The authors are thankful for the help of the NIST neutron imaging facility instrument scientist Dr. Daniel Hussey for assisting us with neutron radiographs.

1. Procure Non-custom Parts for the Spring Transport Mechanism
<ol>
	<li>Procure the springs, threaded rod, standoffs, nuts, and washers. These items are listed in the List of Specific Materials/Equipment. Purchase the springs and standoffs before manufacturing the ball holder. Use 18-8 stainless steel (except 303), or preferably 316 stainless steel, for all materials.</li>
	<li>Procure rotor. The rotor is a ball-bearing 4.5 mm in diameter made of 440C stainless steel or E52100 alloy steel.</li>
	<li>Procure the right-angle valve listed in the List of Specific Materials/Equipment.</li>
</ol>
2. Procure Materials for the Shipping Container
<ol>
	<li>Procure the shipping container. Use rotationally-molded, polyethylene hard-shell cases with protected recesses since these were the type of cases that were successfully tested. The case in the List of Specific Materials/Equipment meets the minimum interior space requirements.</li>
	<li>Procure the foam packing.
	<ol>
		<li>Procure 2# (32 kg/m3) polyurethane (ester) foam. Purchase enough ester foam to fill the top and bottom of the shipping container. Purchase a piece of 5 cm egg-carton ester foam.</li>
		<li>Procure 2# (PE) polyethylene foam that is 7.6 cm thick and has a large enough area to cover the width and depth of the shipping container.</li>
	</ol>
	</li>
</ol>
3. Procurement and Fabrication of Custom Parts for the Spring-transport Mechanism&#160;
Note: Example drawings of the custom parts described in this section are given in Figures 2-4.&#160;
<ol>
	<li>Produce and submit drawings to custom vendor or in-house shop for manufacturing the spinning rotor gauge (SRG) thimble/flange. Critical dimensions are given in Figure 2. The custom manufacturer must be familiar with ultra-high vacuum (UHV) manufacturing techniques. The thimble is relatively simple to manufacture and is well within the ability of many vacuum component companies.</li>
	<li>Acquire the tines that hold the SRG head to the flange (see Figure 1). These may be removed from the commercial SRG thimble/flange assembly that comes with the SRG electronic control unit. Each tine is held in place by a single bolt (typically a metric hex socket head) with a lock washer, and may be removed by unbolting using the appropriate wrench (such as a metric hex key).
	<ol>
		<li>Alternatively, fabricate these by the same vendor providing the thimble/flange as in the previous step, but ultra-high vacuum manufacturing techniques need not be followed. Make exact copies of the commercial SRG tines.</li>
	</ol>
	</li>
	<li>Produce and submit drawings for the simple adapter to connect the M6 stud on the right-angle valve to an 8-32 all-thread stud (American standard hardware). See Figure 3.</li>
	<li>Produce and submit drawings for the fabrication of the ball holder. Critical dimensions are given in Figure 4. Fabricate the ball holder of 316L stainless steel in accordance with UHV manufacturing techniques. Tack weld the ball holder to one end of a spring. Tack weld the other end of the spring to the standoff. Clean all parts in accordance to the cleaning procedure given in section 5.</li>
	<li>Cut the 8-32 all-thread stud to a length of 18 mm and clean as described in section 5.</li>
</ol>
4. Fabrication of Custom Foam Cut-out
<ol>
	<li>Make a cut-out for the spring-transport mechanism in the PE foam. Follow the contours of the valve assembly as closely as possible. Do this by hand using a sharp utility knife; alternatively, the contour may be professionally cut by a packaging supplier.</li>
	<li>Use the dimensions of the valve given by the valve manufacturer and the thimble/flange dimensions given in Figure 2. Cut the space for the thimble large enough to accommodate the tines (1.5 cm x 3.8 cm).</li>
</ol>
5. Cleaning of the Vacuum Components&#160;
<ol>
	<li>Clean all vacuum components for ultra-high vacuum (UHV) before assembly. Our recommended cleaning procedure is as follows.
	<ol>
		<li>Handle vacuum parts using Nitrile, Latex, or vinyl gloves. Do not touch with bare hands.</li>
		<li>Clean parts using a mild detergent (such as listed in the materials/equipment list) dissolved in distilled or de-ionized water and a lint-free cloth.</li>
		<li>Place parts in a bath of mild detergent dissolved in distilled or de-ionized water and place in an ultra-sonic cleaner for 20 min.</li>
		<li>Rinse parts thoroughly with distilled or de-ionized water.</li>
		<li>Cover parts with acetone and place in an ultra-sonic cleaner for 20 min.</li>
		<li>Remove parts from acetone. Cover parts with ethanol and place in an ultra-sonic cleaner for 20 min.</li>
		<li>Remove parts from ethanol. Rinse thoroughly with distilled or de-ionized water.</li>
		<li>Blow the parts dry with dry nitrogen or clean dry air.</li>
		<li>Let parts air dry on a clean-room quality lint-free cloth for 24 hr.</li>
	</ol>
	</li>
</ol>
6. Assemble the Spring-transport Mechanism
<ol>
	<li>During assembly, wear nitrile, vinyl, or latex gloves. Do not touch vacuum parts with bare hands.</li>
	<li>Gather the necessary tools: needle nose pliers, socket head driver for 8-32 nut, wrench for adapter, ruler or caliper. Wipe clean the ruler/micrometer with ethanol; clean all other tools using the procedure in step 5.</li>
	<li>Gather the necessary parts: the valve, thimble, ball-bearing, ball-holder/spring assembly (see step 3.5), 18 mm long 8-32 stud, thread adapter, nuts, and lock-washers, 3 mm Allen wrench and masking tape. See Figure 5.</li>
	<li>Spring-Transport Mechanism Assembly:
	<ol>
		<li>Fully close the right-angle valve by turning it clockwise until it stops.</li>
		<li>Looking through the valve ports, identify the M6 stud centered on the valve seat.</li>
		<li>Screw the adapter snugly onto the M6 stud. Insert an UHV clean wrench or pliers through the port to get the adapter as snug as possible.</li>
		<li>Insert 8-32 stud into the other end of the adapter. Tighten as snugly as possible. The 8-32 stud will extend through the adapter and push against the M6 stud.</li>
		<li>Place lock-washer on 8-32 stud and then a nut. Tighten the nut using a clean socket driver or pliers. The valve may be closed during this step to make tightening easier.</li>
		<li>Place a nut on the 8-32 stud. Turn it until nearly touching the nut on the other end. Place lock washer on 8-32 stud.</li>
		<li>Attach spring/ball-holder to the 8-32 stud by the standoff. Turn the standoff until it is touching the lock-washer. 
		Note: The following procedure describes how to check the length adjustment of the spring assembly, see Figure 6.</li>
		<li>Place the rotor in the custom thimble and secure it with a magnet (from a commercial SRG) by placing it on the thimble end and fixing it with masking tape. The rotor is now at the end of the thimble.</li>
		<li>Slide thimble over spring/ball-holder, stop when the ball-holder touches the ball. Measure the gap between the valve flange and thimble flange, as in Figure 6.
		<ol>
			<li>If the gap is in the range of 2 mm to 6 mm, skip to step 6.4.10.2). A nominal gap of 3 mm is ideal, but a gap in the range is of 2 to 6 mm sufficient. A gap smaller than 2 mm is not acceptable.</li>
			<li>Remove thimble/flange assembly and set aside. If the gap was smaller than 2 mm, rotate the standoff counterclockwise to make the gap larger. If the gap was larger than 6 mm, rotate the standoff clockwise to make the gap smaller. Go back to step 6.4.10.</li>
		</ol>
		</li>
		<li>Remove thimble/flange assembly and set aside. If the gap was smaller than 2 mm, rotate the standoff counterclockwise to make the gap larger. If the gap was larger than 6 mm, rotate the standoff clockwise to make the gap smaller. Go back to step 6.4.10.</li>
		<li>Tighten the nut against the standoff.</li>
		<li>Open the valve by turning counter-clockwise.</li>
	</ol>
	</li>
	<li>Assemble the Flange:
	<ol>
		<li>Remove rotor by removing masking tape and magnet and carefully allowing the rotor to roll out of the thimble.</li>
		<li>Attach the two tines to the flange using a lock-washer and bolt inserted through the back-side of the custom flange/thimble. The lock-washer and bolt are provided by the commercial SRG. The lock-washer and bolt do not need to be cleaned for ultra-high vacuum.</li>
		<li>Rotate the tines so that they are square with one another, as in Figure 1 and Figure 9.</li>
		<li>Check tines for straightness by slipping the SRG head over the thimble. The head should slide on freely.</li>
		<li>Give the two bolts a final tightening and re-check for alignment as in step 6.5.3.</li>
		<li>Place rotor back into the thimble, and secure with the magnet and masking tape.</li>
	</ol>
	</li>
	<li>Complete Spring Transport Assembly:
	<ol>
		<li>Place copper or silver-plated copper gasket on the valve port.</li>
		<li>Place the rotor into the thimble (if not already in thimble from step 6.5.6).</li>
		<li>Slide the flange/thimble assembly over the spring/ball-holder. Orient the flange such that the set-screw in the tines will be pointing downward when the valve is attached to the chamber.</li>
		<li>Using &#188;-28 bolts and nuts, secure the flange to the valve.</li>
		<li>Close the valve.</li>
		<li>Remove magnet and tape holding the ball.</li>
	</ol>
	</li>
</ol>
7. Assemble the Shipping Container
<ol>
	<li>Cut the ester foam to the size of the shipping container. The thickness of the foam will depend on the height of the container. Place a minimum thickness of 7.6 cm of foam in the bottom. Figure 7 shows the foam assembly.</li>
	<li>Place the PE foam cutout on top of the ester foam.</li>
	<li>Place a layer of ester foam in the lid. The minimum thickness should be 7.6 cm. Figure 8 shows the final placement of the spring-transport mechanism. Use clean aluminum foil and a plastic endcap (that came with the valve) to protect the open end of the valve port during shipment.</li>
</ol>
8. Using the Spring-transport Mechanism
<ol>
	<li>Mounting and suspending the rotor: 
	Note: Figure 9 shows the mounted spring-transport mechanism with the head attached. The first step is remove the spring-transport mechanism from the shipping container. In the following, it is assumed that the reader is familiar with the operation of the spinning-rotor gauge. Details of operating the controller can be found in the controller user manual. It is also assumed the reader is familiar with high-vacuum technology.
	<ol>
		<li>Remove the endcap and foil from the open port of the spring transport mechanism. Attach the open port to a DN 40 (CF 2.75&#34;) port on a vacuum chamber using a new copper or silver-plated copper gasket and a &#188;-28 bolt set. The orientation of the valve will depend on the orientation of the tines. The proper orientation is shown in Figure 9. The tine with the set screw points downward. Slip the head over the thimble, the orientation of the thimble should be vertical to within 2&#176;.&#160; Check orientation with a level.</li>
		<li>Evacuate the vacuum chamber to less than 10-3 Pa. Slowly open the spring-transport mechanism valve.</li>
		<li>Attach head to the controller. Turn on controller and suspend the ball.</li>
	</ol>
	</li>
	<li>De-mounting the Spring-Transport Mechanism
	<ol>
		<li>De-suspend the rotor using the electronic controller. Turn off controller.</li>
		<li>Close the spring-transport mechanism valve.</li>
		<li>Remove head.</li>
		<li>Vent vacuum chamber.</li>
		<li>Remove the spring-transport mechanism by un-bolting the valve port from the vacuum chamber.</li>
		<li>Place clean foil and a plastic endcap over the open port of the spring-transport mechanism. Place spring-transport mechanism in cut-out in shipping container.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Fremerey, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+spinning+rotor+gauge.">The spinning rotor gauge.</a> J. Vac. Sci. Technol. A. 3 (3), 1715-1720 (1985).</li><li>Jousten, K., Jousten, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+13,+Total+Pressure+Vacuum+Gauges.">Chapter 13, Total Pressure Vacuum Gauges.</a> Handbook of Vacuum Technology. , 573-583 (2008).</li><li>Berg, R. F., Fedchak, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NIST+Calibration+Services+for+Spinning+Rotor+Gauge+Calibrations.">NIST Calibration Services for Spinning Rotor Gauge Calibrations.</a> NIST Special Publication. , 250-293 (2015).</li><li>Messer, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intercomparison+of+Nine+National+High-vacuum+Standards+under+the+Auspices+of+the+Bureau+International+des+Poids+et+Mesures.">Intercomparison of Nine National High-vacuum Standards under the Auspices of the Bureau International des Poids et Mesures.</a> Metrologia. 26, 183-195 (1989).</li><li>Jousten, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Results+of+the+regional+key+comparison+Euromet.M.P-K1.b+in+the+pressure+range+from+3+x+10-4+Pa+to+0.9+Pa.">Results of the regional key comparison Euromet.M.P-K1.b in the pressure range from 3 x 10-4 Pa to 0.9 Pa.</a> Metrologia. 42 (1A), 07001 (2005).</li><li>Jousten, K., Santander Romero, L. A., Torres Guzman, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Results+of+the+key+comparison+SIM-Euromet.M.P-BK3+(bilateral+comparison)+in+the+pressure+range+from+3+x+10-4+Pa+to+0.9+Pa.">Results of the key comparison SIM-Euromet.M.P-BK3 (bilateral comparison) in the pressure range from 3 x 10-4 Pa to 0.9 Pa.</a> Metrologia. 42 (1A), 07002 (2005).</li><li>Yoshida, H., Arai, K., Akimichi, H., Hong, S. S., Song, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Final+report+on+key+comparison+APMP.M.P-K3:+Absolute+pressure+measurements+in+gas+from+3+x+10-6+Pa+to+9+x+10-4+Pa.">Final report on key comparison APMP.M.P-K3: Absolute pressure measurements in gas from 3 x 10-6 Pa to 9 x 10-4 Pa.</a> Metrologia. 48 (1A), 07013 (2011).</li><li>Fedchak, J. A., Bock, T. h., Jousten, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bilateral+key+comparison+CCM.P-K3.1+for+absolute+pressure+measurements+from+3+x+10-6+Pa+to+9+x+10-4+Pa.">Bilateral key comparison CCM.P-K3.1 for absolute pressure measurements from 3 x 10-6 Pa to 9 x 10-4 Pa.</a> Metrologia. 51 (1A), 07005 (2014).</li><li>Fedchak, J. A., Arai, K., Jousten, K., Setina, J., Yoshida, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recommended+practices+for+the+use+of+spinning+rotor+gauges+in+inter-laboratory+comparisons.">Recommended practices for the use of spinning rotor gauges in inter-laboratory comparisons.</a> Measurement. 66, 176-183 (2015).</li><li>Rohl, P., Jitschin, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+of+the+spinning+rotor+gauge+with+a+novel+transport+device+as+a+transfer+standard+for+high+vacuum.">Performance of the spinning rotor gauge with a novel transport device as a transfer standard for high vacuum.</a> Vacuum. 38 (7), 507-509 (1988).</li><li>Fedchak, J. A., Scherschligt, J., Sefa, M., Phandinh, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Building+a+spring-transport+package+for+spinning+rotor+gauges.">Building a spring-transport package for spinning rotor gauges.</a> J. Vac. Sci. Technol. A. 33 (3), (2015).</li><li>Hussey, D. S., Jacobson, D. L., Arif, M., Coakley, K. J., Vecchia, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Situ+Fuel+Cell+Water+Metrology+at+the+NIST+Neutron+Imaging+Facility.">In Situ Fuel Cell Water Metrology at the NIST Neutron Imaging Facility.</a> J. Fuel Cell Sci. Technol. 7 (2), 021024 (2010).</li><li>Chang, R. F., Abbott, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+affecting+the+reproducibility+of+the+accommodation+coefficient+of+the+spinning+rotor+gauge.">Factors affecting the reproducibility of the accommodation coefficient of the spinning rotor gauge.</a> J. Vac. Sci. Technol. A. 25 (6), 1567-1576 (2007).</li></ol>

Commercial equipment is identified in this paper to foster understanding and does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it necessarily imply that the materials or equipment identified are necessarily the best available for the purpose. The authors have nothing else to disclose.

The objective was to design a spring-transport mechanism with a sufficient holding force such that the rotor would remain immobilized during transport. Designing a robust spring-transport mechanism is not enough to insure the rotor will remain immobilized because, for example, dropping the mechanism from tall height onto a hard surface can produce an enormous shock. The force on the rotor can be greatly reduced by packaging the spring-transport mechanism such that it gently decelerates over a distance within the package,...

The spinning rotor gauge (SRG) is a high-vacuum gauge used to determine vacuum pressures in the range of 1.0 x 10-4 Pa to 1.0 Pa. It is fundamentally a rotating steel ball that is suspended between two permanent magnets. Electro-magnets are used to rotate, or &#34;spin-up&#34;, the ball to some frequency (typically 410 Hz); the ball is then allowed to freely rotate, but the rotation rate will decrease over time because of collisions of gas molecules in the vacuum system with the ball surface. Vacuum pressure is thus related to the deceleration rate of the steel ball or rotor. Figure 1 shows the essential elements of the SRG: the rotor, thimble, head with connecting cable, and electronic controller. The rotor, or ball, is contained within the thimble during operation and is normally not handled by nor is visible to the SRG user. The thimble is connected to the vacuum system. To operate the SRG, the head is slipped over the thimble. The head contains two permanent magnets and several sets of wire coils used for vertical and horizontal stabilization, driving the rotor, and sensing the rotation. The electronic controller interprets the signal from the sensing coil so that a pressure measurement can be made. For a rotor with ideal surface conditions, the deceleration rate is related to the vacuum pressure by fundamental physics. To make absolute pressure measurements using an SRG, a calibration factor, known as the effective accommodation coefficient, must be determined. The effective accommodation coefficient depends on the real surface conditions of the rotor, such as the roughness, adsorbed gases, and scratches. These factors tends to be stable over the course of its use. Additional details of SRGs can be found in other references.1-3
The SRG is used in applications where absolute vacuum measurements are required. For example, calibration laboratories often use SRGs as an absolute vacuum standard. In this case, high-vacuum gauges are calibrated by comparing their reading to that of the SRG. In turn, the SRG standard must be periodically calibrated by shipping the SRG to a primary calibration laboratory to have its accommodation coefficient re-determined. Primary calibration labs are usually National Metrology Institutes such as the National Institute of Standards and Technology (NIST). The primary lab determines the SRG accommodation coefficient by comparing its reading to a primary vacuum standard, and then returns the SRG to the &#34;secondary&#34; calibration lab. The SRG is also used as a transfer standard for the comparison of standards between calibration laboratories or National Metrology Institutes. In this application, the SRG is transported domestically or internationally between the various laboratories.4-8 During shipment, events can occur that change the accommodation coefficient. Prior to shipment, the rotor must be de-suspended and the head is removed; the rotor then rests on the interior wall of the thimble. During transport, the rotor surface is subject to change from the mechanical action between the rotor and thimble due to vibrations and shocks, or the surface may change due to the exposure of the rotor to atmospheric gas and humidity. These changes affect the long-term stability of the accommodation coefficient. Ideally, the rotor should remain in vacuum and immobilized during transport.
Historically, SRGs have been used as transfer standards in key comparisons of vacuum standards among national metrology institutes, where SRGs are internationally transported many times among the various institutes.9 During an early key comparison, it was found that the long-term stability of the SRG accommodation coefficient could be improved by utilizing a spring-transport mechanism which both immobilized the rotor and kept it under vacuum during transportation.1,10 Since then, the spring-transport mechanism has been used many times in international key comparisons. A recent study of the historical data showed that 90% of these comparisons had stabilities better than 0.75%, and 70% had stabilities of 0.5%.9 Therefore, using a spring-transport mechanism will, in most cases, yield a stability that is more than sufficient for most applications.
Until now, there has been little guidance in the literature on how to build a spring-transport mechanism. Early versions of these devices have been known to fail to fully immobilize the rotor, due to a combination of being insufficiently designed for robustness, and being mishandled during shipment. These early lessons show that it is important both to build a robust spring-transport mechanism, and to properly package it in a way that minimizes shock during transport. This later point is critical but often ignored. Here we will describe the construction of a robust spring-transport mechanism in addition to a properly constructed transport package. Our design is based on a few simple, tested, engineering principles that enable the construction of a durable spring-transport package that minimizes the possibility of failure during transport. We also describe our tests of the robustness of our design. Additional details of the test methods can be found in Fedchak et al. (2015).11

<table>
	<tbody>
		<tr>
			<td>Spring, 3 N/m</td>
			<td>Lee Spring (www.leespring.com)</td>
			<td>LC 042C 18 S316</td>
			<td>Outside diameter 0.240 in, Wire Diameter 0.042 in, Rate 17.1 lb/in, Free Length 2.25 in, Number of Coils 29.3&#160;&#160;</td>
		</tr>
		<tr>
			<td>8-32 threaded rod, 316 stainless steel</td>
			<td>McMaster-Carr (www.mcmaster.com)</td>
			<td>90575A260</td>
			<td>Type 316 Stainless Steel Fully Threaded Stud 8-32 Thread, 3&#34; Length.&#160; Cut to length specified in protocol</td>
		</tr>
		<tr>
			<td>standoffs, 8-32 Screw Size</td>
			<td>McMaster-Carr (www.mcmaster.com)</td>
			<td>91125A140</td>
			<td>18-8 Stainless Steel Female Threaded Round Standoff, 1/4&#34; OD, 1/4&#34; Length, 8-32 Screw Size</td>
		</tr>
		<tr>
			<td>nuts, 8-32</td>
			<td>McMaster-Carr (www.mcmaster.com)</td>
			<td>90205A309</td>
			<td>316 SS Undersized Machine Screw Hex Nut 8-32 Thread Size, 1/4&#34; Width, 3/32&#34; Height</td>
		</tr>
		<tr>
			<td>Split Lock-Washers, 316 Stainless Steel</td>
			<td>McMaster-Carr (www.mcmaster.com)</td>
			<td>92147A425</td>
			<td>Type 316 Stainless Steel Split Lock Washer NO. 8 Screw Size, .3&#34; OD, .04&#34; min Thick</td>
		</tr>
		<tr>
			<td>Steel Rotor</td>
			<td>McMaster-Carr (www.mcmaster.com)</td>
			<td>9292K38</td>
			<td>&#160;Bearing-Quality E52100 Alloy Steel, Hardened Ball, 4.5 mm Diameter</td>
		</tr>
		<tr>
			<td>Right-Angle Valve</td>
			<td>VAT Valve (www.vatvalve.com)</td>
			<td>54132-GE02-0001</td>
			<td>Easy-close all-metal angle valve, DN 40 (1.5&#34;)</td>
		</tr>
		<tr>
			<td>Shipping Container</td>
			<td>Allcases, Reekstin &#38; Associates (www.allcases.com)</td>
			<td>REAL1616-1205</td>
			<td>Zinc Hardware w/Zinc Handles, Rotationally Molded, light-weight, high-impact, Polyethylene Case with protected recessed hardware.&#160; 15.75&#34; X 15.88&#34; X 16.45&#34;</td>
		</tr>
		<tr>
			<td>Ester Foam</td>
			<td>Carry Cases Plus (www.carrycasesplus.com)</td>
			<td>ES-PAD 3&#34; Thick</td>
			<td>3&#34; Thick, 2lb Charcoal Ester Foam Pad, 24&#34; x 27&#34;.&#160;</td>
		</tr>
		<tr>
			<td>Ester Foam</td>
			<td>Carry Cases Plus (www.carrycasesplus.com)</td>
			<td>ES-PAD 1&#34; Thick</td>
			<td>1&#34; Thick, 2lb Charcoal Ester Foam Pad, 24&#34; x 27&#34;.&#160;</td>
		</tr>
		<tr>
			<td>Egg-carton ester foam</td>
			<td>Carry Cases Plus (www.carrycasesplus.com)</td>
			<td>ES-CONV</td>
			<td>ES-CONV, 2lb, 24&#34; x 27&#34; x 1 1/2&#34;.&#160; &#34;egg-crate&#34; ester foam.&#160;</td>
		</tr>
		<tr>
			<td>Foam Cutout, PE foam</td>
			<td>Willard Packaging Co. (www.willardpackaging.com)</td>
			<td></td>
			<td>Custom Foam Cutout.</td>
		</tr>
		<tr>
			<td>Spinning Rotor Gauge&#160;</td>
			<td>MKS Instruments (www.mks.com)</td>
			<td>SRG-3</td>
			<td>Controller, head, and thimble.&#160; Custom thimble must be used for the spring-transport mechanism</td>
		</tr>
		<tr>
			<td>Custom thimble</td>
			<td>MDC vacuum Inc. (www.mdcvacuum.com)</td>
			<td></td>
			<td>drawing must be submitted for custom part</td>
		</tr>
		<tr>
			<td>Detergent</td>
			<td>Fisher Scientific Co (www.fischersci.com)</td>
			<td>04-320-4</td>
			<td>Sparkleen 1 Detergent</td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Fisher Scientific Co (www.fischersci.com)</td>
			<td>A18-S4</td>
			<td>Acetone (Certified ACS)</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Warner-Graham Company (www.warnergraham.com)</td>
			<td>190 proof USP</td>
			<td>190 Proof USP ethyl alcohol</td>
		</tr>
		<tr>
			<td>Bolt set for valve</td>
			<td>Kurt J. Lesker (www.lesker.com)</td>
			<td>TBS25028125P</td>
			<td>&#160;B,N&#38;W SET,12 POINT,(25)1/4-28X 1.25&#34;FOR 2.75&#34;THRU,SILVER PLAT&#160;</td>
		</tr>
		<tr>
			<td>Silver-plated copper gaskets</td>
			<td>Kurt J. Lesker (www.lesker.com)</td>
			<td>GA-0275LBNSP</td>
			<td></td>
		</tr>
		<tr>
			<td>Spring Assembly (welding)</td>
			<td>Omley Industries, Inc. (www.omley.com)</td>
			<td>N/A</td>
			<td>The machine work and welding were done in NIST&#39;s shop. However, Omley industries was used as an alternative for welding the spring assembly.</td>
		</tr>
	</tbody>
</table>

how to build a vacuum spring-transport package for spinning rotor gauges

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to 1.0 Pa. In this application, the SRGs are frequently transported to laboratories for calibration. Events can occur during transportation that change the rotor surface conditions, thus changing the calibration factor. To assure calibration stability, a spring-transport mechanism is often used to immobilize the rotor and keep it under vacuum during transport. It is also important to transport the spring-transport mechanism using packaging designed to minimize the risk of damage during shipping. In this manuscript, a detailed description is given on how to build a robust spring-transport mechanism and shipping container. Together these form a spring-transport package. The spring-transport package design was tested using drop-tests and the performance was found to be excellent. The present spring-transport mechanism design keeps the rotor immobilized when experiencing shocks of several hundred g (g = 9.8 m/sec2 and is the acceleration due to gravity), while the shipping container assures that the mechanism will not experience shocks greater than about 100 g during common shipping mishaps (as defined by industry standards).

All of the components of commercial SRG are shown in Figure 1. This includes the rotor, thimble, head containing the permanent magnets and wire coils used for suspension and pickup, and the electronic controller. The small spring shown (Figure 1c) is used to retain the ball in the thimble; this retainer spring is not used in the spring-transport mechanism. The commercial controller and head are used in the spring-transport mechanism. The tines from the co...

Watch this Scientific Journal Video about How to Build a Vacuum Spring-transport Package for Spinning Rotor Gauges at JoVE.com

How to Build a Vacuum Spring-transport Package for Spinning Rotor Gauges

Here we describe how to build a robust spring-transport mechanism for a spinning rotor gauge. This device securely immobilizes the rotor and keeps it under vacuum during transportation. We also describe packaging that minimizes the risk of damage during transport. Tests show our design works for typical shocks during transport.

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to ...

how-to-build-vacuum-spring-transport-package-for-spinning-rotor

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9.1K Views.  National Institute of Science and Technology. Here we describe how to build a robust spring-transport mechanism for a spinning rotor gauge. This device securely immobilizes the rotor and keeps it under vacuum during transportation. We also describe packaging that minimizes the risk of damage during transport. Tests show our design works for typical shocks during transport.

Video: How to Build a Vacuum Spring-transport Package for Spinning Rotor Gauges

Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation

Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy and dynamics1-4. Fundamental studies of photoionization processes of biomolecules provide information about the electronic structure of these systems. Furthermore determinations of ionization energies and other properties of biomolecules in the gas phase are not trivial, and these experiments provide a platform to generate these data. We have developed a thermal vaporization technique coupled with supersonic molecular beams that provides a gentle way to transport these species into the gas phase. Judicious combination of source gas and temperature allows for formation of dimers and higher clusters of the DNA bases. The focus of this particular work is on the effects of non-covalent interactions, i.e., hydrogen bonding, stacking, and electrostatic interactions, on the ionization energies and proton transfer of individual biomolecules, their complexes and upon micro-hydration by water1, 5-9.
We have performed experimental and theoretical characterization of the photoionization dynamics of gas-phase uracil and 1,3-dimethyluracil dimers using molecular beams coupled with synchrotron radiation at the Chemical Dynamics Beamline10 located at the Advanced Light Source and the experimental details are visualized here. This allowed us to observe the proton transfer in 1,3-dimethyluracil dimers, a system with pi stacking geometry and with no hydrogen bonds1. Molecular beams provide a very convenient and efficient way to isolate the sample of interest from environmental perturbations which in return allows accurate comparison with electronic structure calculations11, 12. By tuning the photon energy from the synchrotron, a photoionization efficiency (PIE) curve can be plotted which informs us about the cationic electronic states. These values can then be compared to theoretical models and calculations and in turn, explain in detail the electronic structure and dynamics of the investigated species 1, 3.

Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet VUV Synchrotron Radiation

A molecular beam coupled to tunable vacuum ultraviolet photoionization mass spectrometer at a synchrotron provides a convenient tool to explore the electronic structure of isolated gas phase molecules and clusters. Proton transfer mechanisms in DNA base dimers were elucidated with this technique.

Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy ...

Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays

In this article, we describe a simple method to reversibly tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays. Here, CNT arrays are defined as densely packed multi-walled carbon nanotubes oriented perpendicular to the growth substrate as a result of a growth process by the standard thermal chemical vapor deposition (CVD) technique.1,2 These CNT arrays are then exposed to vacuum annealing treatment to make them more hydrophobic or to dry oxidation treatment to render them more hydrophilic. The hydrophobic CNT arrays can be turned hydrophilic by exposing them to dry oxidation treatment, while the hydrophilic CNT arrays can be turned hydrophobic by exposing them to vacuum annealing treatment. Using a combination of both treatments, CNT arrays can be repeatedly switched between hydrophilic and hydrophobic.2 Therefore, such combination show a very high potential in many industrial and consumer applications, including drug delivery system and high power density supercapacitors.3-5
The key to vary the wettability of CNT arrays is to control the surface concentration of oxygen adsorbates. Basically oxygen adsorbates can be introduced by exposing the CNT arrays to any oxidation treatment. Here we use dry oxidation treatments, such as oxygen plasma and UV/ozone, to functionalize the surface of CNT with oxygenated functional groups. These oxygenated functional groups allow hydrogen bond between the surface of CNT and water molecules to form, rendering the CNT hydrophilic. To turn them hydrophobic, adsorbed oxygen must be removed from the surface of CNT. Here we employ vacuum annealing treatment to induce oxygen desorption process. CNT arrays with extremely low surface concentration of oxygen adsorbates exhibit a superhydrophobic behavior.

This article describes a simple method to fabricate vertically aligned carbon nanotube arrays by CVD and to subsequently tune their wetting properties by exposing them to vacuum annealing or dry oxidation treatment.

In this article, we describe a simple method to reversibly  tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays.  Here, CNT ...

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial resolution, and is even capable of providing atomically resolved elemental maps. In this technique, a highly focused electron beam is incident upon a thin sample and the energy of emitted X-rays is measured in order to determine the atomic species of material within the beam path. This elementally sensitive spectroscopy technique can be extended to three dimensional tomographic imaging by acquiring multiple spectrum images with the sample tilted along an axis perpendicular to the electron beam direction.
Elemental distributions within single nanoparticles are often important for determining their optical, catalytic and magnetic properties. Techniques such as X-ray tomography and slice and view energy dispersive X-ray mapping in the scanning electron microscope provide elementally sensitive three dimensional imaging but are typically limited to spatial resolutions of &gt; 20 nm. Atom probe tomography provides near atomic resolution but preparing nanoparticle samples for atom probe analysis is often challenging. Thus, elementally sensitive techniques applied within the scanning transmission electron microscope are uniquely placed to study elemental distributions within nanoparticles of dimensions 10-100 nm.
Here, energy dispersive X-ray (EDX) spectroscopy within the STEM is applied to investigate the distribution of elements in single AgAu nanoparticles. The surface segregation of both Ag and Au, at different nanoparticle compositions, has been observed.

The use of energy dispersive X-ray tomography in the scanning transmission electron microscope to characterize elemental distributions within single nanoparticles in three dimensions is described.

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial ...

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators &#8212; a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes.

This movie shows how an atmospheric plasma torch can be ignited by microwaves with no additional igniters and provides a stable and continuous plasma operation suitable for plenty of applications.

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

Development of an Experimental Setup for the Measurement of the Coefficient of Restitution under Vacuum Conditions

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their behavior for single stages of a process or even an entire process. For the simulation with occurring particle-particle and particle-wall contacts, the value of the coefficient of restitution is required. It can be determined experimentally. The coefficient of restitution depends on several parameters like the impact velocity. Especially for fine particles the impact velocity depends on the air pressure and under atmospheric pressure high impact velocities cannot be reached. For this, a new experimental setup for free-fall tests under vacuum conditions is developed. The coefficient of restitution is determined with the impact and rebound velocity which are detected by a high-speed camera. To not hinder the view, the vacuum chamber is made of glass. Also a new release mechanism to drop one single particle under vacuum conditions is constructed. Due to that, all properties of the particle can be characterized beforehand.

The coefficient of restitution is a parameter that describes the loss of kinetic energy during collision. Here, a free-fall setup under vacuum conditions is developed to be able to determine the coefficient of restitution parameter for particles in micrometer range with high impact velocities.

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their ...

Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. Conventionally reserved for the fabrication of metal thin films, thermal evaporation deposits bismuth into an array of vertical single crystalline nanowires over a flat thin film of vanadium held at RT, which is freshly deposited by magnetron sputtering or thermal evaporation. By controlling the temperature of the growth substrate the length and width of the nanowires can be tuned over a wide range. Responsible for this novel technique is a previously unknown nanowire growth mechanism that roots in the mild porosity of the vanadium thin film. Infiltrated into the vanadium pores, the bismuth domains (~ 1 nm) carry excessive surface energy that suppresses their melting point and continuously expels them out of the vanadium matrix to form nanowires. This discovery demonstrates the feasibility of scalable vapor phase synthesis of high purity nanomaterials without using any catalysts.

A protocol for seedless and high yield growth of bismuth nanowire arrays through vacuum thermal evaporation technique is presented.

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. ...

A System to Create Stable Nanoparticle Aerosols from Nanopowders

Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring minimal amounts of test materials (min. 200 mg), for studying powder aerosolization behavior and aerosol properties. The aerosolization procedure follows the concept of the fluidized-bed process, but occurs in the modified volume of a V-shaped aerosol generator. The airborne particle number concentration is adjustable by controlling the air flow rate. The system supplied stable aerosol generation rates and particle size distributions over long periods (0.5-2 hr and possibly longer), which are important, for example, to study aerosol behavior, but also for toxicological studies. Strict adherence to the operating procedures during the aerosolization experiments ensures the generation of reproducible test results. The critical steps in the standard protocol are the preparation of the material and setup, and the aerosolization operations themselves. The system can be used for experiments requiring stable aerosol concentrations and may also be an alternative method for testing dustiness. The controlled aerosolization made possible with this setup occurs using energy inputs (may be characterized by aerosolization air velocity) that are within the ranges commonly found in occupational environments where nanomaterial powders are handled. This setup and its operating protocol are thus helpful for human exposure and risk assessment.

We designed and developed an effective nanopowder aerosolization setup and operating protocol. The system generated nanoparticle aerosols with stable number concentrations and size distributions for long durations, requiring only small quantities of test material (min. 200 mg).

Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring ...

Experimental Procedure for Warm Spinning of Cast Aluminum Components

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to improve material properties. With a wide array of processing parameters which can affect both the shape attained and resulting material properties, this type of processing is notoriously difficult to commission. A simplified, light-duty version of the process has been designed and implemented for full-size automotive wheels. The apparatus is intended to assist in understanding the deformation mechanisms and the material response to this type of processing. An experimental protocol has been developed to prepare for, and subsequently perform forming trials and is described for as-cast A356 wheel blanks. The thermal profile attained, along with instrumentation details are provided. Similitude with full-scale forming operations which impart significantly more deformation at faster rates is discussed.

An experimental protocol for instrumented warm rotary forming of cast aluminum alloys employing a bespoke industrially scaled apparatus is presented. Experimental considerations including thermal and mechanical effects are discussed, as well as similitude with full-scale processing of automotive wheels.

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to ...

Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex donor-acceptor emitters is presented. With a step-by-step procedure, readers will be able to repeat and produce OLED devices based on simple organic emitters. A patterning procedure allowing the creation of personalized indium tin oxide (ITO) shape is shown. This is followed by the evaporation of all layers, encapsulation and characterization of each individual device. The end goal is to present a procedure that will give the opportunity to repeat the information presented in cited publication but also using different compounds and structures in order to prepare efficient OLEDs.

A protocol for the production of simple structured organic light-emitting diodes (OLEDs) is presented.

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex ...

Magnet Assisted Composite Manufacturing: A Flexible New Technique for Achieving High Consolidation Pressure in Vacuum Bag/Lay-Up Processes

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed magnet assisted composite manufacturing (MACM) technique. In this technique, permanent magnets are utilized to apply a sufficiently high consolidation pressure during the curing stage. To enhance the intensity of the magnetic field, and thus, to increase the magnetic compaction pressure, the magnets are placed on a magnetic top plate. First, the entire procedure of preparing the composite lay-up on a magnetic bottom steel plate using the conventional wet lay-up vacuum bag process is described. Second, placement of a set of Neodymium-Iron-Boron permanent magnets, arranged in alternating polarity, on the vacuum bag is illustrated. Next, the experimental procedures to measure the magnetic compaction pressure and volume fractions of the composite constituents are presented. Finally, methods used to characterize microstructure and mechanical properties of composite laminates are discussed in detail. The results prove the effectiveness of the MACM method in improving the quality of wet lay-up vacuum bag laminates. This method does not require large capital investment for tooling or equipment and can also be used to consolidate geometrically complex composite parts by placing the magnets on a matching top mold positioned on the vacuum bag.

A new technique for applying consolidation pressure on the vacuum bag lay-up to fabricate composite laminates is described. The goal of this protocol is to develop a simple, cost-effective technique to improve the quality of laminates fabricated by the wet lay-up vacuum bag method.

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed ...