Transcript CLAS12 Drift Chamber Electronics

Drift Chamber Review
Jefferson Lab
6-8 March 2007
CLAS12 Drift Chamber Electronics
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
R. Chris Cuevas
Group Leader -- Fast Electronics
Jefferson Lab
Physics Division
30 cm
CLAS12 WC
165 cm
CLAS12
Region 1
Wire Chamber
1 Sector
190 cm
CLAS12 Cutaway View
AutoCad Design by
Steve Christo
CLAS Review
CLAS Drift Chamber Electronics
A Brief Review
• 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 Review
CLAS Region 3
Drift Chamber
Note: High Voltage Boards
CLAS Drift Chamber Electronics
A Brief Review
CLAS Region 2
Signal ‘Translator’ Board
CLAS12 Drift Chamber Electronics
CLAS12 Interface
Circuit Board
Conductive
Rubber
Plastic Insert
Plated Hole
Copper trace
Wire
Feedthrough
Crimp
Pin
3kv
High Voltage Clearance
Use 0.25mm/100Vdc
Endplate
P
R
E
A
M
P
Signal ‘Translator’ Board
So, 1850Vdc on Sense Wire
demands 4.625mm (0.182”)
clearance.
Reference: IPC-2221A
Circuit Board Conductor Spacing
CLAS12 Interface
CLAS12 Drift Chamber Electronics
Pre-Amplifier
Technology
Dimensions
Gain
Rise Time
Input Noise
Dynamic Range
Power Supply
Thick-film on Al2O3 substrate
8-pin, Single-In-line (SIP)
0.80” L X 0.45” H X 0.08” W
2.3 mV/A
4.3 nS
< 250 nA
200 A
+5V DC, 13 mA
Original Version: NOT coated (1994)
Epoxy Coated Version: 2003
CLAS Note 92-003
The CLAS Pre-Amplifier
Fernando Barbosa
CLAS12 Drift Chamber Electronics
CLAS12 Interface
Wire Chamber Signals
Amplifier Discriminator Board
X
X
Pre-amp
75 ft
X
ADB from CLAS
will be used for
CLAS12
S
X
MIP
X
X
Threshold
+HV
• 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.
CLAS12 Interface
CLAS12 Drift Chamber Electronics
CLAS12 Interface
CLAS12 Drift Chamber Electronics
‘Post Amplifier’ circuit section
From Amplifier-Discriminator Board
From Pre-Amp
+75 Ft twisted pair cable
(100 Ohm termination not shown)
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
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.
Pre-Amplifier Power Dissipation
Pre-Amplifer Power Dissipation
16 Preamps powered by one
regulator
Pre-Amp Current
Pre-Amp Voltage
Power
#Pre-Amps
0.013 A
5
0.065
96
Regulator Power
Drop Out Voltage
16 PreAmps
#Regulators
1.5
0.208 A
6
Total/STB
7 STB/Superlayer
Total(W)
6.24
1.872
8.112
7
Watts per Superlayer
56.784
Total for 1 Region in 1 Sector
113.568
CLAS12 Super-layers
Region 3
(6) (6)
Region 2
(6) (6)
Region 1
(6) (6)
U
V
Wire Chamber Diagram -- 1 Sector
Two (2) Super-layers per Region
Six (6) Sense Wire Layers per Super-layer
U
V
U
V
BEAM
CLAS12 STB
CLAS12 Signal Translator Boards ( 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
CLAS12 Signal Translator Boards ( STB)
CLAS12 STB
233mm
Low Voltage Input
Local Voltage Regulator
16 channel Pre-Amplifier ‘groups’
17th pair used as test pulse input
6 ‘groups’ of 16 == 96 channels
220mm
PCB
Connector
Side View Sketch
SIPS
End Plate Support
CLAS12 HV
CLAS12 High Voltage Distribution Boards
•
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
Cabling & Connections
High Voltage Boards
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 Signal Translator Boards ( STB )
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
CLAS12 WC Cabling
Cabling & Connections Signal Translator Boards ( STB )
6
96 Channels
C
A
B
L
E
STB7V
6
96 Channels
STB6V
I
N
T
E
R
F
A
C
E
6
96 Channels
STB5V
6
96 Channels
STB4V
6
96 Channels
STB3V
6
96 Channels
STB2V
Use existing cables
To Readout Electronics
17 Pair
‘0.025” Pitch’
Smaller O.D.
Use existing LV Supplies
And Fuse Protection
hardware
17 Pair
‘Standard Pitch’
STB1V
-
FUSE Chassis
6
96 Channels
+
7
LOW VOLTAGE
DISTRIBUTION
7
CLAS12 WC Cabling
CLAS12 Drift Chamber Electronics
Low Profile Box Header
PCB Connector
$3.10 for qty >1000
17 pair; 0.025” pitch; 0.3” Nominal O.D.
$4 per foot from preliminary budget estimate; Need ~15K feet
CLAS12 Drift Chambers
Channel & Board Count
CLAS12
#Sense
Wires
Sense
#Layers Wires
96
Channel
per
Sector
STB
LV
Cables
STB
Output
Cables
96
Channel
HV
Board
STB
HV
Cables
HV Board
R1_U
112
6
672
7
7
42
7
7
R1_V
112
6
672
7
7
42
7
7
R2_U
112
6
672
7
7
42
7
7
R2_V
112
6
672
7
7
42
7
7
R3_U
112
6
672
7
7
42
7
7
R3_V
112
6
672
7
7
42
7
7
4032
42
42
252
42
42
6
6
6
6
6
6
24192
252
252
1512
252
252
6 Sector
Multiplier
Totals
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
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.