EEV2 CCD42-80-5-904 TEST SUMMARY ******************************** Updated 9/3/01 Started 7/3/01 J.R.BARTON eev2_test_summary.txt This is the grade 1 contract device (graded to PRJ's revised specs), received from RGO on 10/11/98. It has serial number 7461-16-7 and A6284 marked on the CCD header. On the box is marked N/C 145477. This device is reputed to be one needing a high VOD bias. VITAL STATISTICS **************** - 2048 (H) x 4096 (V) pixels (+4 unused V) - 13.5 x 13.5 micron pixel size - 27.6 x 55.2 mm image area - thinned, high QE device FINAL TEST RESULTS. ******************* 1. FINAL READOUT NOISE, GAIN AND LINEARITY SPEED INT GAIN RON ALPHA SAT'N READ RATE # READOUT TIME (sec) (us) e/ADU e-rms Ke- (us/pix) full 2*2 bin 5*5bin 10E6pix NONASTRO 1+1 6.8 8.2 1.16 200 7.5 69 30 11 51 FAST 2.5+2.5 2.7 4.4 0.59 168 11.5 105 43 15 69 NORMAL 5+5 1.3 3.4 0.35 81 16.5 150 54 17 76 SLOW 20+20 0.32 2.7 0.11 21 46.5 416 123 31 121 # readout time includes a reasonable overscan. The times are those calculated by Observer software - full is a 2120 pixel (incl 72 pixel overscan) by 4096 rows unbinned - 2*2bin is 1060 binned (by 2) pixels (incl 48 overscan bins) by 2048 binned (by 2) rows - 5*5bin is 424 binned (by 5) pixels (incl 14 overscan bins) by 420 binned (by 5) rows - 10E6pix is a strip 250 pixels wide down the centre of the CCD plus 50 overscan pixels per row by 4096 rows all unbinned 2. SERIAL AND PARALLEL CHARGE TRANSFER EFFICIENCY No direct measuremts have been made. Cosmic rays appear very crisp with no smearing detected either in X or Y. It is clearly an excellant performer - the manufacturer measured the serial CTE as 0.999998 and the parallel CTE as 0.999997 3. DARK CURRENTS Dark current is only detectable in binned images and then only if account is taken of the clock induced dark currnet - the latter dominating in short exposures. The dark current generation rate is about 0.15 e-/pix/2000sec or 0.27 e-/pix/hour. This is negligible unless exposures are longer than 500 seconds and a binning of 8 or more pixels is used. 4. CLOCK INDUCED DARK CURRENTS Although only detectable in binned images (eg 5 x 5 binning), clock induced dark currents are comparatively strong on this CCD. The charge build-up is uniform across the CCD and independant of exposure time. It amounts to about 0.10 to 0.12 e-/pix, so is negligble unless binning more than 20 pixels together. It dominates shorter exposures if the CCD is properly cleaned out, i.e. not recently powered on. 5. HOT PIXELS Hot pixels seen in bias frames are located at COL ROW INTENSITY (e-) 114, 710 350 1842, 1525 1130 1539, 2152 200 Hot pixels seen in a 100 sec dark frame were located at COL ROW INTENSITY (e-) 525, 8 40 521, 28 80 114, 710 630 442, 1391 60 453, 1512 100 1842, 1525 40000 1846, 1524 160 1514, 1586 60 1320, 1655 35 509, 1771 65 1539, 2152 310 429, 2324 40 516, 2371 36 1219, 3178 60 420, 3301 40 491, 3680 80 455, 4091 600 Clearly other hot pixels will be seen in longer exposures - perhaps a hot pixel log should be started to add to this list. 6. HOT COLUMNS The hot pixel at (1842, 1525) generates a faint hot column of about 10 e-/pix as the rows are shifted through the hot pixel during the readout. Thus the hot column appears only on the "far" side of the hot pixel and extends right through to the last row of the readout. No other hot columns have been detected. 7. STITCHING LINES Regularly spaced lines appear across flat-fields. These occur every 512 pixels at the boundaries of the stitching - the process employed in the manufacture of these large CCDs. Each line appears as a pair of rows, one brighter and one fainter than the average for the flat field. The worst pair exhibits a row about 1% brighter and the next row about 4% fainter than the average, i.e. a 5% p-p effect. Hopefully these will flat-field out. This worst pair, in fact, form a limit to the full well for the CCD as this pair had a weaker charge handling capacity than the remainder of the CCD. 8. LIGHT EMITTING DEFECTS None has been detected. 9. TRAPPING SITES There are several trapping sites on this CCD but they are relatively small. They were detected by looking for delayed charge extending into the vertical overscan region. Trapping site "depth" was measured by estimating the number of pixels in the dark columns trailing the trapping site and calculating the lost charge. Traps were located and measured in a faint flat-field of 36 e-/pix as follows: COL ROW DEPTH (e-) 114, 701 240 369, 1248 350 602, 3430 1000 919, 428 400 1318, 278 100 1539, 2153 150 1723, 1399 250 10. RESIDUALS Tests were made for the residual cleanout rate by overexposing a small area of the CCD by a factor of 10 times saturation level, i.e. 2Me-/pix, and then taking a series of 100 sec exposures starting 30 secs after the end of the saturating exposure. This test indicated that the residuals accumulated at a rate less than 1 e-/pix/2500sec after 30 seconds and at 4 minutes were undetectable in a 5*5 binned image. Thus, on this chip, residuals from non-saturated images or from saturating overexposure should not be a problem. 11. SATURATION STRIPES No untoward striping in the row direction has been detected on bright saturating images. However, tests were restricted to large regions of saturation rather than saturating points of illumination. 12. POWER-ON CLEANOUT Power-on recovery was measured using 100 second, 5x5 binned, dark frames following a 30 second power-down on the cooled CCD. The recovery was as follows (with clock induced charge subtracted): TIME AFTER DARK CURRENT POWER ON e-/pix/2000sec 30 secs 123 5 min 12 10 6.3 20 2.9 40 1.3 60 1.2 80 0.7 100 0.5 16 hours 0.35 Conclusion: This CCD recovers rapidly compared to others. After 1 hour the dark current rate is down to about 1 e-/pix/2000sec compared with the MITLL CCDs which require 8 hours to get to this level. OTHER IMFORMATION ***************** 1. QUANTUM EFFICIENCY No measurements have been made but the following data was provided on the manufacturer's test sheet. The temperature of the CCD was not stated. Quantum Efficiencies (%) at spot wavelengths (nm) nm 300 350 400 500 650 900 QE 25.0 35.9 73.2 91.7 86.2 30.1