Design and implementation of a low temperature chamber

Date

5-1999

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Emmanuel A Florido

Abstract

A low-temperature chamber at the range of 77 K to 300 K was conceptualized, fabricated, and interfaced to a personal computer. Liquid nitrogen was used to lower the temperature. Temperature control is achieved by either heating up (heater on) or cooling down (valve open) while the actual temperature and the target temperature at the sample holder are compared by the computer. The temperature sensor used was a thermistor and calibrated obtaining a calibration curve fit of y = 21545.70 * 10 ^ -0.00811x. The instrument was analyzed for stability, accuracy and speed of response based on the results of the 32 trials made. A damped harmonic oscillation could be observed on trials where initial voltage was much different from target voltage. Overshoots from the target voltage causing oscillations was due to the residual heat from heater turned on at a long duration or from the pouring of excess liquid nitrogen.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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