Low Temperature Heat Pulse Thermal Relaxation Calorimeter - PowerPoint PPT Presentation

1 / 1
About This Presentation
Title:

Low Temperature Heat Pulse Thermal Relaxation Calorimeter

Description:

Low Temperature Heat Pulse Thermal Relaxation Calorimeter. Principle ... of the calorimeter. Calibration of copper with various. magnetic fields ... – PowerPoint PPT presentation

Number of Views:36
Avg rating:3.0/5.0
Slides: 2
Provided by: tosh5
Category:

less

Transcript and Presenter's Notes

Title: Low Temperature Heat Pulse Thermal Relaxation Calorimeter


1
Low Temperature Heat Pulse Thermal Relaxation
Calorimeter
?Principle The specific heat of a substance is
defined as the quantity of heat required to raise
the temperature of a unit mass of the substance
by a unit degree of temperature. The heat
capacity is then obtained as
?Technique The calorimetry technique used
here is known as the time constant or relaxation
method. It consists of changing step-wise the
power supplied to the sample. The variations of
heater power and chip temperature are sketched
below.
Power and temperature during a transient
Sample mounting
schematic chip
The heat capacity is calculated by C ?(1/RTH) ?
(?P/?T0),where RTH?T0/?P is the effective
thermal resistance involving sample, chip and
wire. ?time constant which can be obtained from
the result of thermal transient.
?Experimental chart
Transfer liquid helium into Dewar
Check the needle valves in 1 K pot and sorb
Vacuum the OVC of Dewar
Put the probe into Dewar
Cooling the He3 pot down to 0.5 K
Cut the specimen into propersize (?2 mg)
Start the measurement
Mount sample
Put in the active carbon and connect T-cell with
probe
Put in the exchange gas into IVC (helium gas )
Vacuum the IVC of probe
Put the probe into tank
Bake active carbon
?Result
Field dependence of C/T vs T2
Calibration of copper with various
magnetic fields
Schematic diagram of the insert
of the calorimeter
Write a Comment
User Comments (0)
About PowerShow.com