G. Drake Electronics for Next- Generation Telescopes Oct. 21, 2005 p. 1 ARGONNE NATIONAL LAB G round-B ased G am m a R ay A stronom y: Tow ards the Future UCLA W orkshop Electronics for N ext-G eneration G round-B ased Telescopes Presented By Gary Drake Argonne National L aboratory In Collaboration With Karen Byrum (ANL ), Simon Swordy (UC), Scott Wakely (UC) Oct. 21, 2005
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ARGONNE NATIONAL LAB G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 1.
ARGONNE NATIONAL LAB G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 3 Instrumentation Concepts It is Desirable to Increase the Angular Resolution of the Images Measure Lower Energies Reduce Background Implies: Smaller Pixels 0.15° < 0.05° More Channels for Same FOV 10,000 The Technology is Here Now, and Continues to Advance: Multi-Anode PMTs Multi-Channel Plates Silicon PMTs APD’s Photo-Detectors for Next Generation Telescopes Hamamatsu H anode PMT Pixel ~(5.8mm) 2 Common in HEP, Need R&D for Future Telescopes Burle Planacon Micro-Channel Plate anode PMT Pixel ~(6mm) 2
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G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 1
ARGONNE NATIONAL LAB
Ground-Based Gamma Ray Astronomy: Towards the Future UCLA Workshop
Electronics for
Next-Generation Ground-Based Telescopes
Presented By Gary Drake
Argonne National Laboratory
In Collaboration With Karen Byrum (ANL), Simon Swordy (UC), Scott Wakely (UC)
Oct. 21, 2005
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 2
ARGONNE NATIONAL LAB
Present Photo-Detectors are Typically Single-Anode PMTs Telescope Mirrors Focus Light onto Photo-Cathodes PMT Signals are Digitized (8-12 Bits) using FADCs
Veritas: 500 MHz FADC Provides ~2 nS Timing
• The Nature of Events
Digital Calorimetry
-ray Candidate Cosmic Ray Muon
Instrumentation Concepts
Veritas Telescope 1 Images Courtesy of Liz Hayes & Veritas
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 3
ARGONNE NATIONAL LAB
Instrumentation Concepts It is Desirable to Increase the
Angular Resolution of the Images
Measure Lower Energies Reduce Background
Implies: Smaller Pixels
0.15° < 0.05° More Channels for
Same FOV 500 - 1000 10,000
The Technology is Here Now, and Continues to Advance:
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 7
ARGONNE NATIONAL LAB
Instrumentation Concepts The Pros
High-Performance Circuitry Small Size Low Power Inexpensive for
Large Quantity Production The Cons
Long Learning Curve for Tools High Cost of Tools (~$0 for
Educational Institutions) Development Time ~1-2 yrs. Need Special Test Facilities Cost-Effective Only for Very
Small Quantities (Prototype) or Very Large Quantities
• The Pros & Cons of Using an ASIC
Telescope Instrumentation Project is in On-Par with Large HEP Experiments, Where ASICs are Used Routinely
Photo of DCAL ASIC for Linear Collider Courtesy of Ray Yarema, Fermilab
Significant Capital Investment
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 8
ARGONNE NATIONAL LAB
Instrumentation Concepts• ASIC Functionality? Traditional Pulse-Height Digitization
Good Pulse-Height Resolution Complex Circuitry High-Speed = High Power Lots of Bits to Read Out Difficult to Trigger Correction Overheads: Pedestals, Calibrations, Linearity
A New Idea: Digital Imaging / Photon Discrimination (Swordy) Assume Small Pixel Size (Required) Most of Time, Single pe’s Will Hit Individual Pixels,
True For Signal, Noise, and Background Instrumentation: Each Pixel Has A Discriminator, Efficient at 1 pe
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 9
ARGONNE NATIONAL LAB
Instrumentation Concepts• A New Concept: Digital Imaging
Pulse-Height Temperature Plot Hit Map
(Artist’s Conception…)
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 10
ARGONNE NATIONAL LAB
Instrumentation Concepts• A New Concept: Digital Imaging (Cont.)
Pulse-Height Temperature Plot Hit Map
(Artist’s Conception…)
Low Energy Signals:
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 11
ARGONNE NATIONAL LAB
Instrumentation Concepts• A New Concept: Digital Imaging (Cont.)
(Artist’s Conception…)
Noise (Dark Current & NSB)Rejected by “Level 0” Trigger:
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 12
ARGONNE NATIONAL LAB
Instrumentation Concepts• A New Concept: Digital Imaging (Cont.)
Strengths in Approach: Greatly Reduced Background per Pixel Very Simple Electronics Greatly Reduces Data Volume Relatively Easy to Trigger
Simulations & Studies in Progress…
Difficulties, Additional Thoughts, Ideas, Studies: Shape of Hit Pattern as a Function of Energy? Time Over Threshold for Crude Pulse Height? Fold in View from Multiple Telescopes (Yes) Pulse Height Digitization of Dynode? Use of Out-Riggers for Pulse Height Measurement? Issues with QE, Gain Uniformity, Single pe Response…
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 13
ARGONNE NATIONAL LAB
• Basic System Requirements & Design Choices Nature of Data: Timestamp & Hit Pattern (Chip ID Appended Later) Timing Resolution: 1-2 nS Raw Data Rate: ~1 - 10 MHz per Pixel Overall Output Data Rate: ~1-10 KHz (After L0/L1 Trig) Live Time: 100% (@ Max Event Rate) Triggering:
Level 0 – 1. More Than 1 Pixel Hit in a Time Window 2. Geometrical Constraints… Level 1 – Trigger from Neighboring Photo-Detectors
Data Output: High-Speed Serial Link, Possibly Fiber Event Selection & Filtering: High-Level Triggering in Back-End, Using Timestamps and Geometrical Mapping
Instrumentation Concepts
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 14
ARGONNE NATIONAL LAB
Conceptual Design of ASIC• Front-End ASIC
Front End Amplifier & Discriminator Senses Hits Above Threshold
30-Bit Timestamp Counter Runs at 500 MHz
Comparator States Clocked into Shift Register - Buffer for Trigger Decision, 1000 Stages (2 usec)
Save States & Timestamp on Ext. Trig. or Self-Trigger
Counters Reset Once per Sec, Synchronously Across System
Serial Data Output – 100 Mbit/sec, 94 Bits/Event, ~1 uSec/Event
Serial I/O – Separate Data, Control, & Trigger
Services 64 CH
DAT
CLK
Inputs from Pixels
Amp/Discrim
Pipeline
Rea
dout
Buf
fer (
FIFO
)
1b x 1000
Clock &Control
W R
CLK
DW DR
CN
TRS
T
DataSerial Out
Dat
a O
utpu
t Driv
erC
ontro
l
Pipeline1b x 1000
Pipeline1b x 1000
Pipeline1b x 1000
Pipeline1b x 1000
TRIGOUT
Qinj
Vout
DAC
Mas
k R
egis
ter
MA
SK
Control I/O Driver/Receiver ControlSerial I/O
Trig Control
Level 1 Trig I/O Driver/Receiver
CLK
Pipeline1b x 1000
TIN
T D
LYD
EXT TRIGIN
TIN
T
Inte
rnal
Trig
ger D
ecis
ion
Logi
c
Lev
el 0
Trig
ger
FIFO
CLK
TIN
T
Out
put C
ontro
l
Dia
gnos
ticD
ata
Timing
Timestamp Counter30b
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 15
ARGONNE NATIONAL LAB
Conceptual Design of ASIC• Front-End ASIC (Cont.)
Similar in Concept to Chip Development in Progress for Linear Collider DCAL
Collaboration with FNAL ASIC Design Group
Design Work Being Done by Abder Mekkaoui & Jim Hoff
New Chip Must be Faster… 0.13 micron SiGe
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 16
ARGONNE NATIONAL LAB
Conceptual Design of ASIC• Front-End ASIC (Cont.)
Discussions with FNAL They are Interested!
Work in Progress on Establishing Another Collaboration with FNAL ASIC Design Group
Design Work Could Begin in 2006
First Stage – Develop Models, Sims, Basic Design
Proof-of-Principle for 2nd Stage Funding
Draft
G. Drake Electronics for Next-Generation Telescopes Oct. 21, 2005 p. 17
ARGONNE NATIONAL LAB
Summary• Photo-Detector Technology is Advancing, From Which Future Telescopes Can Benefit
• New Telescopes Will Need Smaller Pixels, Higher Level of Electronics Integration
• Custom ASICs Are Common Now in High-Performance Instrumentation
• Preliminary Design Work & R&D to Begin Soon
• Leverages Resources of National Labs
High-Level Integration, High Channel Count, Low Power