Response to Questions Multispectral Photodetection System.pdf

Response to Questions Multispectral Photodetection System

Questions Responses 1 For the>= 16 spectral channel requirement, do they need separate physical detector channels, or would spectral bin system that captures the full spectrum be acceptable?

This is really the key question. If spectral bins are acceptable, we could recommend an HR6or QEPro. Both have the sen 50 or QEPRO-XR500-50 would be good starting points). If they need separate physical detector channels, they're probably will also help narrow down the best fit.

>= 16 spectral channels was chosen to allow a balance of 1) sufficient spectral resolution (specified as <= 20 nm) to resolve different fluorophores, while 2) maintaining sufficient signal per channel to meet the required performance specifications, and 3) being compatible with NIST instrumentation which accepts up to 32 channels.

Each channel of the detector should fulfill the performance specs (detection efficiency, bandwidth readout noise, dynamic range, and sensitivity specification), and output specs (voltage range, connector, and one analog output per channel). The physical detector format (PMT, APD, Si, or hybrid) is requested for compatibility with the NIST instrument, which uses these physical detectors formats for existing channels.

2 What are the size requirements? Does the device need to be integrated into the flow cytometry system, or can its

The photodetector module(s) can sit next to the NIST system. Thus, size was not listed as a specification, but fiber coupling was listed as a specification.

3 What do they plan to use the voltage outputs for?

• Real-time particle detection?

• Triggering?

• Storage through external digitizers?

• Compatibility with existing electronics?

The analog voltage output (>= 500 kHz bandwidth) from each channel will be directly connected to the NIST serial cytometer and the specifications on the voltage outputs are required for compatibility.

The NIST cytometer digitizes the voltages at 2 MHz per channel and performs all analysis and measurement tasks in real-time using existing software.

4 Can the spectral data be delivered digitally, or are analog outputs required?

Analog outputs are required, as specified, for compatibility with the NIST cytometer.

5 What particle transit times are expected in the Serial Flow Cytometer?

The particle transit time is <= 500 us. These dynamics are accommodated by the specified bandwidth of >= 500 kHz for each channel.

6 Do all four optical inputs need to be measured simultaneously, or can they be time-multiplexed?

The four optical inputs simultaneously generate optical pulses with different timings. As specified, the inputs can be multiplexed by summing to one spectral module, or by splitting across multiple spectral modules.

7 Are the four light sources active at the same time or sequentially? What light sources are they using, and do they r

The four light sources are active at the same time.

The light sources are fiber-coupled fluorescence emissions provided by the NIST instrument.

If they need separate physical detector channels, an option could be the multichannel HR6-based pseudo MX LIBS system application-specific probes and can be built with 4 or 8 channels, with additional benches added if they need more throu

The main concern is that it would be a custom solution, and their document says custom or prototype systems won't be, A commercial spectral photodetector system is requested.