2015/09/25 (Friday)

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	Current setup: iZIP mode, DIB1/2/3 → cables → NO filters → DCRC55/33/50.
	Overnight: Cf activation. Tower temperature stable.
0855	Fill LN cold trap Dewar
0900	Tower/MC(H35)/MC sensor/Cold Plate = 31.1/25.4/41.3/159 mK, Still = 1.39 K / 0.080 mbar, G1/G2 = 160 mbar, 1K Pot = 1.73 K / 22 mbar, Main bath = 73.3%
0905	Remove Cf source from fridge
0915	Perform “mini IbIs” calculations, observing phonon baseline voltages at varied QET biases: the standard bias and two large biases:

		Vo (250 μA)	Vo (300 μA)	Ibias (μA)	Vo (Ibias)
DIB 1	pA	-0.712	-0.7392	114	-0.7015
	pB	-0.142	-0.183	127.1	-0.216
	pC	-0.1205	-0.155	117.8	-0.1355
	pD	0.116	0.1185	100.8	-0.1805
DIB 2	pA	0.280	0.1875	-112.6	0.153
	pB	-0.392	-0.4425	-108.0	-0.487
	pC	-0.646	-0.703	-138.9	-0.8215
	pD	-0.846	-0.8945	-97.7	-.911
DIB 3	pA	0.156	0.125	100.5	0.117
	pB	-0.201	-0.2345	100.7	-0.2445
	pC	-0.143	-0.178	92.5	-0.147
	pD	0.059	0.0605	119.1	-0.376
note: for DIB2 (RevC) -250 and -300 μA were used

Purpose: We don't know what the TES resistances are with the filters removed. We used the same QET biases as we have been using with the filters, but we know the TES will be at a different place in its transition when the filters aren't there. The noise data we took will be easier to interpret and compare to noise data with the filters if the TES resistances are known.

Method: We can calculate the resistance by simply taking three data points of an IbIs curve. Measure V_bias, V_250, and V_300. These are the phonon baseline voltages at QET biases of the standard bias, ±250 μA, and ±300 μA (+ for RevC.1, - for RevC). For RevC.1, the V vs I slope is negative, which is unphysical, so first multiply all RevC.1 baseline voltages by -1. Then calculate

V_offset = 6×V_250 - 5×V_300

this is just an extrapolation of the normal-resistive part of the curve back to I=0 to get the offset. (Presumably 250-300 μA is in the resistive region, but this may not always be true.) Next calculate

R_tes = R_shunt × [ R_fb×G_total×I_bias/(V_bias-V_offset) -1 ]

where R_shunt=0.02 Ω, R_fb=1233 Ω, G_total=10.5×(2 for RevC.1, 5 for RevC)×(output gain).

Results:

Derived TES resistances (Ω)
	DIB 1	DIB 2	DIB 3
pA	0.45	0.227	0.248
pB	0.216	0.382	0.227
pC	0.305	0.371	0.248
pD	0.164	0.391	0.124
italicized cases seem to be in error.
Slope was very small, so possibly
250-300 μA was not high enough.

0932	Finish “mini-IbIs” for all channels in no-Filter iZIP setup.
1022	Unpower DCRCs. Repower with filters in place: Ebox → cables → Gender swaps → filters → DCRCs.
1028	Zap and set SQUIDs.
1116	Had to change driver offsets for DCRC50 for some reason. Other board setups worked fine. Set phonon thresholds to values in table below.

Phonon Thresholds
	A	B	C	D
DIB 1	40	40	45	45
DIB 2	35	35	35	35
DIB 3	45	55	50	50

1124	Do 30 minute bake in preparation for charge studies.
1158	Stop flashing.
1337	Investigate charge breakdown after bake. Observe DIB 1 pulses while increasing Side 1 Q Bias.

Side 1 Qbias	pA baseline	pB baseline
0	-0.8	-0.93	Quick Jump and return
-8			Slower return
-11	-0.79	-0.92	Elevated slightly
-13	-0.75	-0.88	Dramatic jump elevated more
-14	-0.72	-0.84
0	-0.8	-0.93
6	-0.79	-0.9	Jumps and settles slightly higher.
9	erratic baseline	erratic baseline	Noisy pulses, breakdown
10	Definite breakdown

	Bringing Qbias to a higher value, then dropping down seems to make the lower value less noisy than it would have been on the increasing slope.
1355	Investigate charge breakdown on Side 2. Again we see hysteresis.

Side 2 Qbias	pA baseline	pB baseline
0	-0.8	-0.95
-6			Jump and settle
-8			Erratic baseline
-10	-0.7	-0.93	Goes normal: ~ 1sec, then jagged: ~ 15 sec, then erratic.
-12			Normal: ~5 sec, Jagged: ~60 sec.
-14			Normal: ~10 sec, Jagged: ~2 min but diminishing.
0	-0.8	-0.95
6			Baseline erratic already.
8			Normal: ~8 sec, Jagged breakdown.
6			Fine.
12			Normal: ~60 sec, Jagged.
8			No sign of breakdown.
14			Superbreakdown.
13			Baseline only slightly erratic.

1430	Side 2 increase first to 14V, wait a few seconds then down to desired bias.

Qbias Side 2	Baseline shift in pA	Notes
+14 V → +10 V	none	looks fine
+14 V → +12 V	none	looks fine
+14 V → +13 V	+0.1 V	baseline unstable, some weird shapes that go away.
-14 V → -12 V	none	looks fine
-14 V → -13 V	none	looks fine
-14	+0.05V	baseline settles a bit with time

1440	Side 1 increase first to 14V, wait a few seconds then down to desired bias.

Qbias Side 1	Baseline shift in pA	Notes
+14 V → +10 V	none	looks fine
+14 V → +12 V	+0.1 V	some jagged distortions
+14 V → +11 V	none	low amplitude, jagged distortions just above white noise
+14 V → +13 V	+0.18 V	jagged noise
+14 V	+0.18 V	jagged noise, still some pulses but maybe only large ones
-14 V → -12 V	none	looks fine
-14 V → -13 V	none	looks fine
-14	none	looks fine

Qbias Side 1	Qbias Side 2	baseline shift DIB1 pA	notes
-14 V → -12 V	+14 V → +12 V	+0.08 V	some jagged noise
+14 V → +10 V	-14 V → -10 V	none	looks fine
+14 V → +12 V	-14 V → -12 V	none	hint of jagged noise

1535	Flash 30 s to neutralize crystal.
1625	Place Ba source inside top most part of shield on back of fridge for 15 minute Barium run.
	Set phonon thresholds to 65 bins across all boards.
1633	Start Ba data: -/+4 V Bias, 15 mins run , 1000 randoms, 3.2768 tracelength
1655	Return Ba source to safe.
1738	Start DAQDAQ: 8 cycles of -/+4 V Bias, 15 min run/6 sec flash/ 30 min cooldown with no external sources.
1754	Fill LN2 cold trap full.

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