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GTSnext
About GTSnext
Website of collaboration
EU proposal GTSnext http://www.earthtime-eu.eu/OpenDocuments/GTSnext.pdf
http://www.gtsnext.eu/index.php?contentid=3
People involved
Vrije Universiteit Amsterdam – project staff
Ing. Onno Postma
Dr. Leah Morgan
Rob Stoevelaar
Dick van Iperen
GTSNext science collaborators
Dr. Jan Wijbrans Vrije Universiteit - Faculty of Earth and Life Sciences
Dr. Klaudia Kuiper Vrije Universiteit - Faculty of Earth and Life Sciences
Dr. Darren Mark Scottish Universities Environmental Research Centre (SUERC)
Dr. Igor Villa University of Bern
scientist in charge Faculty of Earth and Life Sciences
Faculty of Earth and Life Sciences system engineering
mechanical workshop
mechanical workshop
Wim van der Plas electronics department [email protected]
Process scheme
system_map.pdfFile:
Process description
The system will act to store, clean, and quantitatively measure high purity 40Ar. The source gas will be attached to the system via valve 1. By taking a 10mL pipette from here, we will store and clean a smaller quantity of this gas in the getter region (parts #15,16,25). Another 10mL pipette will allow a fraction of that gas into the main reservoir/pipette region, which will have well calibrated volumes and a pressure gauge attached. After measuring the pressure of the gas at ~1 torr, the pressure gauge valve (#22) will be closed, and then two expansions of gas trapped in the pipette will decrease the pressure to workable levels. Then, 2mL pipette shots of acceptable levels for measurement in mass spectrometers will be taken from the reservoir to calibrate the mass spectrometer.
Argon reservoir: set up
Argon reservoir: description
To be written.Relates to preceding reservoir figure
Pressure gauge MKS 690A ; 0 – 1 torr ; part #19
Pressure gauge MKS type 690A01TRA manual
High accuracy MKS pressure gauges general information 600hi_ac-1_MKS.pdf
Relative error of MKS 690A pressure gauge
MKS_690_manual.pdf
Full scale: 1 torrOutput voltage : 0-10 VoltsTemperature regulated at 45 °CWarm up time before adjusting zero: 4 hours minimumTransducer must be powered continuously.Highest pressure for proper zero adjust: 10-6 torrMaterials exposed to gasses: Inconel, stainless steel
0.01
0.10
1.00
10.00
100.00
1.E-0
5
1.E-0
4
1.E-0
3
1.E-0
2
1.E-0
1
1.E+0
0
Pressure [torr]
Rel
ativ
e er
ror
Accuracy of reading : 0.05 %Resolution 10-5 of full scale 1 torr
Temperature coefficients
Zero: 4×10-6 of full scale/°CSpan: 20×10-6 of span/°C
The unit must be mounted horizontally.
Some specifications
A note about high accuracy capacitive pressure gauges high accuracy Baratrons.pdf
AD converter
Accuracy full : 0.05% × 10 V = 0.5 mV16 bit AD converter: 10 V / 216-1 = 0.3 mV
Swagelok 4BG valves + VCR connectors: parts # 9,10,22
4BG valves documentation 4bg_Swagelok.pdf
VCR documentation VCR_Swagelok.pdf
Pipette construction using 4BG valves parts #9,10
Valve type specification: SS-4BG-VCRVD-5C
Valve body: male VCR connectors, solid body (no Argon welds), 316SS/A479
Vacuum stem tip adaptor: copper with vented slot
Stem + bellow + weld ring: 316 SS/A479, 2 Argon welds between bottom and top plates
Gasket: Silver-plated 316 SS/A580
Volume of valve between valve ends and stem tip: 0.5 mL
VCR components
316L VAR stainless steel SEMI F20‑0305 High-Purity
VAT manual valves, parts # 7,8,11
Valve volume Reihe 57 Volumenberechnung.pdf
VAT manual valves series 57
-DN16 mm -Conflat seals-Valve body, mechanism AISI 304L (1.4306), AISI 316L (1.4435)-Bellows AISI 316L (1.4404)-Cycles until first service 10 000-Heating and cooling rate ≤ 60°C h-1
-Leak rate: body, valve seat < 1 · 10-10 mbar Is-1
-Seal: bonnet, plate metal-Valve body ≤ 450°C open / ≤ 350°C closed-Manual actuator (hex-head) DN 16 ≤ 450°C
-More info in VAT catalogue: Catalog2012_VAT.pdf
Cut through of VAT manual valve
Components: steel general information
General information on steel quality
From scrap metal to vacuum components
…., how is metal processed to give the characteristics required for vacuum processes?...
Design considerations in the use of stainless steel forvacuum and cryogenic equipment.
…..The properties making austenitic stainless steel a preferred material for the construction of high vacuum equipment are reviewed. ….
Outgassing of vacuum materials
…. it presents outgassing rates for various materials in tabulated form……
steel_ESR_CERN.pdf
outgassing.pdf
scrapmetal.PDF
Insert: part #18
The insert is made of 316LN vacuum fired stainless steel and has a well known volume, approximately 200 mL
Visit Nederlands Meet Instituut- NMI 20 april 2010
Onno and Leah visited NMI in DelftContact person: mr. van Veghel
Cylinder
The slug design was presentedThe design appeared to be measurable by NMIAchieved accuracy in measuring is < 1 m
Diameter will be measured at several points along the length axis of the cylinderThe diameter form error of the cylinder diameter will be measured along the full length of the cylinder
The round offs at the cylinder ends of R=0.5 mm can be measured.NMI however has to find an appropriate measuring procedure but they are optimistic.
The parallelism of the end faces will be measured with the stated accuracy of < 1 m.The form error of the end faces will be measured .
NMI will assist us in calculating the confidence interval for the slug total volume
The indicated surface roughness of 0.025 m is sufficient with respect to the accuracy we want to achieve.
Sphere
We also discussed the possibility of using multiple spheres instead of a cylinder. He was very positive about using spheres especially because the form error of the sphere (roundness or sphericity) is easier to measure with the high accuracy we intend to achieve. Spheres are produced in mass quantities at precision grades and are therefore much cheaper than a specialty cylinder.
Argon source gas
Composition of Argon test gas
Source of Argon test gas : Oak Ridge National Laboratory
Lee_atmAr.GCA.2006.pdfFull description of Oak Ridge Argon test gas preparation and properties
Bottle with CF16 flange (scale in inches)
