Low Background Inserts
Dealing with Small Samples
Although a muon beam can be focused and/or collimated down to a narrow
diameter, it becomes impractical to go below about 1 cm because
- the muons fill a large phase space, so they can't be focused indefinitely;
- the rate is too low if they are collimated ruthlessly; and
- even for a small collimator, the beam will diverge between the collimator
and the sample as there must be some appreciable distance between them
(for cryostat vacuum etc).
The alternative of having most muons miss the sample is also
undesirable because their `background' signal would overwhelm
the sample signal.
For these reasons, very small or very thin samples require a veto
of muons which do not stop in the sample. While vetos may be used with any
counters, there are some specific counter systems provided as cryostat
inserts.
-
- VH-LowB cryostat inserts
- HiTime - (nee Belle) High-Timing Insert
- μLB cryostat insert
- High pressure cell insert
-
-
-
- HiTime - (nee Belle) High-Timing Insert
- DR
- μLB cryostat insert
Maintained by
Donald Arseneau,
asnd@triumf.ca
for the TRIUMF CMMS