Nanosecond Timers

Abstract

Due to the high cost of atomic clocks, as well as their extreme precision that is rarely needed in the school environment, the purchase of such clock for high school labs is often unjustified. Despite that, many educational experiments or researches, such as speed of light/sound calculation, or cognitive neuroscience experiments, require very accurate timing. The need for a product that could be used by non-engineering faculty and students, or a product that would require no assembly, programming, or soldering is present. My project will solve this issue. I've created a timer that requires minimum knowledge in programming or electrical engineering. The timer is being designed in a way so that it could be easily used by a high school student. As an ultimate test of timer’s precision, it is being sent to the International Space Station to detect the time dilation effect according to the Special Theory of Relativity of Einstein. An important part of my project, this would be the first experiment to observe time dilation effect conducted by a high school student.

Introduction

Finding a nanosecond precision timer is a difficult task, especially if a scientist, a student, or a teacher doesn’t hold specific skills in engineering and computer science. No doubt there are clocks and oscillators in the market that can easily count with nanosecond precision and further, but buying one is often a challenge. Quantum SA.45s Chip Scale Atomic Clock by the Microsemi Corporation can count with 5.0E-11 accuracy for a cost of $1,500. One can also purchase used atomic clocks from eBay ranging from $150 for a 1.0E-7 Rubidium frequency standard atomic clock up to $850 for a 5.0E-13 Cesium frequency standard atomic clock. Due to the high cost, justifying the purchase of an atomic clock could be a challenge for the school faculty, considering that the clock’s full potential might not be needed. Texas Instruments also produce high precision timers, but their precision does not exceed 1.0E-6, and the timer has low frequency stability. All the aforementioned products require further assembly and programming, meaning that the user has to possess a certain skillset in the fields of electrical engineering and computer science in order to use the timer.

I’ve undertaken a problem of designing and constructing a small, low cost, easily manufactured 5.0E-8 precision timer for the purpose of lab usage. It is a module that can be easily connected to the Arduino electronics platform, similar to IMU or LIDAR sensors. As the primary timer application is for it to be used at schools’ or universities’ labs or workshops, the timer has a straightforward and widely used interface that can be easily understood and applied by non-engineering students and scientists. My timer is a part of bigger project held in Princeton International School of Math and Science (PRISMS) and is a part of the payload of a 1U CubeSat payload that was sent to the International Space Station (ISS) in April of 2018. The timer was used in an attempt to observe time dilation effect that occurs according to the Theory of Special Relativity of Einstein. This test acted as an ultimate test of the timer’s precision, providing a number of additional requirements and limitations for the timer’s design.

Two instances of the timer were sent to the ISS. In order for the experiment to be successful, the timers need to be constantly powered for the duration of almost 60 days, as well as during the ascent and descent periods. A set of rechargeable batteries were implemented into the CubeSat to supply the timers with constant power.