Joseph Carbone

Imaging of laser--plasma x-ray emission with charge-injection devices

This work details the method of obtaining time-integrated images of laser–plasma x-ray emission using charge-injection devices (CIDs), as has been demonstrated on the University of Rochester’s 60-beam UV OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The CID has an architecture similar to a charge-coupled device. The differences make them more resistant to radiation damage and, therefore, more appropriate for some application in laser–plasma x-ray imaging. CID-recorded images have been obtained with x-ray pinhole cameras, x-ray microscopes, x-ray spectrometers, and monochromatic x-ray imaging systems. Simultaneous images obtained on these systems with calibrated x-ray film have enabled determination of the absolute detection efficiency of the CIDs in the energy range from 2 to 8 keV.

Megarad and scientific CIDs

Nine imagers that exploit distinctive CID properties and incorporate on-chip amplifier configurations (including preamplifier/pixel) were developed for use in automation, nuclear and scientific applications. TV compatible (11 mm) formats of 768H X 575V (European) and 755H X 484V (domestic-RS170) were fabricated for radiation- hardened product cameras. Operating CIDs provided excellent signal-to-noise at radiation levels of 106 rads/hr, and accumulated dose beyond 106 rads in silicon (60Co source). Large format imagers featuring random pixel and subarray addressability, were created for spectroscopy and other scientific applications. They possess a 27 X 27 micrometers 2 pixel in 1024H X 1024V, 1024H X 256V, and 512H X 512V formats. Pixels and subarrays (even overlapping subarrays) can be read out destructively or non-destructively. The above features can be combined with 2D on- CID pixel binning because CID binning preserves the spatial fidelity of the pixel charge. Two 1024 linear-type imagers were fabricated with a preamplifier-per-pixel structure and a 27 X 150 micrometers 2 large capacity photo-site. One device features on-chip large signal differencing capability between successive exposures. Two 512H X 512V (20 X 20 micrometers 2 pixel) format imagers were created for UV photon-counting applications. The imagers provide high local count rates through video-rate random subarray addressability and subarray charge injection.

Radiation tolerant CID imager

A new European-format CID imager with improved radiation tolerance was developed to meet the operational requirements of the burgeoning international nuclear power generation and waste management markets. Incorporating an inherently radiation tolerant CID architecture fabricated using a new improved radiation resistant process, the imager is designed to survive total dose radiation of more than 106 rads (gamma-Sl) in environments greater than 105 rads/hr (gamma-Sl). The imager format is 786 pixels/row by 612 rows mapped into an 11 MM diagonal optical format. The device incorporates an 11.5 micron2 pixel structure that can be read out either in an interlaced CCIR TV compatible or progressive 25 Hz mode. Additionally, the imager incorporates a deep depletion high resistivity structure that makes it suitable for sensing x ray, nuclear as well as E-beam forms of radiation. The CID device design and tooling was completed during 1993. Sample devices were fabricated and tested during late 1993 and early 1994. Preliminary test results together with further imager and camera development plans are included herein.

Large format CID x-ray image sensors

A large format CID imager module capitalizes on CID large well capacity and radiation resistance to image dental x- rays. The model, which consists of the imager, conversion phosphor and ancillary electronics, is encapsulated in a 40 X 28 X 5 mm3 robust package that is lightproof, moisture-proof and meets FDA and RFI/EMI standards. Data exposure and readout is simple. The imager normally exists in an active reset mode until x-ray application automatically places the imager into a charge integration mode. Readout begins immediately upon completion of the x- ray exposure or manual application of an external trigger source. The imager returns to the reset mode once the data read out is complete. Pixels are arranged in an SVGA compatible 800H X 600V format. Each pixel is square and 38.5 microns/side. The imager is coated using a propriety phosphor deposition process that result in a limiting resolution of 9 LP/mm from an x-ray illumination source. Better than 2,000:1 dynamic range and shot-noise limited operation is achieved. Direct x-ray detection and attendant noise is minimized via the phosphor and epitaxial layer that lies beneath the pixel array. The imager/module architecture and electro-optical performance are described in detail here in.

Design, fabrication, and characterization of a family of active pixel CID imagers

A new type of sensor has been developed for applications in high radiation environments such as space. In this paper we present the pixel structure, fabrication cycle and measured performance of a family of active pixel charge injection devices designed in PMOS and respectively CMOS technology. A simple 8 by 8 prototype was developed in 1996. This was followed by a 40 by 54 array having 90 micrometers pixel size. This device has address decoders integrated on chip and, a transfer gate included in each pixel in order to eliminate feed-through noise. These circuits were fabricated at RIT using a 6 micrometers PMOS double polysilicon technology. A third 128 by 128 array having 41 micrometers pixel size has been designed and manufactured at a commercial foundry using 2 micrometers CMOS technology. The on-chip decoders allow resetting of selective regions of the chip.

New low-noise, random access, radiation-resistant and large-format charge-injection device (CID) imagers

New low-noise CID imagers are being created to meet the demanding requirements of scientific instrumentation, high-speed tracking and nuclear inspection applications. The imagers incorporate new process technology and/or new low-noise architectures to exploit inherent unique CID features including random pixel addressability, true non-destructive pixel readout (NDRO), two-dimensional windowing (sub-array readout), and exceptional resistance to the effects of ionizing radiation. These CID features enable the user to monitor and dynamically adapt application exposure levels in real-time, reduce noise, and read out small sub-arrays of pixels at exceptionally fast rates. Due to their radiation tolerance characteristics, the devices can operate in harsh radiation environments and actually image (detect) the incoming radiation. Device formats and performance features are summarized.

Scientific CMOS CID imagers

A new family of binary format CMOS CID imagers was designed to meet the random pixel addressing and on-chip signal manipulation requirements of may scientific applications. Key features include true random pixel and programmable subarray addressing, non-destructive readout and charge injection (clearing) that eliminate the need to read out superfluous pixels. And, programmable horizontal/vertical binning provides improved signal/noise and permits spatial signal consolidation even when reading out overlapping subarrays. The imagers incorporate on-chip preamplifiers for low noise readout. Inherent CID pixel characteristics such as non-destructive, non-blooming read-out that permit adaptive exposure control and linear dynamic range extension are maintained. Formats include 10242, 5122, and 1024 X 256. All incorporate 27.0 micron contiguous square pixels with in excess of 106 electron well capacity. Serial horizontal and vertical input ports are provided to accept the coordinates of the pixel or subarray to be readout. Rapid subarray readout is facilitated via a single pixel advance clock that is used in conjunction with each random access decoder. A description of the architecture, imager operation and application will be presented.

Selectable one-to-four-port, very high speed 512 x 512 charge-injection device

A high-speed 512 X 512 charge injection device with selectable one to four video ports has been developed, fabricated, and tested beyond the designed speed of operation. The imager has four independently controllable video ports allowing for all possible combinations. This is accomplished by having each port hard wired to one out of every four rows sequentially. Each port is selected via a multiplexer in the sequence desired. The horizontal scanner was designed to operate up to 30 MHz. The device was tested at the wafer level to 42 Mhz element rate per port. This element rate allows a maximum of 168 MHz element rate with four ports operating in parallel.

Charge injection devices for use in astronomy

Arrays of silicon sensors arranged in a CCD focal plane architecture have become the detector of choice for astronomical imaging in the 300 nm to 1 micron region. However other focal plane architectures offer attractive additional features such as allowing for random access to, and readout of, any subarray on the chip, and the nondestructive interrogation of the signal level of any pixel. A 512 x 512 pixel array utilizing a Charge Injection architecture that offers such advantages has been tested at liquid nitrogen temperature as to its suitability for use in astronomy. Laboratory tests show that using nondestructive readouts results in a (root)N (where N is the number of readouts) improvements in the noise figure (approximately 20 electrons rms noise after 100 reads). Initial images with a CID-38 of a number of astronomical objects are also presented.

Design of a large-format charge-injection-device imager for spectroscopy

A new large format (512 X 512) charge injection device (CU)) imager was designed and fabricated for use in spectroscopy and other scientific instrumentation applications. Because of its large pixel size (28 urn X 28 urn) the imager design features wide dynamic range and extended spectral response. Additionally a pre-amplifier per row read-out architecture is employed to reduce read-out noise by an order of magnitude from that of a conventional read-out architecture. Initially the imager was fabricated using a commercial oxide-nitride CD process. Eventually an all-oxide CD process will be employed to fabricate the imager. The removal of the nitride is projected to reduce further the read-out noise as well as optimize the UV response. The imager is being integrated in an existing CPU-based scientific instrumentation camera. Among the features that will be demonstrated are: wide dynamic range low read-out noise improved spectral response virtually no-blooming random-access capability true non-destructive read-out and adaptive integration time. 1.