# Presentation: 407873

## TXR Interface Requirements

- Joe Rice
- National Institute of Standards and Technology
- Gaithersburg, MD

## Slide 2

## Summary of TXR Chamber Interface Requirements

- Mechanical/Optical
- Mount TXR cryostat horizontally within chamber so that source under test overfills TXR pupil without obstruction.
- (optional/TBD) Shroud TXR within flight-instrument-like housing to better simulate radiometric environment.
- Cryogenic
- Two (2) nitrogen lines connecting to TXR cryostat:
- 1 for filling TXR LN2; 1 for venting LN2/GN2.
- Means for refilling with LN2 at <30 PSI once every 12 hours..
- Electrical
- Cable harness & feedthroughs for 20 shielded, 4-wire cables.
- (shields insulated: 100 insulated pins at feedthrough)
- Space and standard 120 VAC outlets for two electronics racks.
- (optional) Floating BNC feedthrough for LN2 level sensor.

## Mechanical/Optical

- Refer to AutoCAD Drawing for dimensions.
- Currently only Version 1.0 is available.
- Version 2.0 design to be released by end of July 2000.
- Version 2.0 changes to be implemented by end of July 2000.
- Changes consist mainly of addition of foreoptics and filling in some drawing details left out of Version 1.0.
- Version 2.0 anticipated parameters:
-  TXR cryostat will fit into a box that measures:
-  47 cm tall, 55 cm deep along optical axis, 35 cm wide
- (18.5” x 22” x 13.5”)
- TXR cryostat weight <80 lbs.
- Optical axis is centered on width, 2.375” above bottom of baseplate.
- Entrance pupil located 10.9” behind front edge of baseplate.
- Aperture stop diameter <2 cm, full field of view <2° circular.
- Flat scene plate painted with Z306 diffuse black paint will be available for mounting onto front of baseplate.

## Mechanical/Optical (continued)

- TXR cryostat should be mounted horizontally from bottom of baseplate using bolts through the 4 clearance holes (0.265” diameter) provided on the baseplate at 10” spacing.
- If electrical connections are in place, TXR internal red visible laser diode can be used for coarse alignment of optical axis.

## TXR Anticipated Version 2 Changes

- Units: Inches

## Using Checksource

- Using
- Turning Mirror

## Cryogenic

- TXR cryostat fill and vent ports terminate in horizontally-oriented 1/2” Cajon VCR fittings.  The rotatable female nut is on the TXR side of these fittings.  Two flexible SS tubes to the TXR that terminate in male 1/2” Cajon VCR fittings are required.
- An electronic level control unit ships with the TXR:
- A vacuum-compatible solenoid valve is available for mounting at the TXR cryostat fill port if needed.
- An air-side solenoid valve for mounting to the TXR fill tube is available if needed.  This is preferred over the vacuum-side valve.
- Host facility supplies pressurized LN2 & means of exhausting GN2.
- LN2 source pressure must be less than 30 PSI.  25 PSI works.
- TXR cryostat LN2 dewar has 4.5 liter capacity.
- LN2 usage estimate: <40 liters for initial cooldown, < 15 liters each day thereafter, with refills required every 12 hours.
- (Optional) GN2 for purging cryolines for quick warmup at end.

## Vacuum and Contamination Control

- TXR is compatible with a 10-6 Torr vacuum levels.
- Materials used are consistent with <1% TML, <0.1% VCM.
- Planning to have TXR cryostat tested and for outgassing levels at NIST using TQCM’s and CQCM’s.
- Internal TXR cryostat vacuum is to be re-pumped at host facility prior to cooling using turbo-pump that ships with TXR.
- Vacuum valve on top of cryostat is closed after re-pumping, just before final chamber closure/pumpdown operations, to separate TXR internal vacuum from host chamber vacuum.
- Planning to procure a QCM for TXR external surface monitoring.
- TXR cryostat was kept in a Class 100 cleanhood during assembly.
- It is kept in a Class 10,000 cleanroom when possible, but normally the TXR must be used in ordinary laboratory conditions as well.
- Alcohol wipedown of cryostat surfaces prior to chamber interface is recommended: suggest that this be done by NIST personnel.

## Electrical

- Cable harness & feedthroughs for 20 shielded, 4-wire cables.
- Each cable has 4, AWG24 insulated wires with a common shield.
- Each shield should be carried through connectors on separate pins.
- Shields should be floating above ground and insulated from each other throughout.  Single-point grounding of shields is already done on TXR side of connectors.
- Air-side cable harness should terminate at two (2) standard density 50-pin _male_ D connectors, labeled A and B.  This harness must reach to rear of TXR instrument rack.  A and B connector separation >1ft.
- Vacuum-side cable harness should terminate at two (2) standard density 50-pin _female_ D connectors, labeled A and B.  This harness must reach to within 6ft of rear of TXR cryostat position in chamber. (Alternatively: this end could terminate at four (4) standard density 25-pin _male_ D connectors, labeled A, B, C, and D, that reach to rear of TXR cryostat position + 1ft.  Allow for connector separation >1ft.)
- Pinouts follow TXR Interface Manual Version 2.0 wiring chart.

## Slide 11

## Electrical (continued)

- TXR air-side electronics racks: Instrument Rack and Computer Rack
- Each rack requires one (1) 120 VAC, 50/60 Hz outlet.
- Both racks are Hardigg 19” double-entry rack shipping containers on removable castors.  Cable entry is from rear.
- Instrument Rack measures 28”W x 29”D x 50”H and should be as close to chamber as possible to minimize cable lengths.  NIST personnel requires occasional access to this rack.
- Computer Rack measures 29”W x 36”D x 61”H and can be placed at a more convenient location, within IEEE-488 GPIB cable-length limits.  NIST personnel normally will be stationed at this rack.
- Access for IEEE-488 cable and high-level signal cable (cables ship with TXR) must be provided to connect between the two racks.

- (optional) Floating-shell BNC feedthrough for LN2 level sensor.
- Include coaxial cable (RG-59U: 75 ) on vacuum side that reaches at least to center of TXR cryostat position, with male BNC termination.

## Data

- Means for recording, time stamping, and sharing relevant environmental and radiometric data are required.
- For example, setpoint temperature(s) of source(s) under test must be incorporated into TXR data record.
- TXR data are acquired through IEEE488 interface by a PC running software written in National Instruments LabView.
- Data are saved to hard drive automatically and backup up on 100 MB zip disks manually by NIST personnel.
- Archive file is accumulated throughout deployment, typically at few second intervals.
- Reduced files accumulated for specific tests.  Software for reduced files is customized as per test plan.
- All files are tab-delimited text files, with a single header at the beginning that includes date/time stamp and TXR instrument configuration parameters.

## Examples of How TXR Interface Requirements Have Been Met

- Los Alamos Deployment Test: July 1999
- NIST Medium Background Infrared Facility: Ongoing

## TXR at Los Alamos Radiometric Calibration Chamber Facility

## Slide 16

## TXR Cryostat interfacing NIST MBIR chamber