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Electronics GRETINA Project

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Electronics GRETINA Project Requirement Document Sergio Zimmermann July 24, 2004 ANL Electronics Workshop, Schedule 1 Outline Doc Data Base Justification Document types Functional requirements List of
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Electronics GRETINA Project Requirement Document Sergio Zimmermann July 24, 2004 ANL Electronics Workshop, Schedule 1 Outline Doc Data Base Justification Document types Functional requirements List of Requirement Documents Electronics Primary Requirements Example July 24, 2004 ANL Electronics Workshop, Schedule 2 GRETINA Doc Data Base GRETINA has established a document share data base grfs1.lbl.gov/cgi-bin/private/docdb/documentdatabase Very easy to use It indexes the documents by author, subject, date, key words, etc. We encourage the collaboration to use Hopefully, a demonstration So, when the project is done all GRETINA history will be in this data base. July 24, 2004 ANL Electronics Workshop, Schedule 3 Justification Good documentation foster quality and it is a key ingredient of the quality assurance process. Show me your documentation and I will tell you the quality of your product. It also enables good communication. It enables the peer review process, where we review the requirements, specifications, design, layout, tests results, etc. before we proceed to the next step. At the same time we should be cautious to not over document. Also, as a rule of thumb we should avoid duplication. We should refer to other documents. Reason, if something change we have to change in just one place. July 24, 2004 ANL Electronics Workshop, Schedule 4 GRETINA s Documentation GRETINA is in its early stages, but some key documents are already available. Example: Preliminary Project Execution Plan. The PEP establishes GRETINA s functional requirements, deliverables, management organization (with responsibilities), preliminary schedule and cost scope, change control, etc. Other documents: requirements, specifications, design, layout, tests results, etc. July 24, 2004 ANL Electronics Workshop, Schedule 5 Summary of the Functional Requirements Detector module Number of Ge crystals 1 = 27 Number of segments 6 longitudinal 6 transverse Segment Energy resolution = 2.5 kev (FWHM) average, at 1.33 MeV Noise per segment = 7 kev (standard deviation) average at 35MHz bandwidth Time resolution = 10 nsec (FWHM) average, at 1.33 MeV Array peak efficiency = 7.2 % at 1.33 MeV Array peak-to-total ratio = 40% at 1.33 MeV Position resolution = 2 mm (standard deviation) average for E int 300 kev Digital Signal Processing Module Digitizer sampling rate = 75 MHz Digitizer resolution 2 = 12 bits Final integral nonlinearity 3 = ± 0.1% over the top 99% of the dynamic range (in Eγ) Final differential nonlinearity 3 = ± 1% over the top 99% of the dynamic range (in Eγ) Final energy/gain stability 3 = ± 0.2%/hour gain drift for? ± 5 temperature drift Trigger and Readout Readout speed = 10 MB/s/crystal Additional functionality Accommodate auxiliary detectors in the trigger and the data stream Computation Data processing rate = 20,000 gamma/s total Data storage rate = 10 MB/s Performance following Signal Decomposition and Tracking Efficiency = 5.4 % at 1.33 MeV Peak-to-total = 55 % at 1.33 MeV July 24, 2004 ANL Electronics Workshop, Schedule 6 List of Requirement Documents 1. Mechanical Subsystem (primary requirements) 1.1 Support Structure (secondary requirements) 1.2 Target Chamber 1.3 LN System 2. Detector Module 2.1 Detector Module 2.2 Test and Characterization of the Module 3. Electronics 3.1 Pre-Amplifier 3.2 Digital Signal Processing Module 3.3 Trigger and Timing 4. Computing Systems 4.1 Event Building 4.2 Event Processing 4.3 Slow Control July 24, 2004 ANL Electronics Workshop, Schedule 7 Elect. Primary Requirements 1SCOPE 2 GENERAL 2.1 Purpose 2.2 Precedence 2.3 Authority July 24, 2004 ANL Electronics Workshop, Schedule 8 Elect. Primary Requirements 3 ELECTRONICS SYSTEM PRIMARY REQUIREMENTS 3.1Front-End Segment energy resolution Noise per Segment Position Resolution Digitizer Sampling Rate Dynamic range and required resolution Non-Linearity Final Energy/Gain Stability Pre-Amp Rise Time July 24, 2004 ANL Electronics Workshop, Schedule 9 Elect. Primary Requirements 3.2 Data Readout Maximum Event Rate Dead-time Readout Speed Digitizer Information Pipeline Readout July 24, 2004 ANL Electronics Workshop, Schedule 10 Elect. Primary Requirements 3.3 Trigger Logic Introduction Maximum Trigger Latency Segment Trigger Control Segment Lower Level Threshold Segment Upper Level Threshold Trace Buffer Readout Size Trigger Options Trigger Source Selection Logic Multiplicity Trigger by Centroid or Segments Trigger Coincidence Overlap Time External Trigger Topology Trigger Future Trigger algorithm User Parameter Table July 24, 2004 ANL Electronics Workshop, Schedule 11 Elect. Primary Requirements 3.5 Auxiliary Detectors Trigger Interface Synchronization and Time Stamp Auxiliary Detectors information July 24, 2004 ANL Electronics Workshop, Schedule 12 Elect. Primary Requirements 3.6 Other Requirements Reconfigurability and Logic Expansion Cables and Detector Interconnection Board Identification Testability Data Sampling and Monitoring Energy and Timing Calibration Mitigation of Hazards Spare Components and Modules July 24, 2004 ANL Electronics Workshop, Schedule 13 Example Segment energy resolution The segment energy resolution must be = 2.5keV FWHM at an energy of 1.33MeV ( 60 Co source). Justification: Usually for Ge detectors of the GRETINA size is not unreasonable to expect = 2.5keV FWHM at an energy of 1.33MeV ( 60 Co source), with peaking times of 4-5 usec. In general FWHM 2 = Noise 2 +a*e. The first term is the noise of the electronics and the second term is due to the statistics of carrier generation. For example in Gammasphere we have Noise ~ 1keV and the E term is ~ 2keV at 60 Co. Based on our experience with the GRETA prototype (See Fig.) the quoted requirement is achievable. Note that the value at the Am line (60keV), is essentially the Noise term. Status: Firm, part of Preliminary PEP Functional Requirements July 24, 2004 ANL Electronics Workshop, Schedule 14 Example Reconfigurability and Logic Expansion The electronic system has to be reconfigurable to accommodate different data handling and processing and trigger algorithms. The ability to reconfigure the electronics has to be part of the system and should be fast to execute. Also, the reconfigurable logic must have enough spare space. Justification: GRETINA will be used in different Nuclear Science experiments, which require different hardware/firmware configurations. Firmware upgrades and revisions have to be easy to propagate through the system to decrease down time and maintenance costs. Status: Firm July 24, 2004 ANL Electronics Workshop, Schedule 15 Conclusions The primary requirement document is the next step on GRETINA. There is a very preliminary draft, we need to complete, expand, etc. This workshop is an excellent opportunity of this. Documentation is part of the process of developing a project. July 24, 2004 ANL Electronics Workshop, Schedule 16
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