1 / 17

Instrumentation Concepts

g -ray Candidate. Cosmic Ray. Muon. Instrumentation Concepts. The Nature of Events. 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.

luz
Download Presentation

Instrumentation Concepts

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. g-ray Candidate Cosmic Ray Muon Instrumentation Concepts • The Nature of Events • 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 • Digital Calorimetry Veritas Telescope 1 Images Courtesy of Liz Hayes & Veritas

  2. Instrumentation Concepts • Photo-Detectors for Next Generation Telescopes Hamamatsu H8500 64 anode PMT Pixel ~(5.8mm)2 • 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: • Multi-Anode PMTs • Multi-Channel Plates • Silicon PMTs • APD’s Burle Planacon Micro-Channel Plate 85011-501 64 anode PMT Pixel ~(6mm)2 • Common in HEP, Need R&D for Future Telescopes

  3. Instrumentation Concepts • Photo-Detectors for Next Generation Telescopes Teststand at Argonne

  4. Instrumentation Concepts • Photo-Detectors for Next Generation Telescopes • High-Density Photo-Detectors Will Require High-Density Electronics • More Circuitry per Unit Volume • Short Connections to Detector to Enhance Performance • “Level 0” Triggering - Zero-Suppress at Front End • Data Stream Out to Back-End • Need Low Power • High Channel Count The Present: Front-End Electronic Packaging for HESS • Circuitry On-Board Photo-Detector The Future: Front-End Electronics Mounted on Base • Need forCustom Integrated Circuit

  5. Instrumentation Concepts • Application-Specific Integrated Circuits (ASICs) • Mature Technology • ASICs Have Been Around Since Mid-1980’s • 7 micron  0.12 micron • CMOS, Mixed Bipolar/CMOS, Silicon Germanium, Gallium Arsenide • Multi-Project Submission Services Cater to Teaching & Prototyping  MOSIS • Foundries Cater to Production • Relatively Inexpensive

  6. Instrumentation Concepts • The Pros & Cons of Using an ASIC • 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 Photo of DCAL ASIC for Linear Collider Courtesy of Ray Yarema, Fermilab • Telescope Instrumentation Project is in On-Par with Large HEP Experiments, Where ASICs are Used Routinely • Significant Capital Investment

  7. 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

  8. Instrumentation Concepts • A New Concept: Digital Imaging Pulse-Height Temperature Plot Hit Map (Artist’s Conception…)

  9. Instrumentation Concepts • A New Concept: Digital Imaging (Cont.) Low Energy Signals: Pulse-Height Temperature Plot Hit Map (Artist’s Conception…)

  10. Instrumentation Concepts • A New Concept: Digital Imaging (Cont.) Noise (Dark Current & NSB) Rejected by “Level 0” Trigger: (Artist’s Conception…)

  11. 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 • 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… • Simulations & Studies in Progress…

  12. Instrumentation Concepts • 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

  13. 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

  14. 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

  15. Conceptual Design of ASIC • Front-End ASIC (Cont.) Draft • 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

  16. 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

More Related