Figure: The Proximity Camera Head (A2047A). Marked are (1) the eight-way flex socket for connection to a TC255P Minimal Head (A2016), and (2) the LWDAQ device socket. The flex socket pin one has a square pad on the connector footprint.
| Schematic | PCBs | Assembly |
The Proximity Camera Head (A2047) is a Long-Wire Data Acquisition (LWDAQ) Device that reads out a TC255P image sensor. It is a radiation-tolerant descendent of the Inplane Sensor Head (A2036). We use the A2036 and A2033 most often with the LWDAQ Software's Rasnik Instrument
The A2047 connects to a LWDAQ driver (such as the A2037) or LWDAQ multiplexer (such as the A2046) with a LWDAQ cable. The A2047 connects to the image sensor through a flex cable. The image sensor is mounted upon any TC255P Minimal Head (A2016). The flex cable is a 1-mm pitch, 8-way flat cable. We have operated the A2047 with flex cables up to 450 mm long, but we notice an increase in image noise and some loss of contrast at such lengths. In almost all our instruments, the flex cable is less than 100 mm long.
The following versions of the A2047 exist.
| Version | Description |
| A2047A | Proximity Camera Head |
| A2047T | Inplane Sensor Head |
The Inplane Sensor Head (A2047T) has the same shape as the Inplane Sensor Head (A2036A). The A2047A is a long, thin version of the same circuit, designed for the long, thin Proximity Camera.
We designed the A2047 for use in the ATLAS end-cap muon spectrometer alignment system. The circuits read out chessboard images as part of Rasnik Instrument. For a description of Rasnik images and how we analyze them, see Rasnik Analysis.
The A2047 is complies with the LWDAQ Specification. It is Device Type 2 (TC255P) for device-dependent jobs. It ignores the device element numbers.
| DC16 | DC15 | DC14 | DC13 | DC12 | DC11 | DC10 | DC9 | DC8 | DC7 | DC6 | DC5 | DC4 | DC3 | DC2 | DC1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| X | X | X | X | X | X | X | X | WAKE | LB | ABEN | ABGD | IAGD | SAGD | SRGD | DCEN |
The A2047 does not provide anti-blooming.
The A2047 provides exposure of the TC255P with no anti-blooming. Anti-blooming is good for pictures showing where things are, but it compromises the linearity of the pixel response, and is therefore detrimental to the performance of survey cameras.
We expose the TC255P with the following sequence of LWDAQ Driver jobs: move, wake, flash, alt_move, and read. This sequence ends with the eight-bit gray-scale image in the driver memory. For a detailed description of the image read-out sequence, see the Operation section of the A2051 Manual. The A2051 readout is identical to that of the A2047, except that the A2047 does not support anti-blooming.
The A2047 is asleep when it powers up, and after a sleep job. To measure the propagation delay of signals traveling from the driver to the A2036 and back again, we execute the loop job and read the loop time out of the driver.
For more data acquisition details, see the Discussion section of the Inplane Sensor Head (A2036) Manual.
The A2047 is functionally equivalent to the A2036, but its internal circuits are more resistant to radiation than those of the A2036. Instead of a MAX6329 band-gap reference low drop-out regulator, the A2047 provides 3.3 V power with a transistor-diode regulator. Instead of waking up the ±15V supplies with a DG411 analog switch, the A2047 does so with discrete MOSFETs. The 74VHC123 remains, but when driven by a radiation-tolerant power supply, the 74VHC123 is appears unaffected by 30 krad of ionizing radiation, although we did observe one failure at 100 krad.
We are confident that the A2047 can endure a slow dose of 20 krad without failure, and without its sleep state current consumption from the +5V power supply rising above 5 mA. The A2036, on the other hand, we expect to draw 5 mA from the +5V power supply after roughly 5 krad. In the A2047, the rise in current consumption is due to damage to the logic circuits. In the A2036, the rise is due to damage to the low drop-out regulator.
For more on radiation tolerance of the A2047 and A2036 components, see Ratiation Tolerance in the A2036 Manual.
For a discussion of image geometry, and how to translate between points in the image sensor and points in the image on our computer screen, see the Image Geometry section of the TC255P Minimal Head (A2016) Manual. For instructions on finding Pin One on a TC255P, see the Pin One section of the same manual.
The A2047 provides brighter images than its predecessor, the A2036. We discuss the image quality provided by our various TC255P readout circuits in the Image Contrast of the A2036 Manual.
Note: All our schematics and Gerber files are distributed for free under the GNU General Public License.