Wire demands 4.625mm (0.182”) clearance. PREAMPPREAMP 3kv Reference: IPC-2221A Circuit Board Conductor Spacing

6. CLAS12 Drift Chamber Electronics Pre-Amplifier CLAS12 Interface TechnologyThick-film on Al 2 O 3 substrate Dimensions8-pin, Single-In-line (SIP) 0.80” L X 0.45” H X 0.08” W Gain2.3 mV/  A Rise Time4.3 nS Input Noise< 250 nA Dynamic Range200  A Power Supply+5V DC, 13 mA CLAS Note 92-003 The CLAS Pre-Amplifier Fernando Barbosa Original Version: NOT coated (1994) Epoxy Coated Version: 2003

7. CLAS12 Drift Chamber Electronics CLAS12 Interface Wire Chamber Signals X X X X X X S Gas gain == 5 x 10 4 Use 4 electrons from Ionizing Particle – “Corner Clip” signal Use 10nS peak current time 3.2uA Sense wire signal to Pre-Amplifier from MIP Preamplifier is a trans-impedance amplifier with a 2mV/uA gain. ‘Post Amplifier’ receives differential signal and compensates cable attenuation and adds additional gain stage. Pre-Amplifier combined with Post Amp/Receiver allow discriminator setting to be above the chamber input noise( <0.4ua ) and still be sensitive to MIP signals for good timing resolution. MIP +HV Threshold Pre-amp Amplifier Discriminator Board 75 ft ADB from CLAS will be used for CLAS12

8. CLAS12 Drift Chamber Electronics CLAS12 Interface

9. CLAS12 Drift Chamber Electronics CLAS12 Interface ‘Post Amplifier’ circuit section From Amplifier-Discriminator Board Note: Two gains possible Small signals Av=30 Large signals Av=10 Discriminator stage not shown, but typical discriminator setting is 30mV The ADB, and Multiplexer boards will be used for the CLAS12 From Pre-Amp +75 Ft twisted pair cable (100 Ohm termination not shown)

10. CLAS12 Electrical Circuit Notes: 1. Electrical Diagram for a single Wire Chamber “Cell” Notes: 1.32 Field Wire Pins ‘Wrapped’ together on end plates 2.6 Sense Wire layers per superlayer 3.Each Sense Wire connected to HV through 1Meg resistor Pre-amp power is regulated and isolated from ground.

11. Pre-Amplifier Power Dissipation Pre-Amplifer Power Dissipation 16 Preamps powered by one regulator Pre-Amp CurrentPre-Amp VoltagePower#Pre-AmpsTotal(W) 0.013 A50.065966.24 Regulator PowerDrop Out Voltage16 PreAmps#Regulators 1.50.208 A61.872 Total/STB 8.112 7 STB/Superlayer 7 Watts per Superlayer 56.784 Total for 1 Region in 1 Sector 113.568

12. CLAS12 Super-layers Region 1 Region 2 UVUUVV BEAM (6) Region 3 Wire Chamber Diagram -- 1 Sector Two (2) Super-layers per Region Six (6) Sense Wire Layers per Super-layer (6)

13. CLAS12 Signal Translator Boards ( STB) CLAS12 STB Multi-Layer circuit board Glass Epoxy FR-4 for CLAS Investigating better material for CLAS12 boards (HVPF) Non hydroscopic, superior dielectric strength 7 identical boards per Super-Layer Wire Voltages: Region 1(s, f, g) = 1400, -700, 500 Region 2(s, f, g) = 1550, -775, 550 Region 3(s, f, g) = 1650, -825, 590 *Voltage supplied from HV boards *Must design STB board traces with adequate clearance for HV holes

14. CLAS12 STB CLAS12 Signal Translator Boards ( STB) 220mm 233mm End Plate Support Low Voltage Input Local Voltage Regulator 16 channel Pre-Amplifier ‘groups’ 17 th pair used as test pulse input 6 ‘groups’ of 16 == 96 channels Side View Sketch Connector SIPS PCB

15. Simple double layer circuit board Glass Epoxy FR-4 for CLAS Investigating better material for CLAS12 boards (HVPF) Non hydroscopic, superior dielectric strength 7 identical boards per Super-Layer HV supply cables soldered to the board CLAS12 High Voltage Distribution Boards CLAS12 HV

16. CLAS12 WC Cabling Multi-conductor cable sources HV to each board for each Super-Layer Seven(7) cables per Super-Layer High Voltage conductors for Sense, Field and Guard Wires 1 end of HV Cable are solder terminated on the boards 1 end of HV Cable connects to ‘Distribution Box” Cabling & Connections High Voltage Boards

17. CLAS12 WC Cabling Multi-conductor cable sources Low Voltage (LV) to STB for each Super-Layer Seven(7) LV cables per Super-Layer Low Voltage Segmentation: 32 Pre-Amplifiers per LV supply + V and return LV Cable is terminated with polarized latching connector on the STB LV Cable is terminated with polarized latching connector on ‘Distribution Box” Pre-Amplifier Output Cables Six(6) cables per STB per each Super-Layer – 84 Output Cables Total Smaller pitch twisted (0.025”) pair cable under consideration -- Saves space Normal pitch (0.050”) twisted pair will be used from ‘Interface Box’ To Readout Modules Cabling & Connections Signal Translator Boards ( STB ) 96Ch STB 7 LV Cables/Super-Layer 25 mil pitch twisted pair cable 42 cables/ Super-Layer

18. CLAS12 WC Cabling Cabling & Connections Signal Translator Boards ( STB ) STB1V STB2V STB3V STB4V STB5V STB6V STB7V 6 6 6 6 6 6 6 7 96 Channels CABLEINTERFACECABLEINTERFACE LOW VOLTAGE DISTRIBUTION Use existing LV Supplies And Fuse Protection hardware Use existing cables To Readout Electronics 17 Pair ‘Standard Pitch’ 17 Pair ‘0.025” Pitch’ Smaller O.D. + - FUSE Chassis 7

19. CLAS12 Drift Chamber Electronics CLAS12 WC Cabling 17 pair; 0.025” pitch; 0.3” Nominal O.D. $4 per foot from preliminary budget estimate; Need ~15K feet Low Profile Box Header PCB Connector $3.10 for qty >1000

20. CLAS12 Drift Chambers Channel & Board Count CLAS12 #Sense Wires #Layers Sense Wires 96 Channel LV Cables Output Cables 96 Channel HV Cables per SectorSTB HV Board R1_U1126672774277 R1_V1126672774277 R2_U1126672774277 R2_V1126672774277 R3_U1126672774277 R3_V1126672774277 403242 25242 6 Sector Multiplier 666666 Totals 24192252 1512252

21. Safety Notes Reference JLAB ESH&Q manual: Chapter 6230 Electronic Equipment Safety Class 1 Hazard – ( Low ) Low Voltage System < 50V < 50A High Voltage System >50V < 5mA All work performed in: Mode 1  De-energized Or Mode 2  Non-manipulative measurements Low Voltage power cables are fused and supply is programmed for over-current trip High Voltage supply is current limited ( 40uA ) per supply cable Soldering is performed with safety glasses Cutting component leads is performed with safety glasses Required Personal Protective Equipment [PPE] When using circuit board cleaning solvents Material Safety Data Sheets – Included with board cleaning procedure

22. Summary CLAS experience will be very valuable Wire interface to High Voltage boards and Pre-Amplifier boards is a proven method using conductive rubber connection Epoxy encapsulated Pre-Amps will eliminate corrosion problem Investigating the use of new circuit board materials for prototype testing. ‘Service’ connection area is planned for outer support plate of Wire Chamber section. Cable distribution for LV and Readout will use this area for interface hardware. New “Custom” Drift Chamber interface boards are based on successful designs.