High-field And Low temperature instrument (HAL-9500)

Location
Area piE3

Beam
Positive surface muons with momentum of 28MeV/c

Muon Polarization
~ 100% (spin rotation ~ 90 degrees) / > 95% (spin rotation ~ 10 degree)

Detectors
2 x 8 positron detectors + muon detector + veto/validation detector

Magnet
Oxford Instrument superconducting split pair magnet (up to 9.5 T)

Cryostat
BlueFors Cryogen-free Dilution Refrigerator (DR) / Janis Flow Cryostat (FLC)

The following detailed information is available:

• Panorama view of the spectrometer in the piE3 experimental area
• Operator's handbook of the Oxford magnet
• Design drawing of the Janis cryostat

Magnetic Field

Magnetic field up to 9.5 T can be applied along the beam by using the Oxford Instruments superconducting split pair magnet. Shim coils are used to adjust homogeneity of the magnetic field in the sample space. Inhomogeneity is smaller than 0.1 mT.

Running the magnet at 4.2 K
0.01 T < H < 8 T

Running the magnet at 2.2 K (lambda point)
8 T < H < 9.5 T

Cryostat

BlueFors vacuum-loaded cryogen-free dilution refrigerator (DR) or Janis continuous flow cryostat (FLC) can be used. The sampe is in a vacuum environment.

DR
Temperature range: ~ 10 mK < T < 10 K
Recommended sample size: diameter 8 mm

FLC
Temperature range: ~ 2.4 K < T < 300 K
Recommended sample size: diameter 8 mm

Detector Arrangement

2 x 8 positron detectors are arranged in two rings. Each scintillator is directly connected to the multi-pixel photon counter (Hamamatsu, 3x3 mm², 3600 pixels), which is unaffected by the magnetic field up to 9.5 T. A veto detector rejects muons which did not stop in the sample.

Wiring Scheme and Front-end Electronics

A wiring scheme (png) is available.

TDC

The TDC electronics is characterized by a logic performed exclusively at the software level.

A manual (html / pdf) is available.

The acquisition software DeltaT (html / pdf) is based entirely on the DAQ software package MIDAS.

Data Format and Storage

The users are responsible to store in a safe place their own data. Every week a backup of the data is performed in the PSI Archive system and the specific muSR ftp-server (see here for more information).

You are strongly adviced to retrieve your data ("bin"-format) using our new ftp-server.

Computers

The area is equipped with an experiment console (running Scientific Linux) pc11320.

The µSR data acquisition system hardware consists of this console and a Linux back-end server (psw416) both located in the experimental hall (PiE3 barracks). This back-end is connected to a front-end PC running Scientific Linux and controlling the VME DAQ unit.