# Alternative Beam Tubes 

-   Material Search

    -   Non-Conductive

    -   Magnetically Transparent

    -   Good Vacuum Properties

    -   Radiation Hardness (1 Mrad)

    -   Good Manufacturability

-   Polyetheretherketone

    -   Victrex PEEK™ 450CA30

-   Borosilicate Glass

    -   Pyrex^®^ (Corning)

# Pyrex^®^ Properties

-   Vacuum properties well known...bell jars etc.

-   Radiation resistance -- DOE chose Borosilicate for High Level
    Nuclear Waste Vitrification (Hanford)

-   ASTM C 158 Modulus of Rupture test ongoing

-   Ability to form long tubes by fusing sections together

# PEEK™ Properties 

-   Radiation Resistance:

> Gamma Radiation Resistance of Victrex^®^ PEEK™ 450G
>
> Dose Rate 2 MeV, 1/5mQ, tested on film samples

  ------------------ -------------- -------------------- ------------------
  Dose Rate          Modulus        Yield Stress         Elongation

  (Mrad)             (kg/cm^2^)     (kg/cm^2^)           (%)

  0                  6000           688 ±32              500 ±19

  1000               6000           635 ±8               432 ±22

  2000               6000           614 ±16              261 ±12
  ------------------ -------------- -------------------- ------------------

-   Carbon fiber-filled resin (30%)

    -   Improved stiffness

    -   Eliminates Aerodag coating

# PEEK™ Vacuum Properties 

-   Measured specific out gassing rate (Torr-L/s-cm^2^) \~ 3e^-9^
    NON-BAKED

-   Assuming a 10 foot long tube with 100 L/s ion pumps on each end, the
    pressure at the pumps would be:

    -   1.1e^-7^ Torr for a 3\" ID

    -   1.4e^-7^ Torr for a 4\" ID

> (Data generated by Terry Anderson 9/12/01)

-   All tests performed on cast material. Additional testing required on
    extruded tube.

**Pyrex**^®^ **Vacuum Forming Process**

-   Rotating Vertical Mandrel

    -   303-304 SS, Graphite

    -   High surface finish imparted to tube

    -   No taper required

-   Mechanized Torch

-   Pull vacuum in outer tube

-   Fuse Pyrex^®^ rods into rough shape

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-   Join 2 tubes using alignment mandrel

**Pyrex**^®^ **Vacuum Forming Process**

-   Grinding to Final Size

    -   Horizontal surface grinder

    -   Form grind outside corners

    -   Straightness ±.010" full length all 4 sides

-   Full Polish Tube Exterior

    -   Silicon carbide

    -   Inspect for bubbles and cracks

    -   Polariscope for stress

    -   Any flaw and tube is rejected

**Optimized Tube Dimensions**

-   Improved Aperture

    -   Kickers & Lambertsons

    -   40 π mm.mrad/95% full width (1.10"horiz. X .59"vert.)

    -   PEEK™ vs. Pyrex^®^

-   Stress Analysis (ANSYS)

    -   Modeled uniform external surface pressure (atmospheric)

    -   Peak stresses

    -   Maximum deflection

**Secondary Operations - Pyrex**^®^

-   Graded Seal

    -   Oxidize kovar flange

    -   Housekeeper seal to oxide layer

    -   Intermediate sealing glass to Pyrex^®^

    -   Tesla coil test for seal integrity

-   Polymer Coating

    -   Scratch protection during handling and installation

    -   Implosion containment

**Secondary Operations - PEEK™**

-   Mechanical Seal

    -   Mill circumferential groove

    -   Clamp to groove

    -   U-shaped spring seal on tube end

    -   Belleville washers

-   Coating to reduce permeability

![](media/image1.jpeg){width="8.739583333333334in"
height="6.499305555555556in"}

![](media/image2.jpeg){width="8.5in" height="11.0in"}

![](media/image3.jpeg){width="8.379861111111111in" height="6.5in"}

![](media/image4.jpeg){width="8.5in" height="11.0in"}

![](media/image5.jpeg){width="8.425in" height="6.492361111111111in"}

![](media/image6.jpeg){width="8.5in" height="11.0in"}

![](media/image7.jpeg){width="11.0in" height="8.5in"}

![](media/image8.jpeg){width="8.379861111111111in" height="6.5in"}

![](media/image9.jpeg){width="8.5in" height="11.0in"}

**Summary**

+---------------------------+-------------+--------------+------------+
|                           | **Ceramic** | **Pyrex^®^** | **PEEK™**  |
+---------------------------+-------------+--------------+------------+
| Mechanical - Dimensional  | Fair        | Very Good    | Good       |
+---------------------------+-------------+--------------+------------+
| Mechanical -- Strength    | Good        | Uncertain    | Good       |
|                           |             |              |            |
| (under vacuum)            |             |              |            |
+---------------------------+-------------+--------------+------------+
| Mechanical - Durability   | Requires    | Requires     | Good       |
|                           | Caution     | Caution      |            |
+---------------------------+-------------+--------------+------------+
| Vacuum Properties         | Very Good   | Good         | Fair       |
+---------------------------+-------------+--------------+------------+
| Radiation Resistance      | Very Good   | Uncertain    | Good       |
+---------------------------+-------------+--------------+------------+
| Chemical Resistance       | Good        | Good         | Good       |
+---------------------------+-------------+--------------+------------+
| Experience in this        | Yes         | No           | No         |
| application               |             |              |            |
+---------------------------+-------------+--------------+------------+