NCNR Sample Environment Projects

Yegor Vekhov
Weekly meetings with NCNR team (SE, RFO, ROE, OFPM, AMD, Safety, etc.) (Fall 2019 – Present)

Preparation and submission of procurement paperwork (Fall 2019 – Summer 2020)

Bids evaluation, choosing the Contractor (September 2020)

Bi-weekly meetings with the Contractor on system design, etc. (Fall 2020 – Present)

Helium Recovery System - is a system to collect, store, purify, liquify and re-use 

Helium gas boil-off from wet cryostats / magnets, Helium pumps and transport Dewars
End-User Station (EUS) - 29 pcs and Helium Monitor Station (HMS) - 8 pcs

 Working with the Contractor on EUS and HMS conceptual designs – finished in April 2021

 Designing interfaces between SE equipment (cryostats, He dewars, pumps) and EUS 

 Testing EUS and HMS prototypes - August 2021

 Working with NCNR staff to determine EUS locations at neutron instruments (G100: April –

May 2021; C100 – June 2021). EUS locations are approved by Team Leaders.

 After EUS prototype test is performed, measure and order all hoses/connectors between SE 

equipment (cryostats, He dewars, pumps) and EUS – next FY

Preliminary EUS test results:

- unit arrived to NCNR is malfunction; the contractor will come to fix it at NCNR 
 All cryostats now have wide range pressure transducer 

on Helium pumping line, makes Needle Valve adjustment 

more convenient and robust

MicroPirani MKS910

 All cryostats now have LN2 level sensors

 Most cryostats now have new cryogen level meter,

Allows to measure both levels: LHe and LN2 and to refill automatically 

Model 1700

 All cryostats and their carts have been certified for crane lifting according to new NCNR safety policy

 All operational cryostats have undergone thorough maintenance (thanks Sergiy Gladchenko for his help):

 Needle valve cleaning and re-sealing

 Vacuum jacket valve cleaning

 Cold tests, etc.

 User and Tech manuals for ILL cryostats have been updated (thanks Tanya Dax for editorial assistance)

Maintenance

Developments

Safety
 100mm MACS ILL #4 cryostat: new needle valve has been ordered, installed, tested - Completed

 3He MACS ILL cryostat #14: needle valve refurbishment has been ordered – In progress

 Upgrade of ILL cryostat #13 to three heat exchangers: more cooling power, faster prep and sample change times. 

Commissioned - Completed
 Upgrade of ILL cryostat #13 to three heat exchangers: more cooling power, faster prep and sample change times. 

7/21/2021 1:31:58 PM

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 Cryostat

 Sample (X72787) Temperature (K)

Time

072121 - ILL #13; Three heat exchangers

9:43am

Pumping pressure = 100 torr

1 heat exchanger 

(standard)

3 heat exchangers 

(upgraded)

4-5 hours 90 min

Cryostat performance before and after upgrade

Cooling from 300K to 2K

If funding approved, more cryostats would 

need this type of upgrade
 Collecting the requirements from NCNR scientists

 Market research

 Talking to other neutron facilities 

 Talking to manufacturers and engineering companies

 Preparing procurement paperwork

 Submission to AMD: June 2021

 Award: September 2021

The rotation system consist of 

• Computer controlled rotation stage to be mounted on top flange of the 100mm ILL cryostat

• Rotatable sample stick to be inserted in 100mm sample well

• Interface mounting flange adapter between rotation stage and cryostat flange

• Interface mounting flange adapter between rotation stage and rotatable sample stick

• Controller, cables, software

Funded by NSF
CCR5 – Has an issue with base temp while running in horizontal position. It drifts up after reaching normal 6K 

base temp. What was done: cold head got changed and CCR tested in vertical position. No positive outcome. 

Needs further attention

CCR19 – sensor upgrade, cold test. Works fine.

CANDOR CCR – leak checks
Maintenance/repair:

 Two leak detectors at user stations 

 CCR compressor • Sent out • Received

• Commissioned 
 Binary Gas Analyzer 

Fully integrated into dil fridge gas handling system, this 

diagnostics and troubleshooting tool allows in situ 3He4He mixture analysis.

Suggestion: implement this approach to all NCNR dil

fridges
 User and tech manuals updated. 

Thanks to Tanya Dax for editorial assistance

Thanks to Jonathan Gaudet for the help with manuals tests (cross-training opportunity)

 New sample holder for SANS dil fridge experiments

Collaboration with Jonathan Gaudet • Design

• Thermal conductivity test • Neutron background test
 Market research: Oak Ridge, ISIS UK, HZB – thanks Sergiy Gladchenko for help

 ISIS UK is sharing all the details on their system (drawings, diagrams, BOM)

 Oak Ridge has sent their system to test (drawings, diagrams, BOM)

 HZB: general consultations

Next: • Test Oak Ridge system

• Develop the NCNR system based on the market research
New CANDOR CCR cart (liftable)

• Designed – Jan - Feb 2021

• Hazard Review approved – March 2021

• All parts ordered – April 2021

• Cart assembled – June - July 2021

• Test – September 2021

Cylon 3T magnet Cart (non-liftable)

• Made in 2018

• New requirements: Needs to be liftable

• Design – Fall 2021

Delayed due to lack of engineering support
Solenoid cryo valve

Cryogen level controller 

Allows to maintain LN2 level within preset limits

Next steps: • Instrument scientists to test the system and return the feedback

• For BT7 and MACS: discuss system setup challenges

• Order parts for several LN2 refill sets (FY 2022) and get system ready during 2023 shutdown 
Several different RuO2 sensors have been studied at dil fridge base temperature within 0 – 10T magnetic field.

Experimental setup: • ICE dil fridge

• 10T dry magnet

Sensors studied:  Lakeshore RX202A – has two chips  Lakeshore RX102A (original and new one)  Scientific Instruments RO-600

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B (T)

 Lakeshore

 Inst.Science

 Lakeshore2

RuO2 sensors

Field calibration: ICE dil fridge in 10T

Results: All studied sensors showed magnetoresistance maximum at around 1.5T

Other resistance sensors to test?
Carbon Fiber sample stick made 

by ICEOxford showed excellent 

performance: much faster 

sample change time than Metal 

sample stick

Next to order: Sample stick for 

100mm MACS ILL Cryostat

Thanks Alan Ye for ordering the stick
• ILL cryostats: 15 experiments

• Dil fridge: 4 experiments
• New sample holders

• New low temperature capabilities

• New automation ideas

• New temperature sensors to study at 50mK in magnetic field
Completed projects: • ILL cryostats: maintenance, improvements, procurements • CCR maintenance

• Two leak detectors maintenance

• CCR compressor maintenance

• ICE dil fridge improvements: in situ 3He-4He mixture measurement system, updated manuals

• New CANDOR CCR liftable cart • New LN2 auto refill system

• Carbon Fiber sample stick for ILL cryostat: cold tests

• User support: dil fridge, ILL cryostats

In progress: • Helium Recovery System

• Custom Rotation System for 100mm ILL cryostat • CCR #5 maintenance

• Needle Valve Automatic Control for ILL cryostats

• New Cylon 3T magnet liftable cart • Ultra-low temperature thermometry (research) • New sample holder for SANS dil fridge experiments