Towards our SQUID electronics for TES readout Raul Hennings-Yeomans Weekly meetings UCB Weak Interactions June 21, 2013

Friday, June 21, 13

Introductory remarks •

We met with Nader to see how much we can collaborate with CDMS

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May borrow a SQUID board from them as well as room temp electronics for it. If SQUID board not available, will go to Kent Irwin.

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Probably will borrow a detector with a known Tc of 68mK to check in our setup.

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Mentioned interest in helping us doing runs (“piggybacking”) in the 75uW fridge they have equipped with SQUID electronics already.

Friday, June 21, 13

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Nader confirmed the witness sample produced at TAMU could be made a light detector with minimal fabrication touches.

Example of Phonon Readout ARTICLE IN PRESS

D.S. Akerib et al. / Nuclear Instruments and Methods in Physics Research A 591 (2008) 476–489

ARTICLE IN PRESS

487

D.S. Akerib et al. / Nuclear Instruments and Methods in Physics Research A 591 (2008) 476–489

Sensor QampBias first stage

SQUID Bias

+/+/- D-A 5VDC 5VDC converters SQUID QET Rbias Rbias 25kΩ 1k Ω Front End Board +

to second stage, driver VB

FEB ground plane RB= 1 kΩ

-5 Ω

3-5 Ω trace resistance

Rsh= 20 mΩ

150K FET window

Rtotal = 0.2 to 0.3 Input Coil

300 K

300K

RF= 1 kΩ

Ω

4K Feedback 4K

SQUID Array

Coil (1 turns)

Ground note : (10 turns) 4 QET returns run from detector to SQUET Each return is split Rs + Rp into 4stripline traces on SQUET (for clarity only one set of stripline traces is shown)

4 traces ~3Ω each. Total ~750mΩ

Stripline

~3Ω

Cu stripline traces ~3Ω

~3Ω

Rfeedback 1kΩ

FET board

4K Flyover cable 4Kclosed-loop mode if the nnel readout system. The system is in the open-loop mode if the switch is open and in the switch ispair closed. = twisted 600m K 10m K 45

10m K

40

SQUID board

Noise (pA/rtHz)

Input coil Rsh = 20m Ω

10m K

25

600mK 4K

FET board

4K

20

4K 600mK 10mK 10mK

Tower Side coax Detector 50

of the

100 250 150 200 300 Responsivity (Ω) RTFb of: (a) various components

600mK

= wirebond

Flyover cable

30

value of responsivity by locking the points on the V–F curve. Points were 15 Phonon Sensors ableand slope and the slope that is unstable Ionization 10 ype ground resonances. At each DETECTOR point, we electrode e in the flat region of the spectrum, Qo 5 Qi The results are shown in the Fig. 11, y Qi shown for clarity; Qo circuit identical orrespond to the measurements taken 0 0 and the open circles to the unstable ematic diagram showing the thermal stages that theJune noise Friday, 21,on 13 the unstable slope is

600mK

Feedback coil

35

4K 4K

Rs=100-200m!

). The total output noise, then, has only Cfeedback the SQUID noise itself and the input as 1pF input amplifier noise isRfeedback amplified by a MΩ 40MΩ red to feedback whereas the (Rfeedback(RTFb), 00pF by stray) mplified the turns ratio and the RF measuring the total output noise at Ccoupling responsivity, we can separate the two

481

= pin-socket interconnet

20mK 20mK

QET 350

4K

20mK

NIMA 591 (2008) 476-489

the ionization and (b) phonon readout circuits.

The SQUID board

ARTICLE IN PRESS

uclear Instruments and Methods in Physics Research A 591 (2008) 476–489

tors are of larger ferent connection detector interface etector holder. The mit the signals from X connector and per traces) to the connections can be he DIB is made of m thick (1-ounce) limited space, the izontal edge of the ng since the tinned edge. This feature copper plated holes aterial to expose the sulting semicylindaluminum and used or surface. which are used for tor itself is held in ds screwed onto the made tight at room Friday, June 21, is 13 cooled detector

FET Board 4 Kelvin

Stripline Connector To 300K electronics

FET Window

150K isotherm suspended between board and gusset

FET Gusset

FET enclosure and heatsink

Flyover Cable

Super conducting twisted pairs

SQUID Gusset

SQUI Denclosure and heatsink

SQUID Board 0.6 Kelvin

Tower Connector To detectors

NIMA 591 (2008) 476-489

Space in the 600mK plate

Friday, June 21, 13

To do list a) Fitting on top of fridge, feethroughs b) Wiring (6 wires/TES, NbTi from MC-600mK, constantan 600mK-300K) c) SQUID board (cold hardware) d) SQUID chip (Nader will see if we can use one of theirs) e) Front End Board for SQUID room temp electronics and rack (9U, VME) f) Mu-metal shield

Friday, June 21, 13

On top of the fridge, the fitting to standard KF •

One option is to make a hole on the blank ports that we already have and epoxy a standard KF-25 to KF-50 adapter

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Another option to buy one of these from Oxford Cryo. (quote arrived, $325/KF-50, $395/KF-40)

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If we fit the Fischer connectors (that we already have) to a standard KF we could still use them instead of the D-connectors (for example making two holes to a stantard KF-50 blank to install the Fischer feedthroughs).

$325

15x2 Pins Friday, June 21, 13

$675

Wiring: aim for 5 TES •

From Mixing Chamber to 600mK plate: NbTi, 5 TES x 2 = 10 wires

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From 600mK to 300K constantan: 5 TES x 6 = 30 wires

Friday, June 21, 13

Mu-metal shield •

In order to provide an reduced ambient magnetic field to the SQUIDs, need mu-metal shield around the OVC.

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About ~$2000 (according to Nader)

Friday, June 21, 13

Began looking at several companies that make them, but need to ask for specific quote.