Imager CCD nonlinearity

We designate CCDs using the filter (which corresponds to the row) and column. For example, the g4 CCD is the CCD in the fourth column in the row covered by the g filter. The nonlinearity plots below are grouped by filter. In these plots the filled points belong to amplifier 0, the empty ones to amplifier 1 (if applicable). The Amplifier 1 fits are dashed. The vertical dotted line is the adopted saturation level for that device; points to the right of this line are ignored in the fits.

g

r

i

z

The fits shown were to the function::

$Signal = A \times Count \times (1 + α \times f (Count / ct))$

where

α

and

ct

are fitted quantities, and

$f (x)$ = 0	for x < 1
$f (x)$ = log₁₀(x)	for x > 1.

This function represents the nonlinearity in these CCDs well.

The table below shows the the fitting parameters:

chip name	amplifier	$α$	ct	% error in slope at small count	max % error at saturation	rms % deviation over the whole range	error in the fit to Signal/Count	$χ^{2} / (d . o . f .) for fit to Signal / Count$	number of fitted points	(f/l)-1, the deviation from unity of the fitted countrate $\frac{1}{A}$ from the countrate measured from the lowest exposure two points in the data	change in sensitivity from the beginning of the measuring sequence to the end measured by comparing the low-exposure frames taken at the beginning and those taken at the end	dark level, measured with the camera shutters open but the monochromator shutter closed for the equivalent of a zero second monochromator exposure
g1	0	-0.0037	1820	0.1	-0.4	0.17	0.0004	1.6	11	-0.0001	-0.002	1598.1
g2	0	-0.0050	1349	0.2	-0.6	0.26	0.0010	5.8	13	0.0000	0.002	1116.1
g2	1	-0.0238	1380	0.9	-2.8	1.25	0.0010	4.6	15	0.0001	-0.001	1103.9
g3	0	-0.0353	2818	0.9	-3.5	1.41	0.0011	7.2	12	0.0005	0.002	1147.4
g3	1	-0.0097	2951	0.2	-1.0	0.38	0.0004	1.5	12	0.0002	0.001	1142.5
g4	0	-0.0149	4786	0.3	-1.3	0.46	0.0004	1.4	12	0.0001	0.008	1251.5
g4	1	-0.0119	2818	0.3	-1.2	0.47	0.0003	0.9	12	0.0000	0.001	1238.8
g5	0	-0.0129	2399	0.4	-1.3	0.55	0.0005	1.7	13	0.0001	0.004	1203.8
g5	1	-0.0071	1175	0.3	-0.9	0.39	0.0006	2.4	12	0.0000	0.001	1192.7
g6	0	-0.0208	4677	0.4	-1.8	0.65	0.0006	2.4	11	0.0003	0.009	1229.7
g6	1	-0.0221	3388	0.5	-2.1	0.81	0.0007	3.6	11	0.0002	0.002	1216.6
i1	0	-0.0176	4677	0.5	-1.4	0.61	0.0014	27.9	11	-0.0011	0.003	1190.4
i1	1	-0.0150	4365	0.4	-1.2	0.54	0.0012	14.9	11	-0.0009	0.003	1184.6
i2	0	-0.0274	2630	1.1	-2.4	1.21	0.0007	4.4	13	-0.0000	0.005	1183.5
i2	1	-0.0110	5888	0.2	-0.8	0.34	0.0005	3.2	13	-0.0004	0.006	1176.4
i3	0	-0.0126	3715	0.4	-1.0	0.48	0.0002	0.7	13	-0.0001	0.004	1181.4
i3	1	-0.0146	3467	0.5	-1.2	0.58	0.0006	3.8	13	-0.0003	-0.000	1175.7
i4	0	-0.0359	3236	1.3	-3.0	1.47	0.0008	8.3	12	0.0004	0.005	1063.3
i4	1	-0.0111	4467	0.3	-0.9	0.39	0.0007	7.6	12	0.0001	0.005	1055.8
i5	0	-0.0243	2188	1.1	-2.2	1.14	0.0004	6.3	11	0.0001	0.004	1890.1
i6	0	-0.0166	3802	0.5	-1.3	0.63	0.0007	8.3	12	0.0004	0.003	1090.8
i6	1	-0.0329	3311	1.2	-2.8	1.33	0.0007	7.6	12	0.0003	-0.002	1089.4
r1	0	-0.0075	1096	0.4	-0.8	0.43	0.0004	3.0	11	-0.0002	-0.005	1787.1
r2	0	-0.0371	3802	0.9	-3.3	1.36	0.0008	7.7	11	0.0001	0.004	1045.6
r2	1	-0.0316	3236	0.9	-2.9	1.25	0.0009	8.8	11	0.0004	0.005	1039.7
r3	0	-0.0285	3802	0.7	-2.5	1.04	0.0006	10.5	10	0.0001	0.012	1834.3
r4	0	-0.0063	6761	0.1	-0.5	0.17	0.0005	4.0	11	-0.0005	0.005	1103.0
r4	1	-0.0349	4169	0.8	-3.0	1.22	0.0007	4.7	11	0.0003	0.005	1090.0
r5	0	-0.0374	4677	0.8	-3.1	1.24	0.0005	3.4	10	0.0002	0.007	1144.9
r5	1	-0.0400	4266	0.9	-3.4	1.39	0.0006	5.5	10	0.0005	0.004	1134.4
r6	0	-0.0100	4571	0.2	-0.8	0.33	0.0004	3.1	11	-0.0003	0.006	1223.3
r6	1	-0.0069	2692	0.2	-0.7	0.29	0.0003	0.5	11	-0.0001	0.005	1217.6
u1	0	-0.0120	4571	0.2	-1.1	0.36	0.0005	0.7	14	0.0000	0.003	1111.2
u1	1	-0.0097	977	0.4	-1.3	0.55	0.0006	1.2	14	0.0002	0.004	1098.7
u2	0	-0.0549	10233	0.4	-3.4	0.96	0.0011	3.9	14	0.0001	0.001	2769.9
u2	1	-0.0149	6761	0.2	-1.1	0.36	0.0007	1.6	14	0.0002	0.000	2769.5
u3	0	-0.0088	1175	0.3	-1.1	0.47	0.0006	1.3	14	0.0001	0.002	1234.3
u3	1	-0.0049	1950	0.1	-0.6	0.22	0.0002	0.2	14	0.0001	0.001	1224.7
u4	0	-0.0088	575	0.5	-1.2	0.58	0.0004	0.9	14	-0.0006	-0.000	1320.0
u5	0	-0.0027	1698	0.1	-0.3	0.13	0.0006	1.3	14	0.0002	-0.000	1158.0
u5	1	-0.0019	1380	0.1	-0.2	0.10	0.0004	0.3	14	0.0001	0.002	1130.6
u6	0	-0.0261	3162	0.5	-2.6	0.96	0.0008	4.7	14	0.0003	0.001	1299.5
z1	0	-0.0156	5370	0.4	-1.1	0.50	0.0004	1.4	12	-0.0002	0.012	1147.3
z1	1	-0.0134	4786	0.3	-1.0	0.46	0.0006	3.6	12	-0.0001	0.011	1156.0
z2	0	-0.0114	5370	0.3	-0.8	0.37	0.0004	1.7	13	-0.0000	0.003	1065.1
z2	1	-0.0140	6918	0.3	-0.9	0.39	0.0004	2.1	13	0.0002	0.003	1061.2
z3	0	-0.0136	6918	0.3	-0.9	0.38	0.0001	0.1	11	-0.0001	0.006	1047.8
z3	1	-0.0093	6918	0.2	-0.6	0.26	0.0005	2.2	11	-0.0002	0.005	1046.5
z4	0	-0.0398	5623	0.9	-2.9	1.26	0.0012	9.4	11	0.0003	0.009	1066.3
z4	1	-0.0103	7586	0.2	-0.7	0.27	0.0006	3.2	11	-0.0002	0.006	1064.1
z5	0	-0.0151	6026	0.3	-1.1	0.45	0.0004	1.4	10	0.0000	0.004	1066.9
z5	1	-0.0151	5754	0.3	-1.1	0.47	0.0003	0.9	10	0.0001	0.004	1063.3
z6	0	-0.0148	6310	0.3	-1.0	0.43	0.0005	3.1	11	0.0001	0.007	1048.3
z6	1	-0.0359	4571	1.0	-2.8	1.26	0.0011	13.3	11	0.0005	0.006	1054.9

Last modified: Mon Mar 3 15:22:59 CST 2003