IPAS SPring-8 FADC Project
章文箴
蘇大順
04/26/2002
Super Photon Ring 8 GeV (SPring-8)
Harima Science Garden City
Laser Electron Photon
LEPS Detector Configuration
TPC inside LEPS Detectors
Time Projection Chamber
Working Principles of
Time Projection Chamber
1.
2.
3.
4.
Passage of charged particles through the gas generates
ionization electrons.
Electrons drift towards the readout plane along the
imposed E x B drifting fields.
At the end of readout plane, an avalanche
(amplification) will happen upon the arrival of
electrons by the proportional sense wires and an
induced image charge on the corresponding cathode
pads.
The pads are connected with a read-out electronics
which provides low-noise and high resolution
analogue information as well as the drift time
associated with the signal.
Electric Field Configuration
Grid Wire
Sense Wire
Field Wires
Cathod
Determination of
the Particle Trajectory
Particle Identification by
dE/dx vs. P
Time Projection Chamber at
SPring-8 LEPS Experiment
Time Projection Chamber at
Spring-8 LEPS Experiment
Readout Pads of TPC
Zoom-in View of Wires
TPC Inside the Solenoid Magnet
at SPring-8
View of Particle Trajectory
along the beam in Simulation
TPC Mechanical Specification
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•
•
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Inner radius: < 1.25 cm.
Outer radius: < 30 cm.
Read out channels: 95 sensing wires, 1000 pads.
Pad size:inner 8mm*8mm, outer 8mm*13mm.
Distance between sensing wires and pads: 4mm.
Separation of sensing wire: 4mm.
Cathode readout.
Maximum drift distance : about 70 cm.
Maximum drift time: about 14 sec with drift velocity
= 5.1 cm/sec.
Requirement of TPC Electronics
• Good energy resolution: measuring dE/dx from the charge
readout of either wires or pads for the particle identification for
K/p separation at low momentum.
• Requirement of spatial resolution:
– x,y < 300 m.
– z < 1 mm.
• Position information:
– x(t),y(t): x from fired sense wires; y from interpolation of
signals on pads(t).
– z(t) from time bin of FADC time slice.
• Timing information: fitting of pulse peak in FADC.
• On-board zero-suppression to ensure fast data transfer and short
system dead time.
Digitizer in TPC Electronic: FADC
• Large data size:
– High sampling rate: 40 MHz = 25 nsec.
– Read-out bit (Nbit): 10 bits.
– # of Time bins per event: ~600 time bins. (Max drift time/clock =
14 sec/25 nsec = 560 bins.)
– 1000 channels.
• Trigger latency: 1 sec .
• On-board zero-suppression.
• Need of a large buffer size to store 4-5 events on board for
one single VME readout.(16*600*5=48K per channel, w/o
a zero suppression factor.)
• High channel density.
SPring-8 FADC Module
– Use TEXONO FADC and IHEP BES version as the
starting point.
– 40 MHz; 10-bit FADC: input 0-2 V range.
– Shift register inside FPGA: length = trigger latency (1
s).
– On-board FPGA for threshold suppression.
– Buffer FIFO: dual port memory.
– CPLD: controlling VME actions.
– Free clock running.
– VME 9U; 32 channels/module; 8 attached
cards/module; 4 channel/card.
Main Electronic Components
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Receiver: MAXIM, MAX4145ESD.
OPA: Analog Device, AD8138ARSO-8.
FADC: Analog Device, AD9203ARVRU-28.
FPGA: Xilinx, XC2S150-6FG456.
FIFO: TI, SN74V245.
SPring-8 FADC Module
(4 channels, 10 bits, 40 MHz)
FIFO
FADC
OPA
FPGA
Mixed signal AD Converter Adapter Board
40 MHz sampling rate.
10 bits resolution with 2Vp-p dynamic range.
Clock distribution with Phase Lock Loop circuit.
On Board digital signal delay and
Real-Time ZERO-Suppression.
High capacity First In First Out Memory.
Easy to use with high density connector.
FADC Mother Board
Driver
CPLD
Clock Driver
VME Connector
VMEBus slave controller,
with high performance BLTransfer Mode.
FPGA,
digital signal control chip.
First In First Out memory.
Differential AD Converter (40 MHz)
16 channels differential signal input
connector.
32 Channels, high sampling rate
Flash AD converter.
Spring-8 2002/03
Differential Signal
from MAMP
CH 2
CH 3
CH 4
Receiver
& Driver
FADC
Receiver
& Driver
FADC
x8
Four Channels
Download
PROM
10
10
Receiver
& Driver
FADC
Receiver
& Driver
FADC
VA[8..15]
Processing
FPGA
VD[0..31]
Download
PROM
Write Flag
Read
RST
Flag
CH 1
10
10
4
Clock
Trigger
Hit Flag
FIFO
x8
VD[0..31]
VD1
JTAG
VD[0..11]
Reset
Trigger
Counter
12
Delay
VD[0..11]
Trigger
FIFO
Read Flag
Write_in
Read_out
Write
Read Trigger FIFO
Clear Trigger FIFO
Check Trigger Number
VME_Reset
VME
Control
VA[8..23]
VA1
AS,D0,D1,AM[0..5],Write,DTACK, et. al.
VC
8
Global FPGA
8 bits DIP Switch
10
L=(Trigger Latency + 1)
10 bits Data
10
Shift Register
32 bits FIFO
10
Comparator
Flag
Q
S
10
Threshold
R
VD[0…15]
VD2
VA[8…15]
VA2
Write Flag
Read
Clock Counter & Control
Trigger
Clock
Rst
Count
Over_Threshold
Enable
Comp_Control
Clock
Write_header&trailer
Write_Data
Reset
Write_Flag
Disable
Clear
Fig. 2 Block Diagram of Processing FPGA
CS: Checksum bit
ND: Not defined.
16
15
Data Format
11
10
09
08
07
06
Lowest Bit
14
13
12
05
04
03
0
1
ND
0
0
1
ND
0
1
0
ND
ND
ADC (0-1024)
0
1
1
ND
ND
Time (0-1024)
0
0
ND
ND
Number of ADC data bins (0-600)
02
01
Header 1
CS
0
Header 2
CS
FADC Module Number (1-64)
Channel Number (1-32)
Event Number (1-5)
ADC
CS
Time
CS
Trailer
CS
1
CSR Format
Lowest Bit
VME address: 0x010000
16
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
Reset
1
Sampling Count: default value 1020.
1
0
0
Last six digits of number of
sampling count.
FADC VME Action List (A24/D16)
• 0x0i0000: address to write, bit 9 for resetting FIFO and set
ready, bit 10 for resetting suppression threshold and bit 11 for
setting the sample count of the FADC i. (Address modifier:
0x3D).
• 0x0i0100: address to read the merged 32 FIFOs’ content in BLT
mode for FADC i. (Address modifier: 0x3B, 0x3F).
• 0x0i0101: address to read the BLT reading cycle for FADC i.
(Address modifier: 0x3B, 0x3F).
• 0x0i0000+j*0x000100: address to read the single FIFO content
in AO mode for channel j. (Address modifier: 0x3D)
• 0x0i0000+j*0x000100: address to write for setting the zerosuppression threshold for channel j. (Address modifier: 0x3D)
The Control Flow of FADC
For each channel
DAQ Start
Trigger , Conversion
NIM
Preamplifier Module
Trigger Count *Veto
Master
VME
< 5 events
CPU
Send IRQ to VME CPU
Yes
No
Trigger signal
CPLD FADC Trigger Clock
DAQ READ FIFO
100MHz
DAQ send Reset
FADC Module
Trigger
FADC
FADC clear BUSY
Reset
Busy
Slave
Clear trigger Veto
Observation Window of Signals
Signal
Shift Register Length ( max 100*25ns = 2.5 s)
Trigger
Conversion Strobe
Sampling Counts ( max 1024*25ns=25s)
DAQ Trigger Logic
LeCroy222
TEXONO
MAMP
Full scale width
1.0 10
100
100
1.0
10
10
1.0 LATCH
L VT
H VT
LTDS1
Voltage Reference
START BUSY STOP
Rst
OR
NIM
NIM
BLANK TTL
DEL
LTD0
Strb
Full scale width
1.0 10
100
100
1.0
10
10
1.0 LATCH
SCLK
HTD0
Evnt
Clock Generator
START BUSY STOP
NIM
NIM
BLANK TTL
DEL
Reset
Busy
Trigger
CLK
READ
INT
FBSY
OR
+5V -5.2V +12V -12V
SPring-8 32-channel FADC
TEXONO Online Event Display
(400 KHz sine wave)
TEXONO Online Event Display
(1 MHz sine wave)
ROOT Offline Event Display for
2 SPring-8 FADC (64 channels)
Module 1
Module 2
Events
• 02/09/2001: Prof. Imai and Ahn visited AS. Collaborating
plan was discussed and finalized.
• 03/31/2001: Wen-Chen and Henry visited IHEP, Beijing
and explored the R&D plan in IHEP.
• 05/31/2001: IHEP was not able to perform the R&D plan.
• 08/01/2001: Da-Shun visited IHEP for 3 weeks to learn the
conceptual design.
• 02/01/2002: Prototype 1 boards made.
• 02/28/2002: Wen-Chen and Da-Shun tested prototype-1
boards with TPC at SPring-8.
• 04/25/2002: Finished up 64 channels of prototype-1 and
deliver them to SPring-8.
Plan
• 04/30/2002: Issue out prototype-2 (quasi-final) fabrication
order.
• 05/21/2002: Deliver prototype-2 to SPring-8.
• 06/01/2002: System test with a complete electronic chain
(Pre-amp, shaper, and FADC) with TPC and Solenoid
magnet.
• 06/15/2002: Issue out final production fabrication order
(1440 channels).
• 07/01/2002: Send production boards for stuffing.
• 07/15/2002 – 07/31/2002: Test production boards.
• 08/01/2002 – 08/31/2002: Delivery of production board,
installation, system test and DAQ.
• 09/15/2002: Commission Run with photon beam.
Remarks
• Many valuable experiences learned: board
design, firmware, modification of TEXONO
DAQ, coordinating people, etc.
• A good starting point for a continuing
“rooting” process of experimental technique
at IPAS.
• Thanks to many people: Henry, P.K., A.C.,
K.C., Tracy, IHEP group….