BLOX turns arc patterns into actionable insights

September 16, 2025

Arcing is a common but critical event in high-voltage X-ray systems. While occasional arcs are normal, repeated or clustered arcs over time can signal instability in the module and lead to long-term damage. BLOX helps OEMs and users detect these patterns early – and take preventive measures before failure occurs.

High-voltage X-ray systems are designed for precision and resilience—but even the most robust modules have their limits. One common issue we encounter in the field is recurring arcing. While a few arcs here and there can be normal, extended periods with frequent arc events are an early warning sign of system instability.
Arcing is not always immediately disruptive, but it often points to a deeper issue: instability in the tube, HV cable, or generator. Without timely intervention, this instability accelerates wear and increases the likelihood of unplanned downtime. With BLOX, OEMs, service teams, and end users gain the visibility needed to detect these patterns early and take action—before serious damage occurs.

Issue & cause

  • Arcing is a very common issue that we record on almost every module. The severity can range from “low” to “very severe,” making it essential to act preventively.

What we often encounter

  • End users encountering unstable periods with arc sequences often don’t perform the extra care needed to stabilize the module. Instead, they rely on automated retry routines. 

OEMs, when not notified by end customers, remain unaware of the instability and cannot act preventively or recommend corrective measures - often there is a complete absence of stabilization measures, such as extended warm-ups, over long periods. 

After the period with 62 arcs per day, the module was irreparably damaged


In one example, a customer experienced up to 62 arcs per day, a volume that, if left unaddressed, can rapidly degrade system performance - and in this case the module was irreparably damaged. As a rule of thumb, more than a couple of arcs per day, especially if they occur frequently with no time gaps in between, should be taken very seriously. If left unchecked, arcing usually gets worse over time. To bring clarity to arc behavior, Comet introduced a dedicated metric: Arc Robustness - the number of arcs per 24 hours HV ON. The higher the number, the lower the robustness, and the higher the system instability. This variable provides a reliable signal for identifying performance drifts over time.

If we look closer, an extended period of low arc robustness was registered long before the final crash, with 62 arcs per day.

 

Extended period of very low Arc Robustness with up to 7 arcs per 24 hrs HV ON

How to spot it

BLOX makes arcing trends easy to see and interpret. In the Daily Events Chart, you can track:

  • Number of arcs per day
  • Arc Robustness - number of arcs per 24 hrs HV ON trend line
  • Corrective actions like warm-ups - short, medium and long, mapped over time

In the case mentioned above, the customer experienced a prolonged period of low arc robustness, with almost no warm-ups applied. Only one short warm-up was performed, and it was done weeks too late, far outside the window where it could have helped. The first medium-sized warm up came even later, well after the period of critical instability. This failure to act allowed the module to deteriorate toward an avoidable failure. 

Example of the trace of an arc

Consequences

While a single arc may seem harmless, frequent and clustered arcs have a cumulative effect. Each arc adds thermal and electrical stress to system components.

The result is often:

  • Long-term instability in system operation
  • Accelerated wear of the tube or generator
  • Increased risk of unplanned downtime
  • Premature failure of expensive components

In this case, the absence of preventive measures—like timely warm-ups meant that a minor issue quietly escalated into critical system failure. These events are preventable when spotted early and addressed promptly.

Example of the trace of an arc

Recommendations

When BLOX shows a recurring pattern of low Arc Robustness, act early and follow a structured response:

  • Step 1: Contact the end user immediately and recommend performing 1–2 extended WarmUps. In many cases, a single phone call and a simple procedure can restore system stability remotely
  • Step 2: If arcs continue, schedule a preventive service visit. You know the data and are aware of the problem. You have the right tools with you to run a dummy plug test to isolate whether the issue is with the generator, the HV cable, or the tube.
  • Step 3: If regular maintenance is scheduled soon, evaluate whether the system can safely continue running. You know the data and are aware of the problem, and are prepared to run diagnostics at the beginning of the visit and act on results immediately.
  • Step 4: Once the root cause is identified, order the correct spare part and resolve the issue before it escalates

Proactive attention not only prevents downtime—it reduces service costs, improves tube lifetime, and builds trust between OEMs, integrators, and end users.

First medium size warm-up corrective measure applied way too late after the long period of very low Arc Robustness

From data to action with BLOX

BLOX transforms raw event data into actionable insights. By visualizing arcing behavior through Arc Robustness, daily event trends, and user activity logs, BLOX gives service teams the clarity they need to act early, confidently and efficiently. When decisions are guided by data, service becomes smarter, collaboration improves, and uptime shifts from a goal to a given.

Is your system showing signs of instability?

Make module data analysis part of your monthly routine - you will know the health status of your module within seconds. Use BLOX to see what's really happening, and respond before small issues become big problems. 

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