Bei der Sicherheitskontrolle durchleuchtet die Mitarbeiterin mein Handgepäck.

German often starts a sentence with a time, place, or situation phrase to set the scene.

So Bei der Sicherheitskontrolle means something like at/during the security check and gives the context first.

That affects word order:

• Bei der Sicherheitskontrolle = first position
• durchleuchtet = still has to be in second position
• die Mitarbeiterin = comes after the verb

This is a very normal German pattern. Compare:

• Die Mitarbeiterin durchleuchtet mein Handgepäck.
• Bei der Sicherheitskontrolle durchleuchtet die Mitarbeiterin mein Handgepäck.

Both are correct; the second one simply emphasizes the setting first.

Because bei always takes the dative case.

The noun is:

• die Sicherheitskontrolle = nominative singular

After bei, it becomes dative:

• bei der Sicherheitskontrolle

So the article changes from die to der.

A useful rule:

• bei + dative

Examples:

• bei der Arbeit = at work
• bei dem Arzt / beim Arzt = at the doctor’s
• bei der Sicherheitskontrolle = at/during the security check

Here, bei means something like at, during, or in the context of.

It does not mean physical closeness in the sense of next to here. Instead, it refers to a situation or event.

So:

• bei der Sicherheitskontrolle = at the security check
• also understood as during the security screening process

This is a common use of bei in German.

Because German main clauses follow the verb-second rule.

That means the conjugated verb must be in the second position, no matter what comes first.

In this sentence, the first position is taken by:

• Bei der Sicherheitskontrolle

So the verb must come next:

• durchleuchtet

Then the subject appears:

• die Mitarbeiterin

Structure:

• Bei der Sicherheitskontrolle | durchleuchtet | die Mitarbeiterin | mein Handgepäck

If the subject came first, then the order would be:

• Die Mitarbeiterin durchleuchtet bei der Sicherheitskontrolle mein Handgepäck.

Durchleuchtet is the 3rd person singular present tense form of durchleuchten.

So:

• infinitive: durchleuchten
• ich durchleuchte
• du durchleuchtest
• sie durchleuchtet

In this sentence, the subject is die Mitarbeiterin, which is she, so German uses the sie form:

• die Mitarbeiterin durchleuchtet

In this meaning, no: it is treated as an inseparable verb.

That is why you say:

• Die Mitarbeiterin durchleuchtet mein Handgepäck.

and not:

• Die Mitarbeiterin leuchtet mein Handgepäck durch.

Also, the past participle is normally:

• durchleuchtet

not:

• durchgeleuchtet

This is useful because many English speakers see durch- and expect a separable verb, but not every durch- verb is separable.

Because Handgepäck is a neuter noun:

• das Handgepäck

It is the direct object here, so it is in the accusative case.

For neuter singular, the possessive determiner mein stays mein in both nominative and accusative:

• nominative: mein Handgepäck
• accusative: mein Handgepäck

Compare with masculine:

• mein Koffer = nominative
• meinen Koffer = accusative

So the sentence uses mein Handgepäck because:

• Handgepäck is neuter
• it is accusative
• neuter accusative singular does not add -en here

It is in the accusative case because it is the direct object of the verb durchleuchten.

The employee is doing the action, and the hand luggage is what is being scanned.

So:

• die Mitarbeiterin = subject, nominative
• mein Handgepäck = direct object, accusative

That is why the sentence means that the employee scans my hand luggage.

Mitarbeiterin is the feminine form of Mitarbeiter.

• der Mitarbeiter = male employee / employee
• die Mitarbeiterin = female employee

The ending -in is a very common way to make a noun specifically feminine in German.

Examples:

• der Lehrer → die Lehrerin
• der Verkäufer → die Verkäuferin
• der Mitarbeiter → die Mitarbeiterin

So this sentence tells us the employee is female.

Yes, both are classic German compound nouns.

They are built from smaller words:

• Sicherheitskontrolle

  • Sicherheit = security/safety
  • Kontrolle = check/inspection
  • together: security check

• Handgepäck

  • Hand = hand
  • Gepäck = luggage
  • together: hand luggage / carry-on baggage

German makes compounds very freely, and the last part is the main word:

• Kontrolle tells you Sicherheitskontrolle is a kind of check
• Gepäck tells you Handgepäck is a kind of luggage

Yes, that is also correct.

German word order is somewhat flexible, as long as the verb-second rule is respected in a main clause.

These are both fine:

• Bei der Sicherheitskontrolle durchleuchtet die Mitarbeiterin mein Handgepäck.
• Die Mitarbeiterin durchleuchtet bei der Sicherheitskontrolle mein Handgepäck.

The difference is mainly focus:

• starting with Bei der Sicherheitskontrolle emphasizes the situation first
• starting with Die Mitarbeiterin emphasizes the person doing the action first