MHM-2020 Active hydrogen atomic frequency standard
hydrogen frequency s

Microchip MHM-2020 is a continuation and development of the world's most widely installed active microwave discharge hydrogen maser. It achieves better stability and enhances the unique automatic tuning design of the MHM-2010 through the redesign of electronic components and software.

 

The MHM-2020 is capable of achieving a daily drift rate of <3×10-16 and improved environmental stability, making it suitable for applications that require extreme frequency stability and low phase noise.

 

Designed, manufactured, and tested in the United States, the microwave discharge oscillator focuses on long-term service deployment. Since 1999, 95% of microwave discharge oscillators are still operational in Microchip's facilities. Each MHM-2020 undergoes rigorous quality standards during manufacturing and extensive performance validation testing before deployment.

 

• Frequency reference source for fundamental scientific research

• National timekeeping services

• Radio astronomy: Very Long Baseline Interferometry (VLBI), Very Long Baseline Array (VLBA)

• Deep space tracking and navigation

• GNSS/GPS satellite control

 

**Note: Typically achieved after extended period of unperturbed, continuous operation. Temperature variation: ±0.25°C. Relative humidity: ±10%. **Daily Aging <3 × 10-16 (typical) Note: Achievable after >3mo's operation while applying integrated drift compensation software

Web Network Management and Monitoring

 

 

Real-time monitoring of system status, including RAM and CPU utilization, processes, CPU average load, disk partition information, system uptime, and running time.

 

Display system information, including host name, operating system kernel version, memory, CPU information, and system scheduled tasks.

 

Real-time monitoring of network interface transmission rate, network connections, ARP cache table, and network interface bandwidth display.

 

Directly query the IP address and login date of the most recent logged-in server, as well as the information of the currently logged-in account.

 

• Remote telemetry monitoring via touch screen and secure Ethernet

• Dedicated keyboard or USB/serial port (secure) for flexible instrument control

• Drift compensation mode for drift as low as <3×10-16/day (typical, after 3 months)

• Low hydrogen consumption for long-term maintenance-free operation with a lifespan exceeding 20 years

• Internal clock for marking internal data timestamps

• 1pps synchronization option for precise GNSS calibration

• Multiple 1pps and RF output options (5, 10, or 100MHz)

• Low phase noise option

• Backup battery

• CE certified

 

User-Friendly Interface

 

Intuitive touch screen display, secure Ethernet or serial interface for remote telemetry monitoring, providing various security options.

 

 

MHM-2020 employs an automatic frequency control system to maintain a constant resonant cavity frequency relative to the hydrogen emission line. This technology enables long-term stability, thanks to the most stable cesium atomic standard. Now, by combining this technology with the new integrated drift compensation software, MHM-2020 consistently achieves a daily aging rate of <3×10-16.

 

 

The maser design is engineered to withstand varying voltage, temperature, and magnetic field environments. Through careful selection of electronic components and control of manufacturing processes, each MHM-2020 is designed with a temperature sensitivity of <8×10-15/ºC and a magnetic field sensitivity of <2×10-14/Gauss.

 

 

MHM-2020 can be configured with low phase noise output at the time of factory setup, enabling higher resolution measurements in VLBI applications, deep space communication, and observations. You no longer have to compromise between long-term and short-term stability.

 

 

The lifetime ownership cost of an active maser is an important consideration. MHM-2020 is designed for long lifespan and low maintenance. The hydrogen gas supply is sufficient for over 20 years of operation. An efficient hydrogen state selector minimizes the load on the ion pump (less than 0.01 moles per year), and the pump itself has a lifespan exceeding 20 years at the nominal hydrogen flow rate. The TeflonTM bulb coating requires minimal re-coating and has a lifespan of over 20 years. Additionally, the MHM-2020 is designed for on-site module replacement as needed. We ensure that the MHM-2010 Maser can be upgraded to the new MHM-2020 on-site based on the device's years of usage.

 

 

The maser has four redundant power systems for charging the internal backup battery. In a normal laboratory environment, the battery will maintain full maser performance for up to 8 hours. The system also has two independent AC power supplies. If one maser fails or loses primary power, both power supplies can individually power it. Each power supply can automatically accept 110 or 220 VAC, 50 or 60 Hz input. Additionally, a 24 VDC power system can be connected as a backup power source to the AC power supplies. In the event of all power sources being unavailable, the maser will switch to battery power until exhausted.

 

 

The operation principle of the hydrogen maser is based on the precise emission of microwaves by hydrogen atoms in the appropriate environment at a frequency of 1420405751 Hz. The wavelength of the hydrogen atom is well-known at 21 cm. By phase-locking the extremely low-power and high-purity signal to a high-performance quartz oscillator, the hydrogen maser provides users with incredible long-term stability and excellent phase noise. The active maser exhibits exceptional stability, typically four times that of passive masers and 100 times that of cesium beams (measured over 7 days). The advantages of a hydrogen clock include low clock noise (eliminating the need for reference clock noise corrections) and shorter intervals to achieve the specified frequency stability compared to high-performance cesium (less by a factor of 10,000). The MHM-2020 incorporates patented quadrupole magnetic technology, which enables key features of high performance and long lifespan, achieving exceptional atomic beam focusing, cavity auto-tuning, and proprietary drift compensation software algorithms. Large-scale deployment sites have demonstrated that long-term maintenance-free operation can be achieved by using minimal amounts of hydrogen to minimize ion pump load. Proprietary Teflon™ coating technology is applied to critical components, and dedicated maser equipment is used to control the manufacturing and test verification spectra of each maser.

 

Specifications @ 25˚C (ambient temperature), unless otherwise stated.