UMICH-2015: Instrumentation I break-out session 2
Goals: Analyze technology status and progress needed to read out direct detectors on the scale of CMB-S4. Please note that direct coherent amplification of CMB signals (with HEMT or other amplifiers) is covered in the detector session.
- Identify requirements for CMB-S4 polarimeter readout electronics, including both cryogenic and room-temperature components
- Review status of existing technologies with particular attention to assessing feasibility for scaling to the total pixel count of CMB-S4 (order of 500,000 total across multiple platforms) and cost
- Identify work that needs to be done in order to complete maturation of candidate technologies.
Please come prepared to describe readout techniques for CMB detectors as described above. If you have a slide to add, please post it on the wiki. If you think of additional questions or topics for debate, please add those as well.
Top-level requirements for discussion
- O($100 / pixel) is too much
- O($10 / pixel) is about right
- O($1 / pixel) is past the point of diminishing returns to CMB-S4, and may not be worth the R&D cost
Noise lower than the sensor
Cryogenic components scalable to O[500,000] sensors
- Physical size of filter and readout components
- Power dissipation per pixel
- Focal-plane interconnects
- Can wirebonds from each pixel out of the focal plane work for CMB-S4?
- Bump-bond hybridization?
- On-wafer multiplexing elements? (LC resonators coupled to TESs or MKIDs)
- Number of wires to 4K
- Number of wires to 300K
- Nearest neighbor
- Distant pixel
Room-temperature electronics scalability
The path forward
Statement: we have two mature readout techniques: TDM and FDM.
- Is the fabrication scalable in both of these techniques?
- Can the cost be scaled?
- Can the wiring be scaled?
Statement: we have 4 next-generation readout techniques at different levels of maturity: Microwave SQUIDs, KPUPs, Microwave resonator TESs, MKIDs
- These techniques have advantages in scaling and cost
- How much do we want to push to next generation techniques for CMB-S4?
CMB Polarimeter cryogenic multiplexer technology
- Time-division multiplexing for TES Bolometers
- Frequency-division multiplexing for ac-biased TES Bolometers
- Microwave-resonator multiplexing for dc-biased TES Bolometers: microwave SQUIDs, KPUPs, or direct readout with quantum-limited amplifiers
- Microwave-resonator readout of MKIDs
- UBC MCE for TDM
- McGill digital feedback electronics for FDM
- ROACH2 for resonator TES, microwave SQUID, or MKID
- SLAC LCLS boards for resonator TES, microwave SQUID, or MKID
Advantages/disadvantages, comparison of readout options
- Technological maturity
- Fabrication complexity, yield, uniformity
- Scalability to order [500,000] detectors
Required Work or Studies
- What is technological readiness?
- What are the technical tradeoffs?
- What are unknowns?
- What is timeline for development?
Slides for Discussion
MUX overview: [[Media:Irwin.ReadoutStatusOverview.pdf]]
Time division SQUID multiplexing (Hannes Hubmayr): Media:Hubmayr_cmbs4_tdm.pdf
Adrian Lee: FDM [[Media:2015.09.22.Adrian.Lee.FDM.small.pdf]]
Microwave SQUID multiplexing (Hannes Hubmayr): Media:Hubmayr_cmbs4_umux.pdf
Ed Wollack: Superconducting bump-bond hybridization [[Media:CMBS42014Wollack_Superconducting_Interconnects.pdf]]
Peter Day: KPUPs [[Media:Day_-_KPUP_-_0815.pdf]]
two things in the field TDM FDM
MKID, microwave SQUID, KPUP, Direct TES readout
direct TES variable Q
microwave SQUID and MKIDs
O($100)/pixel is too much O($10) is about right O($1) is too little
table with power dissipation/pixel, physical size,
number of wires to 4K or 300K
MCB, 10 person years of firmware.
cost of producing cold electronics, resonator arrays
how much energy goes into microwave techniques.
we could do both and muddle along
300:1 MUX factor common bias for each detector. constrains fabrication. a lot of cold interconnect
so far not on the wafer. well developed warm electronics. cost per pixel ~$100.
33 channel MUX
LCLS multi slow ATCA crate, kintex
when do we have to decide?
kinetic inductance is modulated by current.
are people going to 300 MHz range...?
practical things - biasing etc.
when do we have to decide?
a few mW, could get 200 to 300 microW
hands on the options in the next year.
What do we do need to demo any detector/combo?
for some things may require a CMB test.
table of parameters action plan to TRL to sell to DOE
if you have a problem with yield, then individual bias good.
magnetic fields and RF sensitivity.
low frequency performance.... understanding of challenges and risk
need 100 mHz 1/f performance since we don't know if we will use modulators.
Kent's cost analysis
O($100)/pixel is too much
O($10) is about right
O($1) is too little
Three categories of MUX
1) TDM and FDM - Mature today for Stage III
Can these be the CMB-S4 readout technology with evolutionary changes?
TDM - hybridization
FDM - hybridization or direct integration
Costs of both are order $100/pixel, so too high at present.
Excellent scalability, and plausible to reach cost.
- Need to demonstrate in experiment(s)*
Great progress on performance
1/f knee at 100 mHz required
3) Microwave Readout of TESes - MSQUIDs, KPUP, Direct coupling to resonator
MSQUIDs on telescope (MUSTANG)
KPUP in lab demo
Direct Coupling at idea stage, requires new amplifier.