MiniBooNE Vacuum Guide

Introduction

MiniBooNE vacuum is monitored from E28. rom this page, you can look at the pirani gauges, beam valves, ion pumps, and permit status for vacuum related devices. The devices are listed geographicly. Here is an image of the page when vacuum is bad.

Image of E28 with bad readings

List of Devices

The devices are:

BV860
Beam valve at location 860. This must be open to tranport beam.
860
Ion pump at location 860. This is also ACNET device I:IP860.
861
Ion pump at location 861. This is also ACNET devide I:IP861.
862
Two devices here: ion pump and pirani gauge at location 862. These are also ACNET devides I:IP862 and I:PG862.
864
Two devices here: ion pump and pirani gauge at location 864. These are also ACNET devides I:IP864 and I:PG864.
IPavg
Average vacuum in preceeding section.
BV864
Beam valve at location 864. This must be open to transport beam.
866
pirani gauge at location 866. This is also ACNET device I:PG866.
867
Ion pump at location 867. This is also ACNET device I:IP867.
869
Ion pump at location 869. This is also ACNET device I:IP869.
BV871A
First beam valve at location 871. This is located upstream of the Texas Multiwire assembly. This must be open to transport beam.
871
pirani gauge for Texas Multiwire assembly. This is locted in the 871 region. This is also ACNET device I:PG871.
871A
Ion pump for the Texas Multiwire. This is also ACNET device I:IP871A.
BV871B
Second beam valve at location 871. This is located downstream of the Texas Multiwire assembly. This must be open to transport beam.
871B
Ion pump at location 871 (downstream of Texas Multiwre). This is also ACNET device I:IP871B.
873
Ion pump at location 873. This is also ACNET device I:IP873.
IPavg
Average vacuum in preceeding section.
Air
???

Glossary

STP
Standard Temperature and Pressure. This is 0 degrees centigrade and 1 atmosphere (or 273.15 K and 760 torr).
Pirani Gauge
Consists of a filament and a heater. The filament is kept at a constant temperature. The voltage required to do this changes with pressure (due to gas bouncing off the filament and carrying away heat).
Ion Pump
Can operate between 1E-5 torr and 1E-10 torr (looses efficiency after 1E-7 torr). An electric field is set up between the walls and a collector. Any gas is ionized, and "sticks" to the collector. Because the ion flow decreases with pressure, the ion pump can act as it's own gauge.
Beam Valve
A gate valve used to isolate one section of beam pipe from another. It is not only good at stoping air leaks -- half an inch of steel is a pretty good target. You want these open when youtranport beam.

Last Modified:  10 November 2003
Comments:  kobilarc@fnal.gov