Attachment 1 - NIST Requirements.pdf

NIST Requirements Document –QD circuit cryocooler testbed

Background This acquisition is requested in support of projects in the Atom Scale Device Group/Nanoscale Device Characterization Division’s program to develop measurements and devices in support of solid-state quantum information. Specifically, the quantum dot (QD) test devices must be measured with low noise in the small voltage and small current regime. Achieving overall best performance requires development of proximal circuits with samples and printed circuit boards (PCB) integrated together. Ultimately these sample/circuit units will be put into dilution refrigerator (DR) measurement systems, but a faster turnaround system that closely mimics the measurement environment is needed for test and development prior to commitment to the DR.

Scope

QD circuit cryocooler testbed cryostat – A closed-cycle measurement cryostat capable of printed circuit boards with passive and active circuits and custom samples to <4.0 K with a cooling power at least 400 mW at 4.2 K. The cryostat shall have (24) low frequency measurement lines (twisted pair), (9) power supply and control lines, and (8) high frequency lines with SMA connectors. A large sample/PCB space is required as well as interchangeable capability to achieve direct optical access by replacing blank access ports on vacuum can and heat shields with windows (thermal requirements apply to condition when ports are closed with blanks and system is as delivered without a sample). System will also have extra access ports in the vacuum can (e.g., KF40) and aligned ports in the shield(s) for future addition of fiber optics, additional instrumentation, etc. System will have thermometry at each principal stage + a sensor for mounting on the sample/PCB assembly, sample heater and power supply, and a feedback proportional-integral (PI) temperature control system. Sample stage will be provided with a gridded tapped hole pattern for attachment of custom mounting solutions provided by customer.

Minimum Requirements

Overview

A complete, closed cycle cryocooler system that provides self-contained cooling to <4 K, compressor, high pressure He hoses, motor head and instrumentation wiring sets, installed or as kit, including PID temp controller with multichannel monitoring + 2 sensors (e.g, SiOx diode) is sought.

Technical Specifications:

General:

• 120/240 VAC 60 Hz US standard power required for operation

• Compressor shall be water cooled

• Commercial software compatible with Windows 10 shall be provided for temperature controller and any other components with digital control/monitor capability

• Hardware system shall connect to a standard Windows PC via Ethernet or USB connectivity with seamless interface to vendor software for components with digital control

• Base temperature (no load) <4.0K with >400 mW of cooling power at 4.2 K as delivered without additional load due to sample, etc.

• Lower temperature and larger cooling power will be considered as value added

• Sample stage shall reach within 0.1 K of base temperature in <3 hours, faster will be considered added value

• A mechanical support system shall be provided such that the system can be assembled either on the floor or a table top (28 – 36 inches from floor)

• If the system is configured “cold head down” (with motor and feedthroughs above sample cold stage) then at least 6” additional space must be available in all directions in addition to the minimum needed to remove vacuum can, heat shield and any other removable part

• Additionally, the mechanical supports must leave at least two feet in all lateral directions from the sample volume open to enable user mounting a configuration or samples

• If vacuum can or heat shield weight exceeds 30 lbs, vendor shall provide a procedure or mechanical assistance such that a single user can safely operate the system

• Silicon diode sensors or similar will be provided at each temperature stage plus a sensor for attachment on customer sample package

• Heater cartridge capable of applying >1 W of power at 4K is required

• Temperature monitor and controller with P/I feedback required to monitor all sensors and provide open or closed loop power to heater for temperature control

• Active feedback temperature stabilization be <0.1 K for a control temperature not more than

10% greater than base temperature

Instrumentation:

• (48) net low frequency (LF) measurement lines configured in (2) bundles of 24 consisting of 12 twisted pairs with one signal line and one reference line per twisted pair

• LF bundles will have a Fisher connector to the exterior of the cryostat

• The cold plate (<4 K instrumentation stage) will be connectorized with a Micro-D 25 bulkhead connector, mechanically and thermally anchored to the cold plate

• Each LF line will have <30 Ohms resistance from the room temperature connection to the cold plate connection

• Detailed pinout requirement will be provided during design, or upon request if needed by offeror

• (8) SMA connectorized RF/microwave lines shall be provided with SMA bulkhead feedthroughs to the exterior of the cryostat with female SMA connectors and also at the cold plate with female SMA connectors

• Cryostat SMA wiring shall be type UT47 or UT85 stainless steel or similar in a 50 Ohm impedance configuration

• Bulkhead feedthroughs for SMAs on the exterior and the cold plate shall provided at least 1” center to center space between SMA connectors for ease of connection

• A separate power supply (PS) and/or digital control instrumentation bundle shall be provided that is kept spatially and electrically isolated from instrumentation lines with 9 wires

• PS wiring shall have less than 3 dB of loss for frequencies <100 kHz

• PS bundle shall have a C or Dsub type connector at the exterior of the cryostat and a bulkhead style connector at the cold plate of the same type but opposite gender

• Thermometry and sample heater and connectors and wiring are separate from above listed instrumentation lines, but may be combined in the same bundle and connector with power supply/digital lines at vendor’s discretion

Sample space, heat shield, vacuum can and cold plate specs

• A dedicated vacuum pump out port with shutoff valve flanged with KF16, KF25 or KF40 (or equivalent) shall be included

• In addition to ports/feedthroughs provided for the required instrumentation, thermometry and pump out, at least (2) additional ports of KF40/equivalent or larger shall be provided for future use and communicate to free space and passthrough on all stages for future wiring/etc to the cold plate

• Blanks for unused holes on the cold stages shall be included

• A “large” sample cold plate and adjacent space inside the innermost heat shield is required, specifically, at least 10 inch diameter cylinder (or 10 in x 10 in if rectangular) plate and at least 12 inches in the on axis direction

• The cold plate shall be equipped with a grid of tapped holes (1/4-20 or #10-32) with no more than 1” center to center spacing in any area not equipped with instrumentation or blank feedthroughs

• The cold plate shall be mechanically robust, at least ¼” in thickness and supported such that at least 10 kg of mass could be attached

• A heat shield enclosing the sample volume shall be provided and anchored to the first cooling stage, this shield shall have ports with removable blanks aligned with ports (> 1 cm^2) in the vacuum can for future optical access

Reporting Requirements and Deliverables

Government-Furnished Access and Information

Period of Performance and

Place of Performance

Hours of Operation

Crumpler, Forest T. (Fed) Delivery/shipping, installation? Documentation required?

Inspection and Acceptance

Vendor will need to provide factory test data showing temperature vs time illustrating base temperature and cool down time as well as demonstrating cooling power by applying heat to the stage and providing data of steady state temperature for applied powers in increments of not greater than 100 mW spanning [0,1W].

Verification of no visible damage and system reaches within 0.1 of factory base temperature in a time not more than 10% greater than factory test with no load required for final acceptance.