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Video Foil Monitor System ICD

David Gassner

February 2003, BNL

Preface

The Video Foil Monitor (VFM) System is still in the design stage with a

FDR scheduled in FY03. As such, specific hardware configurations have
not yet been selected. It must be understood that this ICD represents
the current design concepts.

# Overall Description

Light produced when the injected beam passes through the primary and
secondary stripping foils is collected via a radiation hardened video
camera. The image is transferred to image acquisition electronics for
analysis. A horizontal and vertical transverse profile can be generated,
as well as information regarding the condition of the stripping foil,
which has a finite lifetime.

The video images will also be available in real time in the SNS control
room.

External timing is required to synchronize the data acquisition with the
macro-pulse structure and provide time stamping.

# General Capabilities

The FVM System will provide the following capabilities:

1.  Video image of the primary stripping foil.

2.  Video image of the primary stripping foil phosphor.

3.  Video image of the secondary stripping foil.

4.  Video image of the secondary stripping foil phosphor.

5.  Remote control of the primary & secondary neutral density filter
    attenuation assembly.

6.  Remote control of primary & secondary lamp illumination.

7.  System testing.

8.  System calibration

## 1. Video image of the primary stripping foil.

Synchronized, time stamped, frame grabbed images of the primary
stripping foil will be processed by the LabView using the NI-IMAQ driver
for the NI-PCI-1409 Image Acquisition board. Each frame will have
characteristics measured (horizontal & vertical profiles, gaussian fits,
etc...) and eventually (with experience) compared to a standard to
determine the integrity of the foil. Positions on the primary foil mount
bracket assembly (mechanical dimensions will be provided) will be used
as fiducials to calibrate dimensions of the image.

A typical digital image produced by video digitization would have a
resolution of 512 (horizontal) X 480 (vertical) pixel resolution and
would have individual pixels with a 5:6 aspect ratio. Setting the
NI-1409 digitizer to 8 bits (10 is optional) would yield about 512 X 480
= 250K bytes/Frame.

A 1000 pulse FIFO history of the primary VFM beam characteristics will
be kept at the console level for use in a "strip chart" or "water fall"
like display. This data will be sent up from the IOCs as packets once
per second.

A real time video image will also be available via the second output
from the video camera.

Each of the 10 stripping foils (used one at a time) will have a unique
identifier, and will be confirmed by querying the foil motion control
system.

## 2. Video image of the primary stripping foil phosphor.

Synchronized, time stamped, frame grabbed images of the primary
stripping foil phophor will be processed by the LabView using the
NI-IMAQ driver for the NI-PCI-1409 Image Acquisition board. Each frame
will have characteristics measured (horizontal & vertical profiles,
gaussian fits, etc...). Fiducial marks on the phosphor screen
(mechanical dimensions will be provided) will be used as to calibrate
dimensions of the image.

A real time video image will also be available via the second output
from the video camera.

The image acquisition software will know when the primary stripping foil
is in place by querying the primary foil motion control system. Also,
the correct neutral density filter will be rotated in place depending on
the intensity of the incident beam (this to be learned by experience).

## 3. Video image of the secondary stripping foil

Synchronized, time stamped, frame grabbed images of the secondary
stripping foil will be processed by the LabView using the NI-IMAQ driver
for the NI-PCI-1409 Image Acquisition board. Each frame will have
characteristics measured (horizontal & vertical profiles, gaussian fits,
etc...) and eventually (with experience) compared to a standard to
determine the integrity of the foil. Positions on the secondary foil
mount bracket assembly (mechanical dimensions will be provided) will be
used as fiducials to calibrate dimensions of the image.

A 1000 pulse FIFO history of the secondary VFM beam characteristics will
be kept at the console level for use in a "strip chart" or "water fall"
like display. This data will be sent up from the IOCs as packets once
per second.

A real time video image will also be available via the second output
from the video camera.

## 4. Video image of the secondary stripping foil flag

Synchronized, time stamped, frame grabbed images of the secondary
stripping foil will be processed by the LabView using the NI-IMAQ driver
for the NI-PCI-1409 Image Acquisition board. Each frame will have
characteristics measured (horizontal & vertical profiles, gaussian fits,
etc...). Positions on the secondary foil mount bracket assembly
(mechanical dimensions will be provided) will be used as fiducials to
calibrate dimensions of the image.

A 1000 pulse FIFO history of the primary VFM beam characteristics will
be kept at the console level for use in a "strip chart" or "water fall"
like display. This data will be sent up from the IOCs as packets once
per second.

A real time video image will also be available via the second output
from the video camera.

Each of the 3 stripping foils (used one at a time) will have a unique
identifier, and will be confirmed by querying the secondary foil motion
control system.

## 5. Remote control neutral density filter attenuation

A six-position Geneva drive style rotating neutral density filter
assembly will be installed between the camera and the lens. One position
(home) will be empty yielding no attention. The remaining 5 positions
will each have decreasing transmittance capabilities (50%, 25%, 1%,
0.5%, 0.1%). The NI-PCI-1409 Image Acquisition board has digital I/O
available for this task. A timed bit (500ms) will necessary to increment
the position of the assembly, this bit will drive a relay which controls
the power to the dc rotation motor. Also, software must keep track which
filter is inserted, and calculate how to get to the next desired filter.
A routine to rotate until home (digital input bit reads home switch) is
required in case the filter position is unknown (power dip, etc. .. ).
The Geneva gear also has a position switch to indicate if the drive is
in the appropriate Geneva position, if not the motor should be rotated
until the switch is made.

## 6. Remote control primary & secondary lamp illumination.

Two halogen lamps will be placed at each foil location to illuminate the
foil or flag to enable viewing of the object's condition, position, and
fiducial mark locations. The lamps will be powered by a DC power supply.
On/Off control will be via a relay from a digital output bit from the
NI-PCI-1409 Image Acquisition board.

## 7. System Testing

Without beam, and the lamp will be turned on, images can be compared to
a reference to ensure system integrity. Neural density filters can be
inserted and light attenuation measured.

There will be local TV monitors in the ring service building to view
live video images from both stripping foil locations.

**8. System Calibration**

Periodically the system will check that the dimensions used in image
analysis correspond to fiducial mark distances.

# System Configuration

## Distribution of VFM's

The two systems, each includes a rad-hard video cameras and a neutral
density filter assembly (and lens) will be located in separate cubbyhole
recesses in the outer radius of the tunnel wall near the injection
region. The illumination lamps (2 each) will be mounted near the viewing
port on the beam line vacuum chamber assembly. The rack-mounted pc will
be mounted in the ring service building.

## Image Acquisition & Control

Each PCI base processor card will acquire one RS-170 video image.
Digital I/O we done through the available channels on this PCI card.

## Timing

A machine synchronous timing signal will be connected to the external
trigger input of the NI-1409 card, and all the cards must be
synchronized together. This timing signal will likely have to be delayed
so the frame capture time is appropriate with beam arrival on the
foil/phosphor. The Dage 70R-VH video cameras also have a video synch
input which needs the same trigger.

## Packaging

The IOC will be a rack mounted PC which will house the video image PCI
cards in addition to motion control PCI cards for the primary and
secondary foil drives. The ND filter and lamp control relays will be
mounted on DIN rail in the back of the rack, this DIN rail will also
serve for cable terminations and inter-rack wiring.

**Cabling**

Video signals (analog).RG-59 Black, 75 Ohms.

Dage cable between camera in ring to Camera Control Unit (CCU) in ring
service building. (1.5" diameter, underwater/radiation rated, it has a
variety of shielded pairs, and coax, and a variety of control voltages
and bias voltages along with video level signals).

Neutral Density Filter: Multiconductor, 20 pair, 20 AWG \"1140\" (about
1 inch diameter, control voltages 5 -- 24 VDC).

Lamps: 18 AWG Multiconductor.

## Process Variables

The various signals to be interfaced to the Control System are shown in
Table I.

**TABLE I**

  ---------------- ---------- ---------- ----------- -------------------- --------------
  **Signal**       **\#       **Type**   **Range**   **Characteristic**   **IOC Rate**
                   Chan**                                                 

  Primary Foil     1          ADC        8 bits      NI-1409 digitizer    30 frames/s
  Image                                              2-40 MHz             250K
                                                                          bytes/Frame

  Secondary Foil   1          ADC        8 bits      NI-1409 digitizer    30 frames/s
  Image                                              2-40 MHz             250K
                                                                          bytes/Frame

  Primary ND       1          Dig Output 1/ch        TTL                  1/sec
  Filter Command                                                          

  Primary ND       1          Dig Input  1/ch        TTL                  1/sec
  Filter Readback                                                         

  Secondary ND     1          Dig Output 1/ch        TTL                  1/sec
  Filter Command                                                          

  Secondary ND     1          Dig input  1/ch        TTL                  1/sec
  Filter Readback                                                         

  Primary Foil     1          Dig Output 1/ch        TTL                  1/sec
  Lamp                                                                    

  Secondary Foil   1          Dig Output 1/ch        TTL                  1/sec
  Lamp                                                                    

  Timing Signal    1          V124S      \-          \-                   Video Sync

                                                                          

                                                                          

                                                                          
  ---------------- ---------- ---------- ----------- -------------------- --------------

**Data Acquisition**

LabView will be used to control all aspects of data acquisition and
digital I/O. Each NI-1409 has 16MB of onboard RAM, enough to store about
75 frames.

**Front End Data Processing**

1.  [Data scaling]{.underline}. Each VFM channel will have calibration
    parameters for the foil or phosphor image based on defined fiducials
    on the objects. The results should be stored in a separate array so
    that data in either engineering or physics units can be presented.

2.  [Detailed Image Characteristics]{.underline}. Image data will be
    processed to generated measurements, for example horizontal and
    vertical FWHM (full width half max), fit to gaussian, maximum and
    minimum pixel value range, etc. . . To be defined further by physics
    requirements.

3.  [Pulse Identification:]{.underline} Date/time stamp sufficient to
    specify macro-pulse.

4.  [Long Term History for Each VPM.]{.underline} A 1000 pulse FIFO
    history of the long term, low level losses for each BLM will be kept
    at the console level for use in a "strip chart" or "water fall" like
    display. This data will be sent up from the IOCs once per second.

5.  [Real Time Video for Each VPM]{.underline}. This image will be
    available by request in the SNS Control Room.

6.  [Handshaking with Motion systems]{.underline}. The system will know
    if a foil, or phosphor, or the blank position is in the beam path by
    monitoring the status of the primary and secondary motion system.

> 7\. [System Test]{.underline}. Without beam, and the lamp will be
> turned on, images can be compared to a reference to ensure system
> integrity. Neural density filters can be inserted and light
> attenuation measured.