SOLICITATION NOTICE
59 -- Germanium Planar 100 Pixel Detector
- Notice Date
- 9/24/2007
- Notice Type
- Solicitation Notice
- NAICS
- 335999
— All Other Miscellaneous Electrical Equipment and Component Manufacturing
- Contracting Office
- Department of Energy, Stanford Linear Accelerator Center, SLAC, 2575 Sand Hill Road, Menlo Park, CA, 94303, UNITED STATES
- ZIP Code
- 00000
- Solicitation Number
- Reference-Number-134573
- Response Due
- 9/28/2007
- Archive Date
- 10/13/2007
- Point of Contact
- Gordon Scrimger, Group Supervisor Contract Administration, Phone 650-926-2612, Fax 650-926-2000, - Gordon Scrimger, Group Supervisor Contract Administration, Phone 650-926-2612, Fax 650-926-2000
- E-Mail Address
-
scrimger@slac.stanford.edu, scrimger@slac.stanford.edu
- Description
- STATEMENT OF WORK Background and Specifications for Germanium Planar 100 Pixel Detector Background. SSRL is a National synchrotron radiation user facility that provides state-of-the-art instrumentation on high-intensity beam lines for a large community of scientific users. In the area of x-ray absorption spectroscopy (XAS), SSRL operates six hard x-ray experimental stations fully or partially dedicated to this technique, and provides the needed end station equipment (cryostats, detectors, data acquisition hardware and software, etc.) for the performance of the scientific experiments. XAS is a unique tool in that it can be used to determine accurate, atomic-level, structural information that is element specific for the samples under study. The most demanding applications involve very dilute samples under naturally occurring conditions, in particular metalloproteins. Due to the extremely low concentration of the elements of interest in the samples, the studies can only be performed by measuring the x-ray fluorescence produced by the sample. The ability to make these measurements depends critically on using high-energy-resolution, high-throughput (count-rate) solid state detectors, as has well been demonstrated at SSRL and other synchrotron laboratories worldwide. In order to reach the required sensitivity for the measurements, the detector needs to be able to resolve the fluorescence signal from the inherent background of elastic and inelastic scattering, as well as the fluorescence from other nuclei in the sample. Hence excellent resolution is an absolute requirement (for most experiments 300-400 eV at high count-rates and low electronics shaping times). This can only be achieved in any commercially supported robust technology by utilizing solid state detectors. Solid state detectors are, however, inherently count-rate (throughput) limited. Total count-rate limitations are overcome by integrating a number of small detector elements into arrays, with as high a number as technically feasible. Since the fluorescence signal is isotropically distributed it is essential to collect as much as solid angle as possible, which again is made feasible by arraying many detector elements together in as closely packed arrangement as technically feasible. SSRL has since early on followed detector developments very closely and strived to obtain and provide the highest performance detectors available for XAS measurements at any given time. We have implemented, in succession, 13-element and 30-element detectors, based on individual-element packing technology. These detectors, which have all been manufactured by Canberra Industries, have performed excellently and to specification, proven robust and generally been continually in use 24 hrs/day, 7 days/week, 9 months/year. These detectors are also in use at other synchrotron facilities in the USA (NSLS at BNL, APS at ANL) and abroad (ESRF, France; Photon Factory, Japan; CLS, Canada). Some of the SSRL detectors are well beyond their expected ?life-time?, and all of them are challenged in performance by the new capabilities provided by the SPEAR3 accelerator upgrade. With SPEAR3 soon expected to increase its current to 500 mA operations a significant enhancement in detectors is required. Current Request. This statement of work thus describes a solid-state fluorescence x-ray detector that will be used for XAS measurements of ultra-dilute biological samples on SSRL?s beam line 9-3, which is a highest-performance world-class biological XAS beam line. The approach and performance requirements for data collection necessitate the specifications described below, and funding has been provided for the procurement as part of the peer-reviewed SSRL Structural Molecular Biology program. The requested detector addresses the count-rate and other performance issues through the division of the active detector area into a much larger number of smaller-sized elements (100), at the required high energy resolution per element, enabling very high total detector count-rates. Furthermore, in order to achieve the required count-rates for the experimental setup, the detector needs to be positioned as close as possible to the sample, which requires a narrow front end, and therefore the highest possible close packing of the 100 elements. This can only be achieved by the use of a monolithic detector array, i.e. an array of individual detectors fabricated close to one another on a single germanium crystal, as opposed to packing individual elements together. (The choice of germanium as crystal material is dictated by combined elemental stopping power and energy resolution requirements.) A monolithic detector eliminates the ?dead space? between individual detector elements in a conventional detector array. It therefore provides the highest collection efficiency in area coverage, within the smallest possible area, meeting both detector performance and geometric requirements. Requirements for the Detector System The following specifications are required: 1. Solid state germanium detectors are required for the energy range to be covered (5-35 keV) in the XAS measurements. 2. A monolithic detector is required for the maximization of total count rate and for a minimum front end size, to enable close proximity to the sample and intersection of the maximum number of x-ray photons. 3. The array shall have 5x5 mm sized pixel elements, close packed into a 10x10 square element array for a total of 100 elements, with 99% of the total area to be active with no dead zone. 4. The detector front-end needs to be enclosed in a circular enclosure, with diameter and length requirements as specified on the attached drawing. 5. The detector front end shall have a Be entrance window of highest-purity, 125 micrometer thickness, with a 70-mm diameter size. 6. The energy resolution performance for the pixels, measured using XIA electronics (see below) should be: Typical performance at 6 keV: At 1 ?s shaping time: 165 eV At 0.5 ?s shaping time: 200 eV At 0.25 ?s shaping time: 250 eV At 0.125 ?s shaping time: 300 eV Guaranteed performance at 6 keV of: At 8-12 ?s shaping time, 1000 cps: FWHM <145 eV At 0.5 ?s shaping time, 100 Kcps: FWHM <235 eV At 0.125 ?s shaping time, 100 Kcps: FWHM <400 eV Average performance at 6 keV of: At 0.5 ?s shaping time: 230 eV At 0.125 ?s shaping time: 350 eV 7. More than 95 pixels to be active More than 90 pixels to meet the resolution specifications 8. The detector shall be cooled by an integral liquid nitrogen cryostat with a dewar capacity of 30 liters. 9. The liquid nitrogen dewar shall be vertically attached to the detector. 10. The detector system shall be supplied with 100 pre-amplifiers of performance/design to match the specifications above, and to be compatible with and provide required performance with X-ray Instrumentation Associates (XIA) Digital X-ray Processors (DXPs), model DXP-xMAP. 11. A high-voltage power supply and pre-amplifier power supply that meet the requirements of the detector shall be provided. 12. A LN2 monitor and control system for high-voltage cutoff shall be included. 13. Complete standard cable set to be included. Final cable length requirements to be decided latest by 1 month before delivery after communication between vendor and end-user. 14. The detector system shall be provided with mounting points on the underside of the dewar and front-end and a base support. 15. Initial performance tests to be performed at the factory with XIA electronics. Final performance tests to be performed at the Stanford Synchrotron Radiation Laboratory using XIA electronics. 16. The vendor shall have extensive experience with the manufacturing of monolithic germanium detectors, of a high number of detector elements, for synchrotron radiation-based XAS measurements, and a strong demonstrated ability to provide support (service, maintenance, repair/refurbishment as per operational needs) for the detectors that they manufacture. 17. Final drawings of system shall be provided to SSRL and approved prior to assembly.
- Place of Performance
- Address: 2575 Sand Hill Road, Menlo Park, CA
- Zip Code: 94025
- Country: UNITED STATES
- Zip Code: 94025
- Record
- SN01418827-W 20070926/070924223223 (fbodaily.com)
- Source
-
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