Transcript Document 7515707

Electronics and Trigger developments for the
Diffractive Physics Proposal at 220m from
LHC-ATLAS
By P. Le Dû
[email protected]
J.F. Genat1, O. Kepka2 , P. Le Dû, Ch. Royon
For the RP220 collaboration
1
CNRS/IN2P3
2 DAPNIA.SPP and Institute
1-Nov-07
of Physics, Prague, Czech Republic
Hwaii 2007 -N43-4
1
Goals of this presentation
Present the feasibility study, R&D and issues
for the development of detectors to measure
protons at 220 m from the IP, within low 
optics at the LHC
Work associated or/and in collaboration with
– FP420 for the position detector (3D)
See N18-4 and N20-4
– UChicago/ANL/FNAL/Saclay/Photonis(Burle) for
the ultra fast timing detector (MCP)
N06-6 and N18-1
1-Nov-07
Hwaii 2007 -N43-4
2
Diffractive physics
Main physics aim pp  p+ X + p
Exclusive Higgs Signal over background: ∼ 1 if Mass resolution <
1Gev
New physics :SUSY search, Diffractive top, stop pair production
QCD studies
Photon induced interactions
Objective : reconstruct the M with a precision better than 1 Gev
Kinematics variable is
 = fractional momentum losses of the outgoing protons
b-jet
p
H
M 2= =  1  2 S
1-Nov-07
p
h
b-jet
Hwaii 2007 -N43-4
3
RP220 vs. other projects
Luminosity Monitors
(Low Luminosity)
QuickTime™ et un
décompresseur TIFF (LZW)
sont requis pour visionner cette image.
ATLAS
RP220
FP420
High Luminosity 1033 to 1034
Additional signal and flag at the L1 ATLAS Trigger
Natural follow-up of the ATLAS luminosity project at 240 m to
measure total cross section
Complementary to the FP420
1-Nov-07
Hwaii 2007 -N43-4
4
Trigger topologies
RP220 only
PLtrack
PL. AND PR track with ζ cut
Et JET 1 AND 2 > 40 Gev
JET Rapidity correlation ?
Dijet ENERGY /TOTAL > 0,9
JET 1
RP 220
RP 220
1 KHz @ 1033
20-30 KHz @ 1034
RP220 + FP420
PL Track
JET 2
PR track
PL track with ζ cut
Et JET 1 AND 2 > 40 Gev
JET 1 Rapidity Cut
Dijet ENERGY /TOTAL > 0,9
JET 1
RP 220
1,6 KHz @ 1033
1-Nov-07
JET 2
Hwaii 2007 -N43-4
FP420
5
Basics Requirements and Challenges
Measure  of each outgoing proton
– Position and direction with a precision of 10 
– Time of Flight (TOF) of the 2 outgoing protons with a
resolution of < 5 picoseconds
General system issues
– Mechanics and overall stability
integration with precision beam position monitor to reach 0(10) m
– Radiation for detectors at 220 meters (cryostat region)
– Detectors to operate very close to the beam (10  --> 1 mm)
– Trigger/selection issues
1-Nov-07
Hwaii 2007 -N43-4
6
Accumulated dose estimation @ 220 m (XRP3)
N. Mokhov, LHC Report 633
1-Nov-07
Hwaii 2007 -N43-4
7
Position Detectors
Position detectors
– Need to approach beam to the mm level
and stabilty of 10 m
– Should Achieve 10 m position
resolution
– Use EDGELESS Silicon detectors
TOTEM
Roman pot technique
For compact detectors
1-Nov-07
Hwaii 2007 -N43-4
8
Timing detectors
Measure the Time Of Flight of each diffracted
proton
Precision of few Picoseconds
– 1 mm on the vertex (select the right event among 35)
Technology --> Micro Channel Plate (MCP)
moving beampipe (HERA)
1-Nov-07
Hwaii 2007 -N43-4
9
Roman Pots location
RP
RP
220m
RP
RP
RP
RP
220m
IP
RP
{
Roman Pot Unit
1-Nov-07
Each RP station consists of two Roman
Pot Units separated by 8 m, centered
at 220m from IP1
Hwaii 2007 -N43-4
{
RP
Roman Pot Station
10
Roman Pots Layout
8m
Beam
Optics
IP
220m
3cm
Silicon
Detectors
One Horizontal pot
1-Nov-07
Hwaii 2007 -N43-4
Two Vertical pots
Elastic events for
calibration
and alignment
11
Layout
MCP-PMT
8x8
Pixels
X
U Y
V X
Radiator
3D pixels
Light
Guide
Size : 2,5 x 2,5 cm2
MCP
Timing detector
Movable Beam Pipe
1-Nov-07
MCP
S
D
I U O
D P W
E
N
Roman Pot B
Roman Pot A
2 x 21 planes of Si detectors
Hwaii 2007 -N43-4
12
Position detectors specific requirements
Objective : Achieve 10 m position resolution
–Two staggered 50 m pitch strips read in digital :
– 25 / 12 = 7.2 m resolution
– Or larger pitch analog using centroids
–Trigger data available within a few 100 ns
Candidates:
– Baseline: “3D” Pixels detectors (S. Parker)
–- NEW : Under development for RP420
3D
Stanford, VTT, Sintef
- Backup: Edgeless Silicon strips Experienced technology
Canberra, Hamamatsu
1-Nov-07
50m strips
(Canberra)
(Stanford)
Semi-3D detector
(VTT, Finland)
Hwaii 2007 -N43-4
13
3D Detector
Benefits compared to standard Si strips detectors)
Collection time
x 10
Low voltage depletion
/10
Radiation hardness
x50
Edgeless using plasma etching /10
Same charge as planar
Drawbacks
-
1-Nov-07
2 ns
10V
1015 p/cm2
5m
25 ke-/300 
Thickness:
Needs a bump-bonded chip
(could be thinned to 50m)
-
Production yield
Presently 80%
(7.2 x 8 mm2 detectors)
-
Readout speed
Slow as is: 2-6 s,
-
No ‘fast’ trigger data
Hwaii 2007 -N43-4
14
FE13 Readout chip
(ATLAS b-layer upgrade)
2880 channels
50 x 400 m2 pixels
7.2 x 8 mm2
Binary & Time Over Threshold
Self triggering
Time over Threshold
Adjustable threshold
CMOS 250nm IBM
Readout 2-6 s @ 40 MHz
8mm
7.2mm
Readout chip
IZM + Bonn
1-Nov-07
Hwaii 2007 -N43-4
Baseline for FP420
Need to be modified
for extracting the
Fast Trigger information
15
Fast (asynchronous) pixels digital readout
Trigger data
10-bit words
512
pixels
-
Fast ORs of columns (sufficient for the RP220 trigger)
Fast readout of every hit column
Fast address building takes a few ns in total (130nm CMOS)
Can be sent to the fast logic in the “alcove” at every BCO
X1
Y1---Y1n
X2
Y21---Y2m
--Xp
Yp---Ypq
Data transfer: 10 hits (disable noisy pixels) = 20 (10) words = 200 (100) bits
20ns (10) @ 10 Gb/s
1-Nov-07
Hwaii 2007 -N43-4
Jean-François Genat, RP220 meeting, Oct 17-19th 2007 Krakow, Poland
16
Alternative Read Out solution
Pixels connected as strips
Standard ABCD strips readout
Capacitance is higher, but does not impact small detectors
QuickTime™ et un
décompresseur TIFF (LZW)
sont requis pour visionner cette image.
Need to extract the Fast OR signal for trigger
1-Nov-07
Hwaii 2007 -N43-4
17
Micro Channel Plate PMT Operation
photon
Faceplate
Photocathode
Photoelectron
Dual MCP
DV ~ 200V
DV ~ 2000V
MCP-OUT
Pulse
Gain ~ 106
DV ~ 200V
Anode
A 2” x 2” MCP
actual thickness ~3/4”
Burle- Photonis MCP
2” x 2” sensitive area
1-Nov-07
Hwaii 2007 -N43-4
18
Major advance for generating the signal
Incoming
rel. particle
Use Cherenkov light fast
Custom Anode with
EqualTime Transmission
Lines + Capacitative. Return
Collect charge here
differential Input to
200 GHz TDC chip
Development of MCP’s
with 6-10 micron pore
diameters
1-Nov-07
10 m pores
Hwaii 2007 -N43-4
e.g. Burle
(Photonis)
85022with
19
mods
Simulation
RF Transmission Lines
Summing smaller anode
pads into 1by 1 readout
pixels
An equal time sum make
transmission lines equal
propagation times
Work on leading edge
ringing not a problem for
this fine segmentation
QuickTime™ et un
décompresseur TIFF (LZW)
sont requis pour visionner cette image.
Ability to simulate electronics
and systems to predict design
performance
Oscillator with predicted jitters
<< 100 femtosec
860 fs
20 Pe
1-Nov-07
Hwaii 2007 -N43-4
20
Read Out :Direction to reach 1(few) psec (1)
Picking the time
Temps / s
0,00E+00
– Multithreshold discriminator
5,00E-08
1,00E-07
1,50E-07
2,00E-07
2,50E-07
3,00E-07
3,50E-07
4,00E-07
1,00E-02
0,00E+00
-1,00E-02
Tension / V (50 Ohms)
-2,00E-02
M
C
P
-3,00E-02
-4,00E-02
-5,00E-02
-6,00E-02
-7,00E-02
-8,00E-02
1
2
3
4
Sigma (picoseconds)
Multi-threshold time resolution with actual
MCP pulses (2d order fit)
Extrapolated time
400
350
300
250
200
150
100
50
0
1
3
5
7
9
11
13
15
Number of thresholds
1-Nov-07
Hwaii 2007 -N43-4
21
QuickTime™ et un
décompresseur TIFF (LZW)
sont requis pour visionner cette image.
Direction to reach 1 psec (2)
Time Stretcher Scheme
“Slow” TDC
kd
IBM 8 HP Chip
M
C
P
DAQ
QuickTime™ et un
décompresseur TIFF (LZW)
sont requis pour visionner cette image.
Chip
Fukung Tang et al (UC-ANL).
200 MHz
TDC
(FPGA)
d
Resolution:
a few ps
1
2
3
4
Issues
– Power consumption (250 mWatts/ch)
– Ramp zero crossing induces important Jitter
QuickTime™ et un
décompresseur TIFF (non compressé)
sont requis pour visionner cette image.
Synoptic
1-Nov-07
Hwaii 2007 -N43-4
22
Direction to reach 1(few) psec (3)
Alternative to Time stretcher
– Replace the TDC ---> ADC
DC level to ADC
ADC
Digitized dt
dt
1-Nov-07
Hwaii 2007 -N43-4
23
Best results with 2 TOF counters in tandem
QuickTime™ et un
décompresseur TIFF (non compressé)
sont requis pour visionner cette image.
1-Nov-07
From J. Va’vra (SLAC)
Hwaii 2007 -N43-4
24
Diffractive Trigger
Horizontal roman pots
(a la TOTEM)
- 224 m
xA
7 plans Si /Roman Pot
 positionmicrons
 time < 5 psec
- 216 m
xB
jet
Front end
PA
SH
xA xB
T
Left
Pretrigger
T
R
jet
Right
Pretrigger
ATLAS detector
xD - xC =0
xA - xB =0
LR Trigger Logic
Pipeline
buffer
(6.4 sec)
+850 ns (air cable)
+730 ns
T
1,0 sec
• LP AND RP
•TR - TL
2,0 sec
L1 CTP
2 Jets with
Pt > 40 Gev/c
Max 75KHz
2,5sec
ATLAS standard
R
O
D
1-Nov-07
30 nov 2006
US15
Hwaii 2007 -N43-4
HLT Trigger
(ROB)
ATLAS Standard
Refined Jet Pt cut
Vertice within millimeter
D time < 5 to 10 psec
25
Timing and Data flow
BXing
0 ns
Proton @ RP
733 ns
Flight path
1024 ns
Pretrigger Data available
@ 220 m(Alcove)
Processing
Detector response 11 ns
ABCD response 150 ns
20 ms cable 80 ns
Pretrigger Processing 50 ns
RP ASIC & FPGA
SI ---> 4 Events x 2 Si Strips x 10 bit words
MCP ---> 4 Events x 6 bit words per Xing
= 104 bit/Bx
Average Rate = 4,16 Gbit/sec (11ns through cable to Alcove)
ALCOVE CTA crate PRETRIGGER
Matching 2RPs with overlap Si Strips
Add Timing information from relevant MCP PMT pixel (1 mm2))
1921 ns
RP Triigger Data @ ATLAS CTP
Cable
LVL1 ACCEPT (75 KHz)
80 bit/BX x 40 MHz = 3,2 Gb/s
80 bit @ 10 GB/s - 880 transfert time
Processing
Max
2500 ns
588 ns
5120ns
RPs data @ ROD
Cable
2x 1100 ns + 7.4 K bit @ 4x 5 Gb/s= 2620 ns
Data Production per Roman Pot to ROD
4 events x(7 Si detectors x10 bit word stored in the pipeline)
4 events x 1 MCP-PMT detector x (6 bit adress + 8 bit fine timing)
Total per LV1 Accet = 336 bit
Total x 75 KHz =25 Mb/s
1-Nov-07
Hwaii 2007 -N43-4
26
Implementation block diagram
MBP
Detector
ASIC
Local
Logic
FPGA
RP B
RP A
X X
XX XX
X X
XX XX
FPGA
FPGA
//
IP
Picosecond CLK 160 MHz
Trigger DATA
4,16 Gb/s
RO DATA
670 kb/s
RP Left Trigger
1Cable
DATA
2 x 3,2 Gb/s
CTA crate
4 fiberss
ATLAS ROD
(LVL2
DAQ)
LHC&CLK
75 KHz
25 Mb/s
Pretrigger logic
Read Out
Control & Monitoring
160 MHz CLK (fiber)
Reference clock
(Atomic)
LHC CLK
1-Nov-07
RP Right
Trigger
L1 ACCEPT
20 m
Cables
Shielded
Alcove
ATLAS
LVL1
CTP
Hwaii 2007 -N43-4
US 15
27
Conclusions
A challenging ‘small’ experiment
Need to use State of the art technologies
Tracking Silicon hodoscopes with 10 m precision
Ultra fast timing with few Psec TOF resolution
Input signals forTrigger @ L1 in ATLAS
System aspect non obvious (stability, radiation …)
But the Physics results
might be outstanding !
Thanks a lot for your attention!
1-Nov-07
Hwaii 2007 -N43-4
28