Upload
maurice-arnold
View
218
Download
0
Embed Size (px)
DESCRIPTION
CFT Physical Geometry 8 cylinders u Outer 6 s 2.52 m u Inner 2 s 1.66 m 16 Fiber doublet layers u 8 Axial u 8 Stereo u 1 each on each cylinder r -.2 to.51 m Axial readout to north Stereo readout to south 77,000 channels 100,000 with Central and Forward Preshower Detectors
Citation preview
DD
WBS 1.2.8:AFE II Status and Plans
Alan Brossfor the
DZero Central Fiber Tracker GroupDZero Run IIb Detector Upgrade Director’s
ReviewJuly 15, 2004
Fermilab
DD
The D0 Central Fiber Tracker
A little Background
DD CFT Physical Geometry
8 cylinders Outer 6
2.52 m Inner 2
1.66 m 16 Fiber doublet
layers 8 Axial 8 Stereo 1 each on each
cylinder r - .2 to .51 m Axial readout to
north Stereo readout to
south 77,000 channels 100,000 with
Central and Forward Preshower Detectors
DD Waveguide Bundle Routing
Routing the optical signal to the VLPCs which sit under the CC imposes some constraints.
5 sectors Each with
different fiber run
Waveguide lengths
7.7m min 11.5 m max = 8.1 m
Light Yield is a function of
Current Worst Case LY 8 pe
3-FRONT
4-FRONT
D3-G
4
B 1
5A 5B
E 3
R99.000
A2-G
5
A 2
G 5
C 3
E 4
C3-E
4
A 1
H 5
A1-H
5
B 2
F 4
123
ONE HALF CONNECTOR IN SECTOR 3 ONLY WITH FULL SHAREDCONNECTORS AT SECTORS 1 & 2, AND SECTORS 4 & 5.
4 5
B2-F
4
274
296
232
135
177
SECTORS 1 THRU 5 (5 SPLIT)CABLE ROUTES3/4 DIA. BUNDLES HELD AT R58 AND
CONTINUING ON TO THE TOP OF THE NOTCHES575eith3card.dwg
SCALE: 1/8(LOOKING AT SOUTH FACE OF CC)
B 3
H 6
B3-H
6
D4-F
5
D 4
F 5
B 5
B5-H
11
F 9
G 1 0
H 1 1
F9-G
10
D 7
E 8
D7-E
8
C 6
H 1 0
B1-E
3
C 2
F 3
H 4
D 2
C2-H
4
D2-F
3
D 3
G 4
C6-H
10
G 9
A 4
A4-G
9
E 7
G 3
H 3
G3-H
3
E2-F
2
E 2
F 2
F 8
E7-F
8
D 6
H 9
D6-H
9
C 5
G 8
C5-G
8
E 6
F 7
E6-F
7
B 4
H 8
B4-H
8
G 7
D 5
D5-G
7
A 3
F 6
A3-F
6
C 4
H 7
C4-H
7
E 5
G 6
E5-G
6
C1-D
1
C 1
D 1
E 1
F 1
G 1H 1
H 2
G 2
E1-G
1
F1-H
2
G1-H
1
C.P.S.
C.P.S.
H 1 2
H 1 3
H 1 4
H 1 5
H 1 6
H 1 7
G 1 1
G 1 2
G 1 3
G 1 4
G 1 5
F 1 0
F 1 1
F 1 2
F 1 3
F 1 4
E 9
E 1 0
E 1 1
E 1 2
D 8
D 9
D 1 0
D 1 1
C 7
C 8
C 9
B 6
B 7
B 8
A 5
A 6
H 1 8
H 1 9
H 2 0
H 2 1
H 2 2
G 1 6
G 1 7
G 1 8
G 1 9
G 2 0
G 2 1G 2 2
F 1 5
F 1 6
F 1 7
F 1 8
F 1 9
F 2 0
E 1 3
E 1 4
E 1 5
E 1 6
E 1 7 E 1 8
D 1 2
D 1 3
D 1 4
D 1 5D 1 6
C 1 0
C 1 1
C 1 2
C 1 3
C 1 3
B 9
B 1 0
B 1 1 B 1 2
A 7
A 8
A 9
A 1 0
B 1 3
C 1 4
C 1 5
D 1 7
D 1 8
E 1 9
E 2 0
F 2 1
F 2 2
F 2 3
G 2 3
G 2 4
G 2 5
H 2 3
H 2 4 H 2 5
H 2 6
H 2 7
H 2 8
B6-C
8-F
10
-H1
2E9
-G1
1
DD Visible Light Photon Counter
8 channel VLPC is used to readout fibers
QE 80% Nominal Gain =
40k But wide
distribution
DD
Analog Front-End (AFE) Readout Board
And Why We Want to Replace It
DD Analog Front-End (AFE) Board
Approximately 200 AFE boards are needed to readout CFT (&CPS/FPS)
512 channel (2/cassette) Analog output via SVX IIe Discriminator output
every 396 ns for L1 trigger
MultiChip module (MCM) SIFT chip
– Analog buffer to SVX– Discriminator output
SVX IIe
DD AFE I vs. AFE II
There are a number of problems with current AFE board that impact data taking and can significantly compromise data quality for high luminosity running
The problems with the AFE board are associated with the MCM
SVX IIe SIFT – SVX IIe interaction on MCM Functionality limitation (by design)
Threshold setting– Zero suppression (1 setting/64 ch – SVX) (Analog information)– Discriminator (14 or 18 channels per setting)
To fix this our proposal is to build new AFE boards - AFE II
No MCM New pipeline/Trigger Chip – TriP (and TriPt)
Pipeline Discriminator
Commercial FADCs for analog information FPGAs for processing
Online thresholds – one/channel (analog)– 1/16 discriminators
DD AFE I Problems
SVX Saturation At high Luminosity (high occupancy ( 30%) analog
signal for a given crossing will be reduced because of “history” in SVX front-end.
– One reset/superbunch (12 xings) Pedestal width and stability
Tick to Tick variations and problems within a tick At high luminosity discriminator firing effects
pedestal – requiring additional increase in thresholds. Quality of analog information is significantly degraded
At the Highest Luminosity expected for Run II, the degradation in the quality of the AFE analog information will significantly impact offline reconstruction and the Preshower capabilities.
Threshold increase as much as 4-5 pe!
DD AFE I Problems
Discriminator At high occupancy discriminator firing will also
impact the discriminators Threshold shift as L increases.
Compounding these problems we have VLPC and fiber issues at high luminosity (instantaneous and integrated)
VLPC Drop in gain (20%) Drop in QE (10%)
Fiber Radiation Damage induced light yield loss (10-20%)
DD SVX Pedestals vs. Accelerator Tick
Seen in all channels, effect is proportional to gain:
• Additional threshold cuts needed to suppress tick-dependent noise.
accelerator tick
Mea
n pe
dest
al 20 counts
20 counts 1.5-2pe
DD SVX Saturation
The SVX pipeline is only reset once per superbunch (12 xings)
At 30% occupancy 4 Hits integrated in pipeline “Typical” integrated charge on front end 40 pe 40% drop in Signal for “triggered” hits
Loss of signal in main pulse vs. # pe's in early pulse
-0.9-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.1
00.1
0 20 40 60 80 100 120
N' (corrected #pe 's)
rela
tive
sign
al
Relative Signal Loss
Number pe
DD Pedestal Shift- Single Channel Example
ADC spectra (from SVX) are affected by firing of SIFT discriminators
This example shows
A ped shift to the left of 1.2 pe
ADC resolution degradation
Individual pe almost gone
< 1% occup.
32% occup.
DD Pedestal Shift Global
Ped shift in 4 of the 8 MCMs on an AFE
30% occupancy Inner layer of
CFT at L 1032
Plots represent mean ped change v. channel between 0 and 32% occupancy
2-4 pe Large compared
to 8 pe Structure
MCM layout 32% occup.
DD
Physics Impact
But First – What is the light yield“If we had 100 pe/hit, I would not be
talking”
DD Light Yield
These data show LY v. for =0
Average for each supersector
“Current worst case LY” 8 pe
This is a lower limit due to SVX sat. & ADC dynamic range
Expect Axial LY Stereo LY
Axial Gain > Stereo Gain
SVX Sat. Effects smaller in Stereo
DD
The Light Yield/Signal will get worse
DD VLPC Luminosity Dependent Effects
As luminosity goes up VLPC QE and gain drop
0, 10, 20, 30, 40 % occupancy(expect close to 40% on inner layers at highest RunIIb L)
10% drop 20% drop
QE Gain
DD Fiber Radiation Damage
Dose CFT L1 2 fb-1: 10 krad 30 fb-1: 150
krad 90 fb-1: 450
krad
Represents attenuation length change
0 fb-1 : 5.0 m 2 fb-1 : 3.8 m 30 fb-1 : 2.7 m 90 fb-1 : 2.1 m
Michigan Radiation Test Summary
0
0.2
0.4
0.6
0.8
1
1.2
0 200 400 600 800 1000 1200
Dose Received (kRad)
Rel
ativ
e Li
ght I
nten
sity Cyano HBT
3HF Run II3HF Run I
DD
So, What do we Conclude about Physics Impact
Complicated, but…
DD CFT Data Quality at High Luminosity
Degradation/loss of analog information Tracker
Offline tracking with analog information significantly degraded Efficient tracking may only be possible with discriminators
No chance of using pulse height to help tracking Point set resolution Cluster “splitting”
– MC indicates that the analog information should help– Have not been able to demonstrate this with data– Even at low luminosity, AFE board analog information affects this
capability Central and Forward Preshower Detectors
Potential degradation of analog information could be crippling These may become “Digital” devices
Even if we accept all of the above – IMPACT STILL LARGE On Physics to Tape (NO RECOVERY POSSIBLE) On Manpower needed to make the most of the
tracking/preshower data
DD One Physics Example Silicon Track Trigger Impact on Higgs
Red curves High/Low LY limit
03 Black
High/Low limit 06 Discriminator Hit
efficiency drop due to threshold shift (025% occ.)
94.5% 91% 8 out of 8
63% 47% Zh case
h bb 20% Loss in STT
“tagged” Higgs evts
AFEII recovers this No Threshold shift
Sing
le-H
it ef
ficie
ncy
Discriminator Threshold (pe)
DD
AFE II Status
The Sequel
DD AFE II
Progress on AFE II is covered in D0 Notes 3898, 4009, 4076, 4233, 4497, 4500
3898 “Design of the new MCM” 4009 “MCM II and the Trip Chip” 4076 “Characterization of the TriP Chip Running at 132
ns Using a modified AFE board” 4233 “System tests of the new electronics for the CFT
and Preshower Detectors” 4497 Z-coordinate Measurement in the CFT and the
Track Search” 4500 “Problems with the AFE operation at high rates”
Also AFE II proposal and AFE Design Specification documents
This information is in your handouts
DD AFE II
A Tremendous Effort has already gone into AFE II
PPD EE DepartmentJohn Anderson
Jim HoffAbder Mekkaoui
Paul Rubinov
D0 Alan Bross
Juan EstradaCarlos GarciaPeter Hasiakos
Bruce HoeneisenMarvin Johnson
Mike Utes
DD AFE II AFE II
Full New set of boards No SIFT No SVX – Much simpler architecture Will use instead
Trigger Pipeline Chip: TriP (or Tript - more in a bit)– Discriminators and analog pipeline– TriP chip submission was very successful – meets spec.
Commercial Flash ADCs + FPGA for analog information Integrates completely with existing system
Will Have No Front-end saturation problem
– Reset once per crossing– Also allows for data taking in abort gap (cannot do presently with
AFE I)• VERY useful for Calibration studies
Improved Ped dispersion and stability– Lower and tighter threshold setting capability
• Channel by Channel - analog Improved reliability Improved readout flexibility
– Decreased deadtime– Multi-buffering possible
• CFT Readout may dominate L1 readout rate without multi-buffering Added Functionality with new submission of TriP Chip - Tript
– z information from timing ( 2 ns rms)
DD TriP
The existing TriP ASIC (7000 die on hand) Lots of testing done over last 2 years
DD AFE II –TriP Performance
Measurements on TriP very promising
Noise at 1/5 pe rms Threshold setting at 1.5
pe reliably Very high quality Analog
Data Plot at right was obtained
after 1 day of work on a TriP modified AFE board
To get this good, a plot with the AFE took about 1 month of dedicated work by the same people!
BLACK – DATA RED – FIT
All Discriminators Firing!
DD AFE II – TriP Discriminator Performance
Upper plot Red – all data Blue same data
with threshold and discriminator fires
Black – fit Lower plot
Ratio of analog data with and without discriminator fires (threshold set)
30% occupancy
DD TriP-t: the new idea
About 1% additional components:(time to amplitude converter)
7 bits t-info offline: 120ns full scale=> 2ns time => ~30cm resolution in Z
DD AFE II - TriPt
With a rather simple modification to the TriP design – time stamp for hits can be obtained
Current TriP Electronics resolution was
determined to be 400 ps For 8 pe signal expect
about 2 ns sigma Z measurement – 30 cm
Has impact on reco time and cluster splitting
In Z +15 min bias MC 40-60% reduction in reco
time D0 Note 4497
Improvement in clustering algorithm utilizing z info also a possibility 400 ps intrinsic resolution
DD TriP-t prep work
Bench testing
New package
DD TriP-t current status
The chip designers are chip designing. Ready for submission 23 Aug ’04 The new chip is the “critical path” item for
the project Some prep work going on now
We will need new packaging We had some concerns about features
used on the new chip, but not used on the old (current!) TriP chip, so we are retesting some things.
DD AFE II - Cost and Schedule
Full Project Plan Now Available
DD AFEII Prototype - current status
Schematic design is 100% complete. Internal review was held in early May. Layout of the board is about 90% complete. All parts are here. Req’s for boards are in the system. RFQs for stuffing are on the street. Firmware about 75% complete.
DD AFE II – Cost and Schedule
Cost M&S: Production cost M&S are based on quotes for parts and labor –
contingency estimate is grounds up: Manpower
Estimates from AFE experience Schedule critical path is the Tript chip Completion for the 05 Shutdown is not likely Planning for adiabatic Installation
AFE I and AFEII mixed running Will need to test compatibility once AFE II prototypes are ready
(9/04) Installation will have to be done at the crate level (16 boards)
because of difference in power requirements for AFE I and AFE II Credibility of installation plan is dependent on prototype tests
How quickly they come up Platform test and integration with trigger Software readiness Physical Installation can occur quickly (8 hour)
DD AFE II Milestones
AFE II Prototype under test 9/04 Tript MOSIS submission 9/04 D0 Internal Review 1/05 Director’s Review 2/05 Tript production submission 3/05 AFE II pre-Production 7/05 AFE II production 9/05 AFE II production complete 12/05 First Board Ready for installation 2/06
DD Conclusions – Improvements with AFE II
AFE II will Improve noise floor and pedestal stability which will allow for
consistent and reliable threshold setting with no discriminator feed-through or discriminator threshold shift
Will increase physics trigger efficiency Potential for better hit efficiency and point resolution Maintain capability of Preshower Detectors
No Front-End Saturation problem (reset once per crossing) Added functionality of the Tript (z information)
Large reduction in reco time Possible improvement in cluster finding
– Cluster splitting leading to additional improvement in track quality Readout architecture much more flexible
Less deadtime Multiple buffers can be added to greatly increase L1 capability
Board construction is simpler, more robust No MultiChip modules (MCM) Mostly commercial parts/standard mounting techniques Repairs/rework MUCH easier than in AFEI
AFEII will improve our capability to maintain high-quality and stable operation as the Tevatron Luminosity increases in RunII. This will allow D0 to maintain excellent tracking, trigger, and Preshower performance