Mass spectrometer with electron source for reducing space charge effects in sample beam

A mass spectrometer comprising:

• an ion source which generates a quasineutral beam of positive ions and electrons wherein a total positive charge of the positive ions is substantially equal to a total negative charge of the electrons;
• a sampling interface which extracts a portion of the quasineutral beam from the ion source to form a sample beam that travels along a path and is initially a quasineutral sample beam of positive ions and electrons wherein a total positive charge of the positive ions is substantially equal to a total negative charge of the electrons, but changes to a positively charged sample beam with an excess of positive ions as the sample beam travels along the path, thereby causing space charge effects to develop in the positively charged sample beam due to the excess of positive ions in the positively charged sample beam as the sample travels along the path;
• an electron source which adds electrons to the positively charged sample beam to reduce the excess of positive ions in the positively charged sample beam, thereby reducing the space charge effects in the positively charged sample beam and producing a sample beam having reduced space charge effects;
• and
• a mass analyzer which analyzes the sample beam having reduced space charge effects.

A mass spectrometer comprising:

• a source which generates a charged beam having an imbalance between positive charge carriers and negative charge carriers;
• a sampling interface which extracts a portion of the charged beam from the source to form a sample beam that travels along a path and has an imbalance between positive charge carriers and negative charge carriers over at least part of the path, thereby causing space charge effects to occur in the sample beam due to the imbalance between positive charge carriers and negative charge carriers in the sample beam;
• an electron source which adds electrons to the sample beam to improve properties of the sample beam, thereby producing a sample beam having improved properties;
• and
• a mass analyzer which analyzes the sample beam having improved properties.

A mass spectrometry method comprising the steps of:

• generating a beam including positive ions with an ion source;
• extracting a portion of the beam from the ion source with a sampling interface to form a sample beam that travels along a path and has an excess of positive ions over at least part of the path, thereby causing space charge effects to occur in the sample beam due to the excess of positive ions in the sample beam;
• adding electrons from an electron source to the sample beam to reduce the excess of positive ions in the sample beam, thereby reducing the space charge effects in the sample beam and producing a sample beam having reduced space charge effects;
• and
• mass-analyzing the sample beam having reduced space charge effects with a mass analyzer.

A mass spectrometry method comprising the steps of:

• generating a quasineutral beam of positive ions and electrons with an ion source wherein a total positive charge of the positive ions is substantially equal to a total negative charge of the electrons;
• extracting a portion of the quasineutral beam from the ion source with a sampling interface to form a sample beam that travels along a path and is initially a quasineutral sample beam of positive ions and electrons wherein a total positive charge of the positive ions is substantially equal to a total negative charge of the electrons, but changes to a positively charged sample beam with an excess of positive ions as the sample beam travels along the path, thereby causing space charge effects to develop in the positively charged sample beam due to the excess of positive ions in the positively charged sample beam as the sample travels along the path;
• adding electrons from an electron source to the positively charged sample beam to reduce the excess of positive ions in the positively charged sample beam, thereby reducing the space charge effects in the positively charged sample beam and producing a sample beam having reduced space charge effects;
• and
• mass-analyzing the sample beam having reduced space charge effects with a mass analyzer.

A mass spectrometry method comprising the steps of:

• generating a charged beam having an imbalance between positive charge carriers and negative charge carriers with a source;
• extracting a portion of the charged beam from the source with a sampling interface to form a sample beam that travels along a path and has an imbalance between positive charge carriers and negative charge carriers over at least part of the path, thereby causing space charge effects to occur in the sample beam due to the imbalance between positive charge carriers and negative charge carriers in the sample beam;
• adding electrons from an electron source to the sample beam to improve properties of the sample beam, thereby producing a sample beam having improved properties;
• and
• mass-analyzing the sample beam having improved properties with a mass analyzer.